Waterlogged – A Dogma-Shattering Book?

Stay the CourseDogma-shattering: an idea integral to the creation and evolution of ultrarunning – a sport created out of the notion that we could run longer and farther, beyond road and track, than anyone believed was possible.

Modern trail ultrarunning was borne from the notion of refusing to accept the belief that no one could run a hundred miles through the mountains in a single day. Done.

Then, no one could run all the uphills in that fabled Sierra Nevada foot race. Done again.

No one, let alone a woman, could cover 47 miles a day for weeks and months on the Appalachian Trail. And no one, period, could eclipse the fifteen-hour barrier at Western States. Done, and done.

Ultramarathon running has pushed the limits of conventional wisdom on all things in human performance: distance and speed, nutrition, and even footwear. Indeed, it was the tales of the rubber tire-shod indigenous ultrarunners of the Copper Canyons that fueled the mainstream adoption of minimalist running, smashing the dogmatic belief in the necessity of hyper-engineered shoes.

It is fitting, then, that the sport of ultramarathoning be ground zero for more dogma-shattering in another area: hydration in endurance exercise.

A new book by renowned sport medicine expert, Tim Noakes, MD, aims to change our beliefs – many of them longstanding, many of them inaccurate – on what it means to fuel optimally in endurance sports:

  • Drink only to thirst, not on a schedule.
  • Drinking does not prevent heat illness.
  • Ingesting salt is unnecessary in ultras.
  • Urine frequency or color has nothing to do with hydration or kidney function.

Say what? Them’s fightin’ words!

Noakes knows it, but he’s ready for the fight. And, with his background, there’s no one better armed. Dr. Noakes has been studying running and endurances sports for nearly fifty years. He has authored or co-authored over 250 scientific studies, including over fifty that examine the role of hydration and electrolytes in sports performance. In addition to sitting on the boards of the American College of Sports Medicine and the International Olympic Committee’s Science Academy, he’s also an experienced ultrarunner: having raced over seventy marathons and ultras, including the famed Comrades Marathon in his native South Africa. One could argue that he wrote the book on distance running: his Lore of RunningLore of Running is one of the most thorough, expansive scientific work on running, and, in its fourth edition, it is standing the test of time.

It was his work with Comrades that first sparked his interest in fluid replacement science. In 1981, Noakes received a letter from a Comrades participant describing her acute illness and hospitalization after that race, the result of drinking too much.

This perplexed and troubled Noakes: he subscribed to the early studies showing relationships between body temperature and weight loss, and was an early proponent of the “drink as much as you can” movement, pervasive to the sport in the 1980s and ‘90s. However, this letter – and mounting cases of Exercise-Associated Hyponatremia (EAH) – caused him to re-evaluate, not only his own beliefs, but also the existing research.

Combining empirical research, fundamentals of human physiology, and numerous performance studies, Waterlogged is an exhaustive look at the research, past and present, the origins of the “dehydration myth” and the role of industry in its propagation, and what athletes really need for optimal performance and safety.

An Argument for Self-Regulation                                          

At its core, Waterlogged is a work that sets out to defend the fundamental biological quality of self-regulation – the idea that the body possesses mechanisms to self-regulate its own physiology to survive any physical challenge, no matter how extreme.

For various reasons – flawed or misinterpreted research, personal beliefs, or outright fear – many people – scientists, physicians, and athletes, alike – began to adopt the “catastrophe model.” Dr. Noakes describes it herein:

“According to this catastrophe model, the body cannot accommodate even small increases in body temperature during exercise, nor can it adjust to the fluid and sodium deficits that develop as it loses both in sweat during exercise. Instead, when exposed to exercise under demanding conditions, the body will simply continue without control until eventually a catastrophic physiological failure must inevitably develop.”

Based on this belief system, the sports medicine community – ranging from doctors to coaches and athletes – has recommended that all exercisers must avoid deficits of fluid – as well as salt and glucose –at all costs. Moreover, this belief system insists that our built-in controls are “hopelessly inadequate,” and that only by overriding these controls can we as athletes avoid catastrophic failure – ranging from DNF to death.

Indeed, this belief system – pushed powerfully by a burgeoning sports drink industry – fueled radical changes in how we fuel for endurance exercise. Within a few years, our drinking habits changed from “not a drop” to “drink as much as you can.” And not without consequence.

The Emergence of Hyponatremia in Endurance Sports

Exercise-Associated Hyponatremia (EAH, or simply hyponatremia) is a condition of decreased blood sodium concentration. Once exceedingly rare if not unheard of during endurance exercise, EAH has exploded in incidence across all events, ranging from marathons to triathlons, to even shorter sub-marathon events.

Its symptoms – weight gain, swelling, nausea and vomiting, headache, muscle cell breakdown, altered consciousness and seizure – were, for years, erroneously attributed to either heat exhaustion or dehydration. As such, EAH was incorrectly treated with the exactly the thing that caused it – more water!

The results can be dangerous and deadly. Excess water causes muscle cells to balloon and burst. It drowns nerve cells. But left unabated, the water accumulates in the confined space of the skull, causing brain tissue to herniate – the brain stem pushes its way out the base of skull, causing death.

Recreational athletes – running easy, in cool temperatures, minding recommendations to “drink as much as you can, to drink before you’re thirsty!” – began showing up in the hospital instead of the finish line.

Some of them were dying.

Hyponatremia was nearly non-existent before the 1970s. Where did it come from?

The Florida Panhandle: Where Dogma – and The Sports Drink Industry – Was Born

Waterlogged tells the story of the creation of Gatorade, the world’s first electrolyte drink. In August of 1965, an assistant football coach for the University of Florida, Dewayne Douglass, shared lunch with a renal scientist, Dr. Dana Shires, at the university, where the coach described his team’s struggles with “heat exhaustion and dehydration.” In that meeting, he implored the scientist and her team – which included renowned renal scientist Robert Cade – to develop “something to negate the strain of the brutal summer heat.” She returned to the lab, conferred with Dr. Cade and within two months, an experimental electrolyte solution was field tested: first with a freshman and varsity B-team scrimmage, and then in a real contest between the Gators and Louisiana State. Based on those two outcomes – second-half “rallies” by both the downtrodden freshman and the underdog Gators – the Legend of Gatorade – was born. The drink was adopted by college and pro teams, alike, and a new industry developed.

It doesn’t take a PhD or a background in research to determine the flaws in this experiment: the lack of any controls and the inability to control placebo effect: the players were given a drink that, coaches insisted, would help.

(It’s worth noting by Dr. Noakes that the success of the ’65 and ’66 Gators also included stellar play from legendary quarterback and future coach, Steve Spurrier, who won the Heisman Trophy in ’66. More notable is that Spurrier drank Coca-Cola, not Gatorade, during games!)

Later studies of Gatorade – performed years after the drink was successfully marketed and sold to masses – demonstrated only that ingesting glucose during competition was beneficial. Every subsequent study of Gatorade failed to demonstrate any significant benefit from the ingestion of either water or low-concentration sodium on core body temperature, blood sodium concentration, and performance.

In some cases, of the opposite was found.

The Tipping Point of Overhydration & Endurance Running: the Wyndham and Strydom Studies

One of the early studies examining hydration, core temperature and weight loss was conducted two South African researchers, Cyril Wyndham and Nic Strydom. Pre-eminent researchers in thermoregulation, they decided to study the role of hydration and marathon running. Their 1969 study found a loose correlation between rising core temperature and percent weight loss during marathon running. Based on those findings, they concluded that dehydration caused core temperature increases, and that, allowed to continue unabated (read: catastrophe model), runners are at high risk for heatstroke unless they drink.

Based on their study, they inferred that the optimal fluid for marathoners to be nearly a liter per hour – roughly two to three times that of previous studies, and an order of magnitude greater than what the elite marathoners of ‘60s were ingesting – in order to prevent the “dangers” of heatstroke.

Initially, the study was tough to argue: it showed a neat, linear relationship between water deficit and core temperature, indicating that any level of dehydration equated to core temperature rise.

But their study was flawed:

  • The runners they examined were not allowed to drink any water – rather than compare multiple levels of hydration, they studied only a group that disallowed any fluid.
  • The runners were advised to run as hard as they could; their efforts were not controlled.
  • There was no correlation of race performance with dehydration and core temperature. This is notable, because the winners of these race studies also happened to have the highest core temperature and weight loss.

Perhaps pressured to release this data and save the masses from impending danger, Wyndham and Strydom failed to execute a thorough study. That, coupled with the emergence of an industry giant replete with anecdotes of athletic prowess, was enough to spin the cogs of hydration dogma for decades: “Drink before you get thirsty! Replace all fluid and electrolytes lost during exercise!”

Evidence-Based Findings

Noakes began to review the literature pre-Wyndham and Strydom, as well as studies that occurred in its aftermath. Moreover, he conducted his own work. Waterlogged lays out this work dissecting the bad from the good, and presents it to the reader in plain view. Studying events ranging from the standard marathon to hundred-mile and 24-hour endurance competitions, Noakes determined the following:

The Role of Hydration and Performance

  • Dogma: In order to ensure optimal performance and/or survive endurance events, one must replace all lost fluids by drinking during the event.
  • Science: Fluid (and weight) loss during endurance exercise is normal, if not optimal.

Noakes notes that studies of top performers in endurance events (marathon, triathlon and long-ultras) typically demonstrate weight losses ranging from 2% to upwards of 8% or higher. More notable, weight loss was correlated to performance in these studies. Conversely, weight gain is correlated to impaired performance and – in most cases – a clinical sign of EAH.

The explanation of these findings is two-fold: first, that sugar (in the form of blood glucose and liver and muscle glycogen) is stored with surrounding water, and that when we burn that sugar, the water leaves with it. Therefore, a significant degree of weight loss due to burned glucose and freed water is normal. This value is now accepted to be in the 2% range.

Second, a significant volume of fluid lost during exercise – through vapor, sweat, or urine – comes from extracellular fluid (ECF). This fluid lies in between cells, as opposed to water found within cells (intracellular) or within blood volume (previous studies have shown that upwards of 70-80% of fluid losses are from ECF and glucose storage, not cellular or plasma water).

Therefore, we stand to lose significant volumes of water weight via sugar storage and ECF without physiological – or performance – consequence.

He argues that only when weight loss is coupled with uncorrected thirst, does performance impair due to dehydration.

Hydration and Thermoregulation

  • Dogma: We must drink water in order to prevent heat illness during exercise in hot conditions.
  • Science: There is no relationship between fluid intake and hydration, and the incidence of heat exhaustion or heatstroke. The only correlate to core temperature is running pace.

Noakes cites volumes of research studies athletes across all sports and events: American football players, marathoners, ultrarunners, and recreational walkers. There is not a single study that demonstrated a difference in core temperature between athletes who drink and those who do not. Nor has there been any evidence – empirical or case study – that links heat exhaustion or stroke to high levels of fluid loss, sodium loss, or the cessation of sweating.

Instead, the only behavioral factor that influences core body temperature during exercise is effort. Again citing the physiological theory of self-regulation and empirical study, Noakes points out that the body will automatically adjust pace in order to ensure that core temperature does not exceed normal thermoregulation (deemed to be <40-42⁰C).

Only pace – dictated by the degree to which our muscles work, burning energy and generating heat – determines core temperature. As such, the athletes who ran the fastest – and won – had the highest core body temperatures, with correlational fluid losses.

It is notable, however, that additional evaporative and external cooling measures – such as ice packs and water dousing – do result in changes in tissue temperature. Indeed, the only acceptable medical treatment for acute heat illness is external cooling via ice packs – not the administration of intravenous fluids, as some may believe.

Heat illness, namely heatstroke, is extraordinarily rare in endurance sports, Noakes points out. Using the clinical definition – a core temperature above 42⁰C, he identifies only six documented cases of heat stroke during endurance (marathon or above) since 1905.

Heat exhaustion or heat stroke is far more common in shorter running events, in large part because the intense efforts and short durations of these events merge to create temperature increases before the body can self-regulate pace. In the vast majority of cases, the heat illness quickly resolves with rest and, when necessary, cooling measures.

Dr. Noakes points out that in most cases of fatal heat illness, there exists an abnormal mechanism of heat build-up – excessive endogenous heat production – whereby the body goes haywire, producing heat, regardless of external temperature or duration of effort. Says Noakes, “this is the only explanation for the large number of cases of heatstroke that occur in cool conditions, or in athletes exercising at a low intensity, or those who have been physically active for only a short time, or in those who have been actively cooled for many hours.” Moreover, some cases have shown insidious spikes in core temp, hours – if not days – after cessation of exercise and onset of treatment.

The high incidence of heat stroke in short distance events – versus virtually none marathons and ultras – also shines light on the lack of connection between hydration and core body temperature. That heat illness is so prevalent in short-lasting events – where very little fluid is lost, yet there is next to no incidence in multi-hour efforts, even with profound water loss – is telling.

Sodium Balance and Performance

  • Dogma: We need to supplement with sodium to complete long-distance endurance events.
  • Science: The body self-regulates blood sodium concentration via several mechanisms, including sodium sparing in sweat and urine. When one “drinks to thirst,” blood sodium concentration invariably rises during prolonged exercise; it never falls.

One of the most persistent beliefs in ultrarunning is that we must ingest sodium for optimal performance, if not survival. Not so, claims Noakes. He points out several studies, including sodium deprivation studies involving prolonged exercise over several days, that demonstrates that the body will maintain blood sodium levels in a deprivation state.

In explaining this phenomenon, Noakes points out our biological mechanisms to preserve sodium in both sweat and urine – pointing out that these studies measured sodium concentrations next to nothing during prolonged exercise and sodium deprivation. Moreover, blood sodium concentrations stayed within normal ranges – so long as athletes and subjects drank only to thirst.

  • Dogma: Heavy sodium concentrations in sweat – evidenced by salt-staining on skin and clothing – identifies a person as a “salty sweater”, and that these people need even more sodium supplementation.
  • Science: The self-regulation of sodium concentration results in sodium excesses being secreted; salty secretions will cease when sodium balance is achieved.

Simply put, the presence of salt deposits on skin and clothing are due to the body ridding of excesses, and when sodium balance is achieved – or if a blood sodium deficit is perceived – the body will conserve it from sweat and urine.

  • Dogma: Sodium supplementation stops and prevents Exercise-Associated Muscle Cramping (EAMC)
  • Science: There is no scientific evidence that shows sodium (or other electrolyte) deficits in those with muscle cramping.

This is another interesting dogma that has thrived, pre-dating even Gatorade. The original belief of salt deficits and cramps was based, according to Noakes’ review of research, on studies of a single miner in the 1920s, who showed salt and fluid losses in association with cramps.

Noakes points out many studies that not only fail to show an association, but demonstrate normal – if not mildly elevated – blood sodium concentrations in those with muscle cramps. Conversely, it is well accepted that those suffering from hyponatremia do not suffer from muscle cramps – the very patient population that would, in theory suffer the most cramping, should a sodium deficit truly cause cramping. Internal or external temperatures also do not play a role, as EAMC occur in cool conditions (including extreme cold water swimmers).

Interestingly, more recent studies have even shown that ingesting electrolyte drinks actually increase cramping incidence: a 2005 study found a 68% incidence of those drinking Gatorade, versus a 54% drinking water, or nothing. And there may be a reason for that.

The current leading theory on muscle cramping is that neuromuscular fatigue – and the loss of inhibitory reflexes – causes excessive muscle activity, resulting in cramping. Moreover, a 2011 study has identified those two risk factors for developing cramping: previous cramping experiences, and faster finishing times; not body weight losses or blood sodium levels. This could explain the greater incidence of cramps amongst Gatorade drinkers: if an athlete perceives protection from drinking it – along with the ergogenic aid of glucose solution – they will run more intensely, possibly resulting in more cramps.

Anti-Diuretic Hormone – the Lynch Pin in Hyponatremic Illness and Death

  • Dogma: The frequency and color of my urine will tell me whether or not I am adequately hydrated; I should continue to drink after exercise until I am able to urinate – to ensure optimal hydration and kidney function.
  • Science: The presence of excessive anti-diuretic hormone during exercises – referred to as Syndrome of Inappropriate ADH (SIADH) secretion – can cause overt fluid retention and resulting in concentrated or complete lack of urine, despite severe overhydration and hyponatremia.

Antidiuretic Hormone (ADH) is secreted during exercise to conserve water from urine, when the brain determines that blood sodium levels are increasing. When sodium levels are balanced, ADH secretion stops. This is the principal reason that, for most of us, we urinate less (or not at all) during prolonged exercise, or that we urinate a lot when well-hydrated.

For reason unclear to scientists, in a significant population of runners (measures as high as 13% of Boston Marathon runners in a 2002 study) exhibit excessive levels of ADH. This condition, referred to as Syndrome of Inappropriate ADH secretion (SIADH), causes athletes to retain water beyond physiologically need, despite potentially severe overhydration and hyponatremia.

These are the runners that may exhibit symptoms of EAH – swelling, weight gain, impaired performance and brain function – yet report either dark urine or none at all. Yet this has nothing to do with the integrity of the kidneys; it is the presence of high levels of ADH that result in the body holding onto this water.

The presence of SIADH – measured in blood lab tests – has been a common finding in the most severe cases of hyponatremia, including deaths. In short, ADH prevented any passage of urine.

To reiterate: there is zero correlation between frequency or color of urination and hydration, or kidney function. ADH controls whether or not the kidney produces urine. Therefore, runners attempting to ensure hydration or kidney function with copious fluids might be endangering their race, if not their health, if there is excessive ADH in their bloodstream, blocking urine production. Indeed, given that hyponatremia leads to muscles cell lysis (explosion due to swelling), one might be endangering his kidneys with excessive drinking during or after endurance events.

The only things we can trust to ensure adequate fluid intake, according to Noakes, is our thirst and, to a lesser extent, the scale. The absence of thirst and an increasing weight (either absolute, or relative) is evidence that additional fluid is unnecessary and potentially dangerous.

Treatment and Prevention of Exercise-Associated Hyponatremia

As dangerous and deadly as EAH can be, the treatment – if initiated promptly and correctly – is quite simple. Research and clinical application has shown that a simple 100-mL “mini-IV” of high-concentration saline solution (3.0% of greater) produces rapid recovery of even the severely hyponatremic – within minutes.

Notable are studies that found a simple ingestion of the same volume and concentration of sodium solution does not have the same restorative effect. It is not known at this time why simply ingesting sodium is less effective.

Either treatment is far cry from what many hyponatremic runners receive – both at medical aid stations and local hospitals, which is typically more fluid, or intravenous solutions with inadequate sodium concentrations – typically 0.9% or less. Noakes implores sports medicine officials – and public health officials, alike – to make a thorough and accurate diagnosis of a hospitalized runner before initiating any IV fluids.

Given this reality, it is even more shocking that a major ultramarathon, at one point, was offering default intravenous solutions, post-race, without any medical justification. It could’ve killed someone.

Evidence-Based Fueling Recommendations for Optimal Performance and Safety

Drink only to thirst.

According to Noakes and the body of research on hydration and performance, individual differences are too great to make blanket recommendations. The only gauge for fluid need is thirst; the only symptom of dehydration is thirst.

Having said that, Noakes goes on to recommend fluid intake in the range of 400-800ml per hour for athletes across all endurance events, ranging from marathon to 24-hour+ events. This value is determined from observational studies of hydration, performance, and incidence of hyponatremia. The low range is for slower, lighter runners; the high end for heavier, faster runners.

It might be worthy to define “thirst.” Clearly, severe dehydration will cause severe thirst. However, those athletes looking to stay ahead of fluid need might consider a similar notion: “If it tastes good, you need it.” Simply put: does water taste good? If so, this subjective assessment might be a more nuanced assessment of fluid need. Whether the converse (an overt absence of thirst, accompanied by a dissatisfying taste and appeal of fluid) indicates fluid satiation or excess, was not addressed by Noakes or his book.

Consumption of roughly 60g of glucose per hour during competition will improve performance.

Noakes has separately researched and reviewed studies on glucose supplementation and determined this value for greatest performance and gastrointestinal acceptance. Values upwards of 100 grams per hour have shown even greater benefit; however, this increasing sugar invites GI disturbance.

Supplemental sodium is unnecessary in endurance competition.

This conclusion, based on his work and literature review, will undoubtedly result in controversy in the ultra community. Noakes is careful to point out numerous studies demonstrating that blood sodium levels are maintained in absence of supplementation and outright deprivation, with prolonged exercise over many days. Moreover, he points out the absence of any study that identifies performance benefit from sodium supplementation; in fact, he points out two studies in the past decade that contradict the notion.

For the sports medicine community, he recommends the following:

Be very careful to make accurate diagnoses of troubled runners.

Runners who come into medical checkpoints, feeling dizzy while standing still on a scale, are more likely to be experiencing Exercise-Associated Postural Hypotension than any other ailment, says Noakes. It is the simple notion that – in that brief moment of pause – a runner’s blood pressure drops due to the cessation of running. The simple treatment is to elevate the feet over the heart, wherein recovery is rapid. There is no evidence that postural hypotension is due to dehydration.

More important is an accurate diagnosis of the hyponatremic runner. An athlete exhibiting the signs and symptoms of hyponatremia – weight gain, swelling, nausea and vomiting, headache, muscle cell breakdown, altered consciousness and seizure – must be accurately diagnosed. Administering a 100mL bolus of 3.0% sodium solution results in rapid recovery in nearly every hyponatremic runner.

Erroneously determining these athletes as “heat exhausted” or “dehydrated” may result in forcing fluid consumption, or the administration of hypotonic IVs. This “treatment” will only worsen the condition, prolong the suffering and recovery time, and in worst case, may even result in death.

* * * * *

For a text so replete with cold facts, Dr. Noakes’ passion for the message permeates the text. Certainly, he is passionate for the sport, being a veteran of the marathon and ultra distance. But elements of personal frustration, and even guilt over having pushed the “drink” message in his early days, are also felt by the reader. Personal accounts of death from overhydration are included in Waterlogged, not to sensationalize, but to better understand how something as innocuous as water, and the good intentions to avoid suffering, can result in deadly consequences.

For this reader, given what has been known – yet ignored – about hydration science for so long, justifies the strength of message. In the very least, hyponatremia can ruin the race day for runners and families. Worse yet, it could end a running career. Or a life.

It is fitting, therefore, that Noakes finishes his text by putting the hard data away and appealing to our common sense, by saying, simply: “Your body will tell you what it needs, if you just listen.”

Trust your body, and it’ll take you places. Just as it has always done for ultrarunners.

If 4,500 words aren’t enough for you, stay tuned to part two of our discussion on hydration and ultramarathons: “Hyponatremia & Western States.” There, I will share additional insights, including:

  • A Q&A with author Tim Noakes, MD
  • My personal account (a “n=1 case study”) of applying Noakes’ recommendations to the 2012 Western States Endurance Run
  • Insights from Marty Hoffman, MD, lead research director for the WS100, and from Kerry Sullivan, MD, medical director
  • What the impact of Waterlogged may have on Western States and other ultramarathons in North America

Until then, here’s to happier, healthier running.

Call for Questions

  1. Have you ever experienced symptoms of hyponatremia during a race? Have you ever been diagnosed and held at an aid station – or forced to DNF – by medical personnel?
  2. What is your experience with fueling (either water, salt or calories) “by feel” versus “by a schedule?”

[Disclaimer: The contents of this column as well as the author’s comments are provided for general informational purposes only and are not intended as a substitute for professional medical advice. Do not use the information on this website for diagnosing or treating any medical or health condition.]

Joe Uhan

is a physical therapist, coach, and ultrarunner in Eugene, Oregon. He is a Minnesota native and has been a competitive runner for over 20 years. He has a Master's Degree in Kinesiology, a Doctorate in Physical Therapy, and is a USATF Level II Certified Coach. Joe ran his first ultra at Autumn Leaves 50 Mile in October 2010, was 4th place at the 2015 USATF 100K Trail Championships (and 3rd in 2012), second at the 2014 Waldo 100K, and finished M9 at the 2012 Western States 100. Joe owns and operates Uhan Performance Physiotherapy in Eugene, Oregon, and offers online coaching and running analysis at uhanperformance.com.

There are 100 comments

    1. soonerred

      I've had sodium issues on many levels. I happen to believe it all depends on your body weight. Ive known heavier runners that tend to cramp and show signs of sodium deficiency more often than this with a lower BMI.

  1. Jess

    I respect the science, expertise, and ability of Tim Noakes quite a bit. But I have a hard time reconciling his advice to 'drink to thirst' and let natural sodium regulation mechanisms do their work with my own personal experience running in humid heat.

    I used to live in a place with hot humid summers, and I suffered through long runs every summer. I learned that drinking to thirst made my stomach feel bursting with water, made me feel so nauseated I couldn't run and could barely walk. I started putting water in my mouth and spitting it out without swallowing, hoping to quench the feeling of thirst without making myself sick. Finally someone clued me in to the fact that salt regulates water absorption, and that the cramps and sickness I was experiencing by 'drinking to thirst' were hyponatremia due to the immense volumes of salt I was sweating out. I started having salt on runs where I sweated more than usual, and suddenly my stamina improved immensely, and I did much better on those summer runs. There are many possible sources of hyponatremia, and while drinking on a schedule is one, drinking to thirst is another.

    I am really pleased that Noakes is challenging running dogma and discussing the actual scientific results. But I hope he is more thoughtful and nuanced in his analysis than most of the discussions I've seen of Waterlogged, which seem to replace one dogma with another.

    1. OOJ

      Jess-

      Thanks for your personal insights!

      What I respect most of Dr Noakes as a fellow scientist – gleaned not only from the book but also my personal discussion with him – is that he sticks to the science. Period. *What does the research really say?* What is actually out there, versus anecdotal experience, or clinical values.

      Indeed, I have my disagreements of things he's said (which will be discussed in Part II) based on my race experience. But that only means that we – as scientists and runners – don't know *everything* yet.

      As for your experience, the research DOES say that water is better absorbed with SUGAR – not salt. Therefore, if you were drinking volumes of water alone, its absorption would've been slower.

      My *personal experience* (again, stay tuned to Part II) is that when I drank enough to "wash down" the 60-80g of sugar/hour, that was plenty of water. And only when it got significant warmer did I experience thirst.

  2. David

    Exceptional piece and great information, thanks! Personally I've stayed away from sports drinks and only consumed water during ultras for hydration, and been a fairly light drinker at that. Guess it makes sense that I haven't had any real issues. And look at someone like Anton – a runner who seems to go out all day in the mountains with minimal water supply. He seems alright.

  3. Cameron

    This is a great article about how a runner's body will handle the demands of running and its associated needs (water/sodium). It makes sense to me that my body will regulate its own sodium level and that my own thirst will guide me toward an appropriate amount of fluid intake. Thank you for posting. I hope the running community will fully embrace Noakes' sound scientific look at the reality of our body's abilities.

  4. Matt

    Very interesting article, indeed.

    I am a big guy who sweats like a pig, even at cool temperatures, and I easily loose 1kg per 10km even when drinking.

    During my long runs, I carry some water but would say that I might be on the minus side in terms of hydration, and I drink when I am thirsty and every km or so.

    I never pee during long runs (longest was marathon) but as long as I keep sweating I give myself an 'ok'.

    Regarding salts, I haven't figured that one out yet. I would normally take only those included in gels and in very (1/4th of normal concentration) diluted Nuun.

    Tried S-Caps and didn't see any difference, to be honest.

    I have never had cramping issues but definitely got dehydrated quite a few times (got very thirsty, obviously), but even then I had no problems with muscles, just fatigue and feeling out of it + a bit raised core temperature.

    Rehydration is always relaxed, it can easily take me 2-4 hours after a long run to pee again, while drinking regularily (no seriously excessive amounts)

    Definitely need to think about this more!

    //Mattt

  5. OOJ

    One thing worth noting – that 4500 words somehow did not touch on – is the notion that, by avoiding hyponatremia, one can avoid one of the most substantial sources of "nasty bonks".

    To reiterate the symptoms of hyponatremia: weight gain, swelling, nausea and vomiting, headache, muscle cell breakdown, altered consciousness and seizure.

    Many of these, notably the less severe, are typically blamed either on lack of sugar, lack of salt, or some other "random malaise". Perhaps the real issue is prolonged over-hydration and hyponatremia.

    I've been hyponatremic in races on more than one occasion (with blood tests to prove it). It SUCKS, and – unlike sugar or water deficits, which take minutes – it took hours to resolve.

    Thus, those looking for more stable performance, especially for longer ultras, might benefit greatly from the lessons of Waterlogged.

  6. Chris

    I read an article…Well, I read part of an article online…NOT THIS TIME! :) Read the whole thing! Wow. Excellent information and I look forward to learning more. This one is sure to hit everyone's beliefs.

  7. Mike Place

    I've just about finished Dr. Noakes book and I think he's dead-on. There are some runners who just can't tolerate the commonly prescribed levels of electrolytes. (Me, among them.)

    For guys like me who are extremely light and thin, eat a low-salt diet and who just don't sweat very much, we have more than enough salt on-board to run for many, many hours without a problem. Personally, I get extremely nauseous and violently ill if I take any type of salt capsule more than every 8-10 hours.

    Kudos to Dr. Noakes for a very brave book that's spot-on!

  8. Mike Hinterberg

    Did Noakes state this, unequivocally?

    "To reiterate: there is zero correlation between frequency or color of urination and hydration, or kidney function. "

    Nominally, pale urine is still very much a sign of euhydration and health. The literature abounds with this in many contexts, but I believe that we're *only* discussing endurance exercise here.

    In the context of endurance exercise and rehydration, I believe one of Noakes' sources is this:
    http://www.ajcn.org/content/92/3/565.full
    (Thankfully free access!)

    Limitations of urine colour tests are noted, including subjectivity.

    What was not analyzed specifically were the *extremes* — does the lightest urine generally represent health? Does the darkest urine generally represent impaired kidney function, with new insights suggesting that it could be /either/ hypo- OR hyperhydration?

    In other words, when is very dark urine *not* a sign of hydration status or kidney function?

    Rather than throwing the baby out with the bathwater, so to speak, I'm suggesting that a more discrete (rather than continuous) use of urine colour analysis, based on extremes, is still a very useful tool for assessing health status. And I agree that diagnosis and treatment should include consideration of body weight change. Comments?

    1. David

      I think that some runner foods are laced with vitamins and will cause dark urine color even when there seems to be a lot of urine production-as when drinking a lot

      otherwise I would think dark urine could mean something such as muscle breakdown or dehydration. Possibly a subtle difference in the color of the dark urine depending upon whether it is just B vitamins or heme/muscle breakdown products?

  9. OOJ

    Mike-

    Excellent points, thanks for the comment.

    Because ADH decides fluid loss via urine, it is entirely possible to be significantly *over-hydrated* (intra- or extra-cellular), yet produce dark, low-volume urine, due to ADH telling to kidneys to conserve. The great mystery is why, in some people, is ADH produces in excess during exercise – or at times when the body is overhydrated/hyponatremic.

    Therefore, your kidneys may be fine, your hydration perfect, yet you produce no urine. I know of one ultra runner friend who went the entire Bandera 100k (>8hrs running) without urinating, without issue.

    This "big picture" is that we cannot rely on a single data point to determine any diagnosis of hydration level, which you accurately point out. :)

    1. Ben Nephew

      Vasopressin has a number of functions other than fluid balance. One role which may be relevant to this issue is as a mediator of the endocrine stress response. High plasma levels of AVP are found in patients suffering from chronic depression, anxiety disorders, PTSD, and schizophrenia. It is possible that some runners have an overactive AVP response to the stress of racing. I'd be curious to know if runners who produce an excess of AVP also are more likely to have GI issues.

      I'm not sure telling people that there is zero correlation between frequency or color of urination and hydration, or kidney function is helpful to ultra runners. While rhabdo may not be an epidemic in ultrarunning, it still seems too common. Someone with dark urine thinking that it's not a problem is probably not good. In terms of runners going for long periods of time between urinating, I don't think there is enough long term data out there to know if this causes long term kidney issues or not.

      1. OOJ

        Ben-

        Thanks for the insights! The additional info on ADH is noteworthy, as that is a plausible mechanism for high blood levels in spite of A.) adequate/excess hydration, B.) cessation of running (e.g. walking, or sitting at an AS), yet still not producing urine.

        What I predict we'll see coming from the research is a relationship between rhabdo and hyponatremia; again, excessive water causes muscle cell lysis (destruction).

        Dr Marty Hoffman posted a case study from the 2009 WS Run where five of the 41 subjects had both hyponatremia and rhabdo. The predisposing factors for rhabdo in this case study were 1.) running fast, 2.) having an injury during training, 3.) use of NSAIDs.

        *Adequate* hydration is important in *treating* rhabdo; however, hydration will not prevent it – in the presence of lack of "quad seasoning", aggressive racing, and NSAID use.

        On a side note, we're also beginning to learn more about ibuprofen's role in: 1.) muscle cell damage and 2.) vasocontriction of blood vessels within in the kidney.

        Again, Ben, the over-arching theme is this: rely on more than one piece of data. Dark urine alone is not sufficient data for any assessment. Dark urine PLUS muscle pain PLUS kidney pain PLUS weight loss PLUS thirst would – from a medical perspective – be adequate data necessary to diagnose rhabdo, requiring additional hydration

      2. HeatherW

        If thirteen percent of runners in the Boston Marathon had abnormal levels ADH/Vasopressin, this probably extends beyond runners with PTSD and schizophrenia. My understanding was that there is a wide variation in regulation and response to vasopressin in the population. If so, perhaps SOME of us (maybe that 13%?) will still benefit from using electrolytes while running. Perhaps it is too early to scrap the recommendation to "try what works for you".

  10. cory feign

    wow thanks for the thorough recap. we might as well throw religion and politics into this conversation. gonna check out the book now and test out some strategies to see what it's like. i currently use saltstick every hour for long runs, so will be interesting and a change of pace.

  11. Dax Ross

    What would Noakes say about craving salt (salty foods) during longer events. Isn't this my body telling me it needs salt in the same way that thirst is my body's way of telling me it needs water?

    1. OOJ

      That's a good question, Dax, that I'll pass along.

      I've used this as a way to assess salt need – I will break an S'Cap in my mouth. If it tastes *good*, I "know" I need it. ("Know" being used loosely, given the research outcomes).

  12. Lucho

    Awesome! So the idea that beer is a diuretic doesn't matter!? ;)

    Noakes also said that taking sodium does have a powerful placebo effect that is beneficial. If you think you need to take sodium then do it. The take away that I get is that you need to do what feels right to you (IE: drink to thirst) and listen to our body. But don't panic if you miss an aid station or drop some S-caps. Our bodies are smarter than us in terms of survival.

    1. OOJ

      What's MOST interesting, I think, is the psychology of thirst and drinking. Noakes touched on this briefly. Seperately, Dr Noakes is known for his work on the "Central Governor Theory", where the brain decides how hard we can run, based on the info (race length, temperature, terrain, competition).

      That said, if the brain perceives benefit or relief from ingesting *anything*, a psychological benefit will then be *felt* – regardless of its physiological effect.

      There are some studies out there that show this: one that comes to mind was a study where three groups of runners were tested:

      1. Running + drinking electrolye drink

      2. Running + only swishing (NOT ingesting) electrolyte drink

      3. Running w/no fluid.

      Groups 1 and 2 had equal performance (statistically), and better than the control. There are more studies out there like that; I'll try to find them.

  13. KenZ

    Thanks for the great summary. Got the book on my desk, but haven't had time to get past the first chapter.

    I've always popped S-caps religiously, since, well, that's what everyone says to do. And I'd pop extras when I'd cramp or start to feel the cramping coming on. After a few years of it though, I definitely figured out on my own that my cramping was muscle fatigue and not affected/solved by electrolytes; I'd just have to down-regulate my pace/effort a tad, and can that way stay right on the "cramping edge," for hours, which thus effectively becomes my performance limiter for longer events (in the first several hours, I regulate by heart rate which works great).

    That said, I STILL took S caps religiously. You know, because I'm supposed to. Luckily, S caps weigh (and cost) next to nothing compared to the rest of the gear. If this work was published by anyone other than Noakes, I'd perhaps be a bit more skeptical, but this book definitely gives one pause. This summer I'll probably do some experimentation to help convince myself that all this is true (because I'm stubborn… a common trait amongst us).

    I will note, however, that his water intake recommendation ranges and glucose levels are generally on par with what most ultrarunners seem to advise, so no changes there for me; I'll just do a bit more fine tuning with thirst, but I've found that thirst generally agrees with the advice.

  14. Steve Desmond

    I ran my first ultra last fall — all I consumed was a PowerGel and 200-400mL of Gatorade (diluted to 50%) at each aid station, whatever I felt I needed. I finished 2nd, right around my goal time, and with the exception of a sprained ankle recovered pretty quickly.

    I didn't urinate until about 10 hours after the finish, but I'm used to that post-run and never really thought of it as a problem (though many do) — now I know the science behind it!

    Thanks for the cool article,

    -Steve

  15. JKal.

    Did a 50 mile race last summer, my longest distance ever. At mile 40 I experience a huge muscle cramp in my right calf. staggered in to aid station at mile 41 limping. Up to this point I had Gu, gatorade, coke, water, and more Gu. At aid station i had TWO salt packets. Within 2 minutes my cramp was gone and I finished the 50 mile race without incident. One case, i know, does not change the data given in the story, but it did happen to me. I'll stick with S! caps or salt packets at aid stations in the future!

    1. OOJ

      JKal-

      Thanks for sharing your experience. Allow me to play Devil's Advocate a bit for your case, if you will.

      Based on the research presented by Noakes – and my clinical experience as a physical therapist who does a lot of running gait analysis – the top reason for muscle cramping is "mechanics x load". If load is too great AND mechanics flawed, you will cramp. Noakes found that: faster pace = cramps.

      What the research had yet to quantify is biomechanics (very hard standardize). From my professional (and personal running experience), calf cramps come from landing in front of your center of mass = braking forces. Doing so for 41 miles will quite conceivably cause cramping.

      My questions for the "science" of your case are:

      – Do we know if you were braking in your stride? (Those who ran the 2012 WS Run might; a research study on landing mechanics was conducted, at miles 10 and 56!)

      – What affect did simply STOPPING at the AS have on your cramps?

      – Upon resuming your run, did you adjust your pace? Or your mechanics?

      Again, I'm only playing "Scientist's Advocate". I've personally sung the praises of salt; yet I've also found THE #1 cramp prevention is avoidance of braking during the running stride.

      1. JKal.

        in this race it was "hilly" for michigan, but not extreme in any way. I can only think of 2-3 instances where i was going down a hill for maybe 40-50 yards and had to really put on the brakes to slow down.

        Yes, simply stopping for 30-40 seconds at aid station may have helped and yes, i probably slowed my pace just a bit for a while after leaving aid station. So, could have been the salt or could have been the slower pace/rest at aid station.

        I will say that the salt tasted SOOOOOOOOOOOO good when i popped the packets in my mouth!! It was a fairly nice day 65 at start up to 74F by finish, 100% shade so i really didnt lose a lot of salt to sweating i'd bet.

  16. Alex from New Haven

    I've always drank a lot on long training runs and races… and I think, in retrospect, a little too much, mainly because I was trying to get a lot of my calories from sports drink. As I've been in the sport longer, I've gotten more comfortable with going longer periods without calories, salt or even water. I think much like intense effort, the brain learns over time that "you" know what you're doing and that "it" doesn't need to panic.

    I still find the transition from 60 degree Spring days to 90+ Summer days, that it takes some time to re-norm on what the right amount of drinking is…

    One thing that's not 100% clear (to me) from this is the difference between what's "necessary" and what "optimizes performance" and that may not be known.

    On a broader note: I feel like a lot of things in the food/nutrition world are totally Topsy-Turvy. I grew up in the 80's when FAT WAS BAD and in the 2000's when everything could be FAT-FREE, and now it turns out that sugar is bad and there are like 5 different kinds of fat and some are good… and now even ultra nutrition, electrolytes and even vitamins are getting turn on their heads… in 50 years we're going to look back at the last 4 decades and LAUGH OUR ASSES OFF.

  17. Julie

    I have not read the book yet, but I will. Did read the article and while I can see the science in much of what is being said, I also agree with some of the commnets. I run Ultras, and am slow. I have had rhabdo, and suffered from both hyponatremia AND severe dehydration in my running career. I also sweat more than the average person. What I disagree with most here is the whole idea of *ignoring* your urine output/color and the fact that losing weight during a race is ok. Perhaps in a marathon you could get away with that, but in an ultra? I can lose 5-10lbs on a 20 mile run if it is warm and/or humid. That loss would have me pulled at a med check in an ultra. And, that is WITH me consuming 2+ liters of fluid and taking SCaps (over a 4 hour period or so of time) Not drinking enough, when I was forced to conserve water on a 90 degree day caused me to become severely dehydrated, my kidneys shut down, I lost over 12lbs sweating and ended up in the ER with my electrolytes out of whack and Rhabdo. So, though this info might be ok for the average, general population, I do NOT think it is a one-size-fits-all. I do drink to thirst, and it isn't enough. I simply cannot keep up with my loss that way.

    Urine color IS a good indicator of hydration AND impending issues. I would not ignore urine output and/or color during a race (my ER experience was preceeded by 8hrs with NO output…that is NOT normal or ok…was several more hours and several liters of iv fluids to remedy that)Our bodies have systems in place for a reason, and though running ultras may not be *normal* that does not mean your body should not still function normally. If your kidneys do not continue to do their job, you run the risk of problems that are potentially going to land you in the hospital…to say it is ok to go many housr without any urine output…eh, not advice I am going to take to heart.

    We are all an experiment of one, and need to do what works for OUR own body. I hope this book doesn't lead to people thinking they should forgo drinking enough and using electrlytes…because for some, it IS necessary. Hmmm….

    1. OOJ

      Thanks for sharing, Julie.

      Some comments:

      >What I disagree with most here is the whole idea of *ignoring* your urine output/color and the fact that losing weight during a race is ok.

      To reiterate, urine color *alone* is inadequate information to determine hydration status, given its lack of correlation to hydration level/blood sodium. *However*, urine frequency/color PLUS thirst PLUS significant weight loss would be adequate. The message is, do not rely on urine color alone.

      A notable example of this was running with a friend of mine during a 100-mile race. He was quite worried about having not peed in a long time – and then peeing dark urine – *despite* consistent data that he was gaining weight, had swelling of extremities, and had early-onset hyponatremic symptoms. He continued to drink. He finished the 100, but was hospitalized for hyponatremia and rhabdo.

      >I can lose 5-10lbs on a 20 mile run if it is warm and/or humid. That loss would have me pulled at a med check in an ultra.

      The question here is, "Why?". And, "What are med checks doing now?" These questions will be addressed in Part II. It's notable that, as of a few years ago, the Western States 100 is done away with its "3-5-7% Rule" at aid stations. Again, a single data point – 5-10lb lost (3.3-6.6% for a 150lb runner) – in absense of any other symptoms – is not cause for concern for either a runner or med staff at most 100-mile races today.

      >Not drinking enough, when I was forced to conserve water on a 90 degree day caused me to become severely dehydrated, my kidneys shut down, I lost over 12lbs sweating and ended up in the ER with my electrolytes out of whack and Rhabdo.

      I'm sorry to hear about this. I'll reiterate Noakes' message: that "drinking to thirst" and self-regulating pace in heat will ensure safe completion of even the most extreme (distance, duration) events. Based on your account, you did not drink to thirst if you were "forced to conserve".

      What was your strategy, post-run, to rehydrate? Given the research (prolonged exercise/fluid loss = increased blood sodium concentration), I find it notable that you had abnormal electrolytes after this run, unless you had over-hydrated, post-run.

      What was the distance and pace of the run? What was the terrain? Was your training adequate (for muscle tissue) to handle this run? Did you find yourself "rushing" to finish the run, given that you were low on fluids? Did you take any NSAIDs before/during/after the run?

      To reiterate Marty Hoffman's latest paper (http://ws100.com/medresearch/Bruso-et-al.-WEM-2010.pdf), it was injury/lack of preparation, pace, and NSAID use that predicated Rhabdo.

      >my ER experience was preceeded by 8hrs with NO output…that is NOT normal or ok…was several more hours and several liters of iv fluids to remedy that

      Do you have any idea what your blood ADH level was? What about your blood urea nitrate levels (BUN)? I'd be most interested in knowing if you had elevated ADH (=water retention, despite "liters" of IV) and/or elevated BUN (=decreased kidney function). Do you know your approximate urine volume once you began to produce? If it was high (e.g. "liters"), I would suspect the inability to urinate would be due to either elevated/persistent ADH or mild kidney compromise – not clinical dehydration.

      We *are* an experiment of one; however, we must resist the urge to rely only one one (or few) pieces of information. Urine output and color is but one piece of a larger puzzle – in racing and training.

      1. Julie

        Here is a blog post I did right after the race I was refering to… http://rawveganrunner.blogspot.com/2010/07/vt-100
        I do believe Iwas trained and prepped for the race, this issue I have had with sweating/hydration has been ongoing for much of my adult life. Wasn't an issue with shorter distances(though I got hyponatremia during a 13m trail race and a marathon)but now…seems worse. I appreciate your responses, as you are the first person who has actually offered any sort of response to my issue! (trust me, I have asked a LOT of people/doctors)Unfortunately I do not have my labs anymore, but I know I had rhabdo and hyperkaemia. Normally I do drink to thirst, however it still does not seem to be enough. I Keep myself adequately hydrated normally and I will drink a diluted sport drink(ultra by Succeed) after my long runs until I have adequately rehydrated. I did not take any NSAID's before or during that race. A side note, I do have Hashimoto's and Lyme Disease…I have often wondered if the Hashimoto's had anything to do with it as I have a hard time regulating my body temp as a rule…but I run cold, not hot. I am an enigma… :)

  18. Aaron

    "Moreover, some cases have shown insidious spikes in core temp, hours – if not days – after cessation of exercise and onset of treatment." This would happen to me frequently back in the days when I combined thermogenics with very high intensity intervals. Any stimulus like a bit of exertion, even just walking in mild weather, would send me into a sweat drenched hot flash.

  19. Alicia

    I think Noakes is a great scientist and can't wait to finish the book. One question that immediately came to mind was that the forward (written by someone else, not Noakes, so possibly not representative of what Noakes is saying) refers to the body being well-equipped to deal with "transient dehydration, which lasts from 4 to 8 hours." I also noticed a lot of references to research done using Comrades runners. Would there be any change in Noakes' conclusions if the event in question is much longer, like mountain 100 milers or Badwater?

    Another question about the relationship of frequency of urination and hydration. At Leadville last year I had lost 10% of my body weight at mile 60, so I think it'd be safe to say I was dehyrdrated (I hadn't been drinking much and had vomited a fair bit). I also hadn't urinated for about 13 hours. Since neither of those things have ever happened before or since, I find it hard to believe they're not connected–maybe it's that the connection between the two works in a different way to how we've previously thought?

    I was slightly disappointed when I got to the conclusions about the appropriate amount of water to drink, since I rarely make it past 500mL an hour anyway! Still, interesting conclusions about the electrolytes and muscle cramps…

    1. OOJ

      Alicia-

      Noakes cites several studies covering long-ultras, including 100s, and 24-hour races. He also cites several multi-day, exertional salt-deprivation studies to substantiate his recommendations.

      "Hadn't been drinking much" + "vomiting" is definite cause for dehydration. An interesting notion is: "My weight is down. But I'm nauseous and vomiting…so I'm not 'thirsty'…". Therefore, drinking to thirst may not work in that case…

      1. Alicia

        Good to know, thanks. I personally think a bit of an edit for that part of the forward could be useful, since it was the first thing I read and it left me wondering whether the book was going to be relevant to me or not.

        Yeah, the nausea/vomiting issue sounds like a big problem with drinking to thirst in the longer races. I noticed Noakes says "If at any time a healthy athlete does not sense thirst, the athlete is not deydrated. Period." I know I wasn't thirsty when I was 10% down on body weight. That leaves the word "healthy" as an all-purpose exception which would appear to mean that a runner who has nausea and vomiting isn't healthy (I'm not aware of any way in which I was unhealthy at the time other than nausea and vomiting). But would that make the exception encompass a huge percent of ultrarunners and pretty much swallow the rule…?

  20. ultrarunnergirl

    Great information. Hubz has been reading a lot on the sodium and cramping issue lately — he has been skeptical about the link between the them for years now. It makes perfect sense – neither of us seem to cramp on training runs, no matter the heat or distance. It's only happened during races where you're really upping the intensity and pace.

  21. Paul Barbier

    I am fairly new to longer distance running having done the odd marathon, and now 40 miler and once I did a 115km trip along the coast at home. I have found that I seem to need a lot of salts / rehydration fluids to stop cramps and maintain my body feeling energised, along with a broad variety of food stuff from gels to ham and cheese rolls… Training in heat really seems to affect me badly if I end up feeling badly thirsty. I drink to thirst, but sometimes woonder if my thirst is not a psychological thing that may be less related to performance and running well than I imagine. This springs to mind especially when I have many friends who run better /longer or faster than I and consume less liquids….

    I think maybe they help me recover better…

    The article is really interesting and prompts me to experiment in drinking a little less and taking in a bit less salt to see how it feels. I always thought that all that white salt crystal stuff that i get covered in from sweating was causing a deficit, not indicating a surplus!! Fascinating indeed, I look forward to the next part of the series…

  22. Kevin

    Think about all of the things that had to happen for people to arrive at our place in the universe. There is no way all of this would produce something fragile. But somewhere along the line, we got the idea that our bodies are inherently flawed and that shoving salt and Gatorade down our throats was better than listening to what our bodies are trying to tell us.

    1. Ben Nephew

      The modern human is becoming further and further removed from normal selection pressures. Many of us would not be here without modern medicine. Compared to many other species, we are quite fragile. The rationale that we are still significantly affected by normal selection pressures has been problematic with respect to the recent trend of minimalist shoes.

      To assume that thirst is an absolutely accurate indicator of need for hydration seems similar to the assumption that we were all born to run in minimalist shoes.

      For hydration in ultras, nausea is a huge confound to the relationship between thirst and hydration. Has anyone documented the prevalence of nausea at 100's?

      1. Kevin

        Even if we were being removed from natural selection, would this change the structure of our feet and alter the way our body is hydrated?

        Name an animal that is a better endurance runner than a human, then ask yourself if we are fragile. Remember that this article is about running, not all the other things that can hurt us.

  23. Fernando N. Baeza

    Dear Julie,

    I normally sit out on postings like this as they are taken subjectively, but I do so value articles such as these as we can see the two sides of the same coin. I am also a clinician, albeit, not a PT(like awesome OOJ!), but a clinical biochemist. I work in a private practice. I see patients and routinely perform 3 to 4 urinalysis minimally per day. What Im about to state is simply an observation made by me; I am not adding or taking away from what Mr. Uhan has written about. Ive seen very dark urine and Ive seen very light urine. Much of the dark urine Ive seen is because the patient has "fasted" and understood the bloodwork could not be read effectively if ANYTHING was consumed, including water–so the patient did not drink water. Usually patients with dark urine have a higher CPK level than normal, high protein levels, blood and leukocytes–meaning a urinary tract infection, not necessarily a sign of dehydration. So theres a big question mark here. When running 4 to 5 hours, my water consumption is also minimal, although my sugar intake is high with gel consumption every 30 minutes. On the other hand, on shorter runs I dont take any water or gels period and this brings alot of criticism from my ultra buddies. In my opinion, if I may be so bold to say it, is that in my mind its all psychological…did I just say that?! Physiologically my body doesnt ask me for any of the sugar, or water, for instance, but I do it anyway. Could I do without it? Id have to say yes. The demographics on patients I see with clear urine are young, fit individuals, or should I say "nonobese." But they also exhibit higher ptrotein levels. So as science advances so must we. Its good to see a different perspective. That can only further any cause–seeing two different sides. :D

    Respectufully,

    Fernando N. Baeza

    1. Julie

      I should have been more specific in my post…I do understand that basing ones judgement on urine color alone is not a good indicator of where one is at physiologically. I just meant that to NOT include that in your evaluation of where you are at would be foolish. You need to look at the overall picture, which I think we all agree on. :) I am an oddity in races as I am not using NSAID's, a slower runner who sweats VERY heavily, yet I am not overweight, undertrained, etc. I can drink to thirst but it is not enough to stay ahead of my loss. Even when I am NOT running, I would bet my *output* is not normal, and has never been *clear*…I guess my posting is one, for my own search for the *why* in my personal case and two, to say we all don't fit into the nice neat box that the author is putting out there and though his way of hydrating and fueling may work for some or even most, it is not going to work for all and I hope that people read his book and take the info and see what will work for them, and what won't and not blindly follow. :) Thanks for your comment!

  24. Peter Curtis

    Dear All

    I find all of this stuff very interesting. This along with a talk we had at work the other day on trying to eat more like a caveman / woman, starts to make you ask a lot of questions about our modern diets.

    A few things that have not been discussed that would seem sensible in the context of the article and book are:

    1. I drink when I get a headache as through high altitude mountaineering I have always found this to be the best indicator for me, of when I need to drink. I have found that a headache comes on a long time into exercise and agree that we probably all drink too much in these modern days. Just ask your grandma how much water she used to drink as a kid and I bet it is far less than nowadays. A lot of our desire for water intake is brought on from working in air conditioned offices that dry our mouths out and make us feel like we should drink.

    2. Fat releases a lot of water as it is broken down. I would be interested to know if people who follow a true "caveman / Paleo" diet find hydration different to people who predominantly rely on carbohydrates for fuel. This would be interesting to see over a long distance.

    I can safely say that our ancestors would not have had the same kind of access to salt that we have, so they must have survived with much lower levels in their bodies, otherwise they would not have caught up with tha animals they were chasing and wouldn't have eaten.

    If you have seen the persistence hunting clip on you tube by David Attenborough, you will see the hunters are out for about 8 hours and only have a small water bottle to drink from.

    http://www.youtube.com/watch?v=826HMLoiE_o

    It might just be possible that through the way we now live our daily lives we train our bodies to work in different ways than our ancestors used to. I am sure over time it would be possible to reduce your bodies reliance on water intake and carbs, and this may just result in better performance in endurance events.

    Peter

  25. OOJ

    Good additional info! With the presence of both Hashimoto's (thyroid/metabolic) and Lyme (neurological), we might as well "throw out the playbook" on more typical, predictable response of these systems with extreme exercise. Thus, knowing one's own body becomes all the more important.

  26. OOJ

    This also brings up another "nuanced" view: the idea between physiological need versus optimal performance.

    I feel that, with profound dehydration, even the nauseous ultra runner will eventually experience thirst. But that is different from optimal, consistent performance.

    That said, as I've mentioned before, the idea of "if it tastes good, you might need it" *could* apply. It was very cool to actually have water still "taste good" at the end of the WS this year.

    As for healthy, I believe Noakes was trying to imply that a runner without other pathology (see Julie above) should reasonably expect to experience thirst only when there is a physiological deficit of water. Being nauseous and vomiting doesn't imply "unhealthy".

  27. Cary Stephens

    This article (and the conclusions of the book) are quite interesting to me at this time. I have been a runner since age 9 (now 43) and have competed for most of those years. My problem is severe nausea. Beginning back in 2002, while training for an Ironman, I had my first really bad case of nausea late in a 100 mile ride in hot weather. My goal was to take in 250-300 calories per hour in gel form, so fluids (like 20 oz per hour were needed) but I would say I hydrated mostly by thirst. I got extremely sick and the nausea lasted for several hours. I attempted the Ironman a few weeks later, but had no real idea what was causing my problems. Again I mostly drank to thirst. It was a disaster of vomiting proportions. Nothing seemed to be passing through me after the first couple of hours on the bike. This problem has plagued me on long races, training runs and rides (over three hours) ever since. When sever, the symptoms can take 6-8 hours to resolve. Back then, I was not focused on salt and not focused on hydration, except to keep the fuel concentration between 7-10%. I had no idea what my sweat rate was. After years of experimenting with many different fuel sources and amounts, different hydration plans and walking strategies (ones that were integrated into the fueling and hydration plan), I was making only limited progress. I was still getting sick quite often. So, this year instead of quitting, I decided to have my blood tested to see if I had any other problems that could be seen. Nothing was out of the normal range. I asked my doctor to test me again immediately after a 4 hour training run when I was mildly symptomatic. Running to get sick on purpose is hard!! Again everything was within the normal range, but my salt was low in the normal range. I had lost 5 pounds even though drinking 22 oz per hour on a cool day. I am now striving to reach my well calculated 30+ ounce per hour sweat rate, usually being 6 ounce per/hr short, and I drink a larger volume (16 ounces) during a 10 minute walk break–thinking that the lower stress load will help my gut process. I also added more salt (now 500 mg. of sodium per hour versus 200 mg. before). Based upon this strategy I finally finished a 50k this spring without serious nausea. While I am zeroing in on what my body needs, it truly is an experiment of one. According to his article, Dr. Noakes' book runs smack into my current strategy of not just listening to my body. Interesting. For me, a bit of forced hydration seems to push the water through so to speak. Salt might also be helping me. I am still testing. If I just go out and run, drink when I am thirsty, my gut will shut down, and I will get sick.

  28. Ben Nephew

    Natural often acts on morphology and physiology. There are significnat gender differences in how vasopressin works in a single species. There are species of voles that have huge variations in vasopressin activity based on differences in environment and social structure.

    If ultrarunners were still exposed to normal selection pressures, most of us would not survive. You have to survive to run. Think of the range in speed and performance in a herd of water buffalo. Guess what happens to the individuals who are slightly slower than the rest of the herd. Now think of the range in speed and performance at a typical ultra.

    Many predators survive on prey that have better endurance, they are just faster.

    I would not have lasted 24 hours without modern medicine. Even if you ignore the survival issue, I was born with tibial torsion that required a full leg cast for 6 months.

    1. HeatherW

      Sounds like evolution worked perfectly for you, Ben. There's strong evidence that both [i]Homo erectus [i] and Neanderthals cared for their sick. It's been a long time since our relatives simply threw the slowest members of the group at the predator and ran away. Our complex social structure is very much an evolutionary adaptation.

      I'd argue that the modern environment may even be MORE challenging than previous environments in terms of regulating electrolytes and body core temperature. Yesterday, I woke up in an un-air conditioned house, went to an air-conditioned workplace, ran 6 miles in 90 degree heat, returned to work and spent 20 minutes working in a room chilled to 4 degrees C, and then I got in a hot car (120 degrees F?), which I was conscious and alert enough to operate. My body not only needs to adapt to the change of seasons, but it needs to be able to respond rapidly to "changing seasons" throughout the course of one day. I have a friend that has a child that cannot properly regulate his body temperature or sweat, and they are rightly concerned that he may not make it to adulthood (but they are caring for him anyway because that's what hominids do). I don't think we've changed our environment in a way that removes the selective pressure on electrolyte balance and body temperature.

      1. Ben Nephew

        The care that our ancestors expressed was probably not that effective compared with modern medicine. The point is that our social structure has allowed for the survival of individuals with a greater variability in genotype and phenotype. Selection pressure does not need to be removed, a slight change in selection pressure can have significant effects. This means that the assumption that electrolyte and body temperature systems are responding optimally many not pertain to many people.

        Humans are capable of changing our environment enough to have major effects on all sorts of selective pressures, on both humans and other species. I'm not sure why electrolyte balance and body temperature would be immune to these effects.

        Look at the variation in the renal response to NSAIDs in runners. Who knows how this developed, but it is clear that some individuals can tolerate very high doses and have no renal issues, where others develop rhabo at much lower doses. A review of the literature would reveal that NSAIDs are very safe for the majority, just like most runners can rely on thirst for hydration.

  29. Josh White

    This is not a completely true statement, and a bit dangerous. In patients with SIADH, there is zero correlation between hydration status and urine color/volume. In a normal person, color and volume very closely correlate with hydration status. Run down to your local bar and do a survey amongst those taking lots of "fluids" … how often do you pee and is it clear or not? Granted, alcohol is a mild diuretic, but not so much to have a big effect. The data cited in the article clearly state that 13% of the runners in Boston Marathon had SIADH. Therefore, 87% of the runners did NOT have SIADH. Thus, 87% of the time, urine color and volume is a decent way to estimate hydration status.

    1. OOJ

      Josh-

      Thanks for your point of view.

      The only danger is relying on a single point of data to make a diagnosis (either medically, or in performance). Determining hydration status (or kidney function) based solely on urine color and frequency – during exercise, with the prescence of elevated ADH of varying degrees – is dangerous, when you fail to take into account other data: perceived thirst, weight, swelling, nausea, headache, altered mental status.

      The diagnosis of SIADH is made with clinical lab values that reach a numerical threshold. Noakes has a particular defined value (that escapes me now; the book is not with me). Internet sources peg it at Sodium <135 mMol, and blood plasma Osmolality <270 mMol.

      That said, in the 83% that fall out of that range may still be quite succeptible to hyponatremia, given that "normal" sodium is 140-145 and plasma 275-300.

      Because we all secrete ADH during exercise – and every person's tissues are differently sensitive to hormonal secretion – we ALL should be wary of relying on *a single point of data* (pee) to determine any course of action during endurance activity

      1. OOJ

        Side note: Noakes discusses (at least once, possibly twice) the ocassion of drinkers who develop "water intoxication" (e.g. beer-based hyponatremia) from drinking too much beer, too quickly – pointing out that even non-exercising beer drinkers can be succeptible to hyponatremia.

        Guess they should be drinking microbrew… :)

  30. Josh White

    OOJ – it's important to remember that SIADH is uncommon. It's very dangerous and simply incorrect to say that there's NO correlation between volume status and urine. Sometimes, and infrequently, there's no correlation. 13% of the Boston runners cited in the article. Thus, if you ignore your urine color/concentration, you'll be wrong 87% of the time.

  31. Aaron Sorensen

    I would love to see just how far everyone would get if all the runners in Badwater could only consume 400-800 milliliters of water and 60 grams of glucose. I don't think there would be a single finisher unless they walked the whole thing.

    Okay so the rest of the article was very interesting but the BS Flag is up in a big way on the side of sodium intake.

    What is not mentioned is how your stomach and bladder react while only drinking water while running in warmer environments and how the balance of sodium is so important in the way your body holds on to and gets rid of that water you intake.

    I can prove this article wrong about sodium intake on any of my long runs over 25 hilly miles any day. There have been a few times I have forgotten the electrolytes pills and have been right on the verge of cramping up or have to slow down not to, where as utilizing electrolytes gives absolutely zero leg cramps what so ever. I have even gone over 50 miles with almost 25K of gain with zero cramping (2 laps at Barkley). The ones out there that were lacking sodium would immediately start cramping until they had the correct balance back in check. There is no way in hell I could have done these two laps without cramping without electrolytes.

    At least I don’t see any reasonable ultra runner that would actually adhere to this as they should have already proven it wrong as well.

  32. Rhea

    This is a great review of the book and definitely took me by surprise. I've been spreading the dogma of salt pills ever since symptoms of hyponatremia made for a miserable ultra. Now, I realize I need to be more careful in what I tell people, thank you. I want to read the journal articles cited to understand more about what these conclusions are based on: how much individual variability there is in results, what are the sample sizes and what population do they sample, how they apply over various timescales, distances, what other factors complicate the conclusions, and what are the major sources of uncertainty. In science broad simple generalizations are hard to come by and hard to prove in any absolute way, though it sounds like there is much more conclusive research on this topic out there than I realized. Such interesting ideas! I am skeptical, but intrigued. Thank you writing this, I look forward to Part II.

    Without having studied the research, this prompts a few questions. If you drink the right amount, I understand from your article salt pills are unnecessary, most people's bodies will regulate blood sodium levels. Is the blood sodium concentration the only/most important parameter? How long does the self-regulation process take when sodium concentrations are depleted? Consuming the same amount of salt in pill form doesn't help someone who is hyponatremic as well as IV for some reason, but does it help at all? Do higher levels of consumed salt benefit the hyponatremic person?

    If you drink beyond thirst a bit, is the over-consumption of liquid only counteracted by a response of the body to hold onto salt, and any salt you eat is irrelevant? If this liquid consumption is coincident with eating an appropriate amount of salt, does it have no impact? Or do you absorb the consumed salt thus preventing the salt conserving action? Either way we would conclude it doesn't matter if you consume salt or not. But, say the liquid consumption was beyond the maximum salt conserving mechanism ability, it would then be important whether consuming salts would help or not. If you can perturb your body into a hyponatremic state, a state in which a person can move from self-regulation towards a catastrophe model scenario, why would consumption of other things besides fluid have no impact? I would expect a self-regulating system to accept aid. Unless there is no/a weak pathway for ingested salt to affect blood sodium levels on a helpful timescale. I also expect that a self-regulating system suddenly introduced to new harsh conditions (such as high humidity and temperatures after training in cool dry conditions) to be imperfect.

    Are most ultrarunners drinking excessively and not getting into trouble because of sodium intake? Perhaps a false statement, perhaps most just aren't overdrinking severely enough to overwhelm the conservation of salt reaction, but I wonder… If salt actually helps prevent hyponatremia (which it sounds like no study mentioned found any use to salt besides as IV for those in trouble already, but many individual experiences seem to correlate consuming salt with things going better) and we can rid ourselves easily of excess salt, is there any harm in continuing this particular dogma of taking salt regularly during ultras?

    A related question I've had for awhile: are there consequences to eating too much salt during an endurance event? Can we regulate just about any amount of salt and get rid of the excess or is there some health or performance impact to processing an excess of salt on a particular day?

    I like the idea of drinking to thirst, but as others have mentioned it seems incredibly subjective and could lead to wildly different results among individuals. I would think I might feel thirsty because I've come to expect water at certain intervals, not because I necessarily need it. There are plenty of cases where the body does a bad job of self regulating (e.g. autoimmune disorders, cancer, etc.), so I doubt every body regulates sodium levels especially well under the stress of endurance events. But perhaps that is just the catastrophe model talking.

    Interesting article! Thanks!

  33. Alicia

    Hi Joe, I've had time to read a little more of the book and have one more question, about kidney function. If there's any chance of asking Dr. Noakes about this issue in your Q and A I would really appreciate it.

    I was reading what he says in note 2 on page 45, about the female Comrades winner:

    "She chose to drink very little during the race in which she lost 5kg or 11% of her starting body weight. She did not pass any urine for some hours after the race and showed evidence of transient acute renal failure that recovered partially after she had received 2 L of fluid intravenously. Evidence for continuous mild renal dysfunction was present for the 14 days after the race at which she was studied."

    and then compared this to what he says in note 2 on page 336, about the 2007 position:

    "…kidney failure [in addition to rhabdo] may also be associated with dehydration whether or not there is also rhabdomyolysis. As for all these associations, there is no scientific evidence that the relationship is causal. Rather, the finding that all these conditions–heatstroke, rhabdomyolysis, and kidney failure–occur so infrequently suggests that they must be due principally to an individual susceptibility that is exposed by the exercise, plus other environmental triggering factors, which are currently, unknown."

    Could Dr. Noakes clarify, then, whether he meant to imply in the note on p. 45 that the runner's dehydration had any causal connection to her transient kidney failure? If not, what is the reason for mentioning that she recovered partially after receiving 2 L of fluid? Were both the dehydration and the kidney failure likely to have been caused by something else, and if so, would that "something else" be likely to be one of the individual susceptibilities he mentions on p. 336? What is the state of the research on whether or not there is a causal connection between dehydration and kidney failure in *races* (not walks or general exercise) lasting longer than 24 hours?

    Thanks for such an interesting article and comments.

  34. Andy

    I agree with Aaron's view for the most part. My experience is certainly the same as his (and many others) that regular and sometimes heavy (500-1000mg/hr)sodium intake prevents or alleviates cramping. (No, I haven't run Barkley, just a few 50ks, 50ms, and one 100k, and of course thousands of training hours.) The results in my repeated "N of 1" studies cannot be accounted for by confounding factors like stride, pace, braking, etc.

    Joe, I appreciate and respect the review of research. But as a researcher and PhD myself, it is critical to be sure not to confuse scientific findings with universal truths. Hidden in every study outcome are many individuals who do not conform to the overall pattern — Just because there is a "significant" effect or trend statistically does not mean it is true for all. As Cary above said, we are each an "experiment of one." As a behavioral scientist I am a big believer in the placebo effect, but I am confident that as more sophisticated research is conducted on this topic we will see that there is a real nexus between intake of sodium and other electrolytes and muscle cramping.

    1. OOJ

      Andy-

      Great post, thanks.

      Given the research – and both runners' (and my own) anecdotal findings – there's definitely disagreement. Tons of folks – myself included – take and benefit from supplemental sodium.

      The question, therefore, is WHY?

      It may be demonstrated – quite strongly – that blood sodium concentrations elevate with exercise, and that blood sodium levels are maintained, even in extreme, multi-day deprivation studies.

      The REAL question is, is there another physiological avenue by which sodium enhances performance? Is the in the muscle cell? Nerve cell? Or simply placebo? All of the above?

      There very well may be a benefit from these – or other unknown – avenues…

  35. Josh White

    Alicia-

    I'm a physician, and I can say for certain that hydration status is intimately linked to end-organ injury, including renal failure. To say that there's no causal relationship is just plain wrong. Granted, in instances such as ultramarathons, there are numerous other factors at play that can/will produce renal injury … rhabdo, NSAIDS, electrolyte imbalances, heat injury, etc., etc.

    But, to suggest that low hydration does not cause injury is completely ludicrous. Theoretical experiment … get a pet rat. Stop giving it water. Keep giving it everything else … food, sodium, whatever. See what happens. Eventually, it will die. Why? Because when your hydration status gets low enough, it starts injuring organs, kidneys included. Please note, I am not suggesting you actually do this, and am not an advocate of animal cruelty. It's simply an extreme example to highlight some potentially dangerous thought processes out there.

    One major aspect of the statements made by Noakes that bothers me is that he is arguing from both ends of the spectrum. In one breath, he makes the comment that your body self regulates wonderfully and you don't need to mess with it. You don't need to drink until you're thirsty, don't need sodium, etc., etc. Then, in the next breath, he states that your kidneys don't regulate well because of SIADH and you can't trust your urine color or consistency.

    I think it's crucial for all of us to back up here and recognize two basic biological principles:

    1 – Your body cannot exist and self regulate in isolation. Take the rat in the box example. Don't give it water, and it dies.

    2 – When your body excretes/uses something, it needs to be replaced. When you run, you burn fuel stores (glucose, fat, etc.), utilize water in various forms (sweating, etc.), and excrete sodium in the form of sweat. Now, there is clearly room for debate on how much/what form replacement is necessary. I am not saying that Noake's concepts are wrong. It's very possible to take too much water, too much sodium and hurt yourself. It's happened many, many times. But a lot of what has been said here is over-generalized. It's just as possible to deprive yourself of these things and hurt yourself. Frankly, you could sit in a chair for an extended period, and if you deprived yourself of calories, sodium, and water, eventually you would hurt yourself.

    Final comment. Ultra runners take things to extreme by definition. Thus, when you make generalizations … shoes with cushioning are bad, sugar is bad, salt is bad, fat is bad, water is bad, whatever … somebody is going to take that concept to it's extreme end and hurt themselves. Perfect example are all the metatarsal fractures coming out of the barefoot/minimalist movement. The answer folks, is that, like most everything in life … the truth is in the middle.

    1. OOJ

      Dr White-

      Thanks for your input. I take a bit of an issue with your post, given that:

      1. You begin with an argument based on extremes (e.g NO water)

      2. You end with an argument based on moderation.

      >"…To suggest that low hydration does not cause injury is completely ludicrous. Theoretical experiment … get a pet rat. Stop giving it water. Keep giving it everything else … food, sodium, whatever. See what happens. Eventually, it will die."

      Dr White, where in this review – or in Dr Noakes book – does it recommend complete avoidance of water? Of course, absolute water deprivation will cause injury and death.

      The point is, the frequency and color of urine – in absence of any other symptom, in the presence of regularity of fluid intake (during a race, or in a rat cage) – is insufficient data to determine hydration status.

      >"One major aspect of the statements made by Noakes that bothers me is that he is arguing from both ends of the spectrum. In one breath, he makes the comment that your body self regulates wonderfully and you don’t need to mess with it. You don’t need to drink until you’re thirsty, don’t need sodium, etc., etc. Then, in the next breath, he states that your kidneys don’t regulate well because of SIADH and you can’t trust your urine color or consistency."

      You're correct. 1.) Humans self-regulate wonderfully. 2.) You can't trust urine color or consistency [read: frequency].

      SIADH is simply a condition of holding onto water "inappropriately". SIADH does not cause mal-regulation by the kidney, nor does it cause a problem of self-regulation. It does, however, cause confusion about one data point: urine frequency/color.

      SIADH becomes problematic *only* when we *flatly ignore* the other information from the body: fluid intake history, weight status, swelling, nausea, vomiting, headache, altered mental status.

      As for your points:

      >"1 – Your body cannot exist and self regulate in isolation. Take the rat in the box example. Don’t give it water, and it dies."

      Another argument of extreme. Yes, take any living organism and place it in an extreme environment, and it will eventually die. There is no part of the book or this review that advocates this approach to training, racing, or living.

      >"2 – When your body excretes/uses something, it needs to be replaced. When you run, you burn fuel stores (glucose, fat, etc.), utilize water in various forms (sweating, etc.), and excrete sodium in the form of sweat."

      Far too simplistic. Must an obese person replace all calories? Likewise, it has been proven *with research* that salty sweaters who deposit salts on skin and clothes, do so because of excess internal stores.

      Again, too extreme: yes, of course, ultimately stores of water, fuel and sodium must be replaced but *the research demonstrates* DURING ENDURANCE RACES OF 24 HOURS OR LESS:

      1.) Drinking to thirst only (and, based on research, including 24hr races in extreme heat – 400-800ml/hr) is sufficient and ideal for optimal performance, even if it results in weight loss percentages exceeding 8%.

      2.) Sodium does not need to be replaced to maintain blood sodium concentrations

      3.) Performance is enhanced by 60-100g of glucose per hour.

      I encourage you to read the book and do your own review of the literature, namely the studies involving sodium deprivation and endurance exercise. A good start is Table 4.2 on page 129 of Waterlogged, which shows pre- and post-race sodium values of actual race performances (marathon to 10-day race). 29 of 30 studies showed an INCREASE in blood sodium levels in post-race athletes. (The lone outlier is deemed erroneous, as both pre- and post-race levels were low).

      Ultimately, your last point is spot-on: listening to one's own body, and aiming to achieve homeostatic balance will avoid physiological problems. But one must listen to ALL pieces of data:

      – Dark urine + lack of urine + acute weight loses + strong thirst + history of not drinking all day == dehydration.

      – Dark urine + lack of urine + lack of weight loss (and/or weight gain) + lack of thirst + history of regular drinking =/= dehydration.

      1. Josh White

        OOJ-

        You're correct, my examples were extreme and simplistic, but that was simply to illustrate a point. Again, in general, I'm not saying that the concepts in the book are incorrect, although I do take issue with a couple of statements. I still stand behind my statement that enough dehydration will result in renal injury … drop your total water body & plasma volume enough and it becomes physiologically impossible not to incur injury. And yes, in general, I agree that the body self-regulates wonderfully. But SIADH is a failure of that. The "I" stands for inappropriate. The comment you make about a single data point is very good form (and science), but my point is simply that the body does not tell the truth 100% of the time.

        The finer details of all the physiology are probably irrelevant to this discussion, and I'll readily admit I haven't done an exhaustive literature search.

        My real concern is dogma, which the book is fighting against. But I worry that it could set off a new dogma in the other direction. It's not difficult at all for me to imagine a near future where runners warn each other and themselves not to drink too much. After all, these are folks that do things like Hardrock and Badwater … ultra runners are entertained and psychologically driven to take things to extreme. Perhaps my concerns are unwarranted … I don't know. But I think the likelihood of many people out there misinterpreting what Noakes is saying is relatively high. I worry that many won't read the details in the book, many will simply pick up bits and pieces from friends, some will become afraid of EAH and actively avoid water, and some will simply not understand the science.

        So perhaps the better question is, how do we take the learnings from this book and prevent people from swinging too far in the other direction?

  36. OOJ

    Alicia-

    To address your question on the two footnotes:

    Footnote #1:

    "“She chose to drink very little during the race in which she lost 5kg or 11% of her starting body weight. She did not pass any urine for some hours after the race and showed evidence of transient acute renal failure that recovered partially after she had received 2 L of fluid intravenously. Evidence for continuous mild renal dysfunction was present for the 14 days after the race at which she was studied.”"

    This note was in relation to the point *this point*:

    Thirst mechanism + readily available water + listening to thirst mechanism = drink water = "avoid life-threatening dehydration" at its possible effects on all physiological systems.

    The footnote mentioned a single runner who chose to "drink very little" over the course of an 89K (57mi) race. She happened to experience "transient acute kidney failure" and "mild renal dysfunction" for two weeks after.

    To recap:

    – This is one single data point of a runner who chose to ignore their thirst mechanism and drink "very little" for a 56 mile race.

    – DESPITE completely ignoring thirst, this runner had "transient" and reversible kidney dysfunction.

    – The main point is, those who LISTEN to thirst mechanism (to drink or not to drink) will avoid harm;

    – Those who ignore it are prone to harm (though in this single case study, that harm was temporary and reversible)

    Footnote #2:

    Noakes was criticizing the 2007 ACSM report, which implied a connection between dehydration and rhabo. His points were:

    1.) There may be a correlation between kidney failure and rhabdo, and/or dehydration.

    2.) However, there is NO evidence to suggest a "causal" relationship (e.g. A -> B) to be found in research.

    3.) Conditions such has heatstroke, rhabo, and kidney failure are SO RARE that there have not been enough documented, researched cases to substantiate ANY relationship between these conditions and issues of hydration (too much vs not enough), electrolyes (too much vs not enough) or other environmental factors.

    It *should* be noted, however, that weak (lacking enough documented cases) associations have been established linking:

    1.) kidney failure to NSAID use

    2.) heat stroke to physiological pathology (e.g. viral infections, disease) and (separately) drug use (amphetamines, diet supplements, etc).

    But even these associations are only correlates, not causes.

    To address your questions:

    >Could Dr. Noakes clarify, then, whether he meant to imply in the note on p. 45 that the runner’s dehydration had any causal connection to her transient kidney failure?

    He did not imply causal connection. He simply pointed out a single case study of a runner that drank "very little" for 56 miles.

    >If not, what is the reason for mentioning that she recovered partially after receiving 2 L of fluid?

    Because she was dehydrated; she "drank very little"!

    >Were both the dehydration and the kidney failure likely to have been caused by something else, and if so, would that “something else” be likely to be one of the individual susceptibilities he mentions on p. 336?

    It's possible. Given the degree of pharmaceutical use in running (ranging from NSAID use to banned substances – recently found in the 2012 Comrades male winner), it IS possible an outside factor caused or facilitated her kidney dsyfunction. There's no way of knowing. Again, only a single data point.

    She also could've been sick. Again, insufficient data. His point was to mention what happened to a single runner in the most "extreme" case of lack of fluid intake ever documented in an ultramarathon.

    >What is the state of the research on whether or not there is a causal connection between dehydration and kidney failure in *races* (not walks or general exercise) lasting longer than 24 hours?

    The research findings are, unfortunately, quite varied. Marty Hoffman et al recently published a study from the 2009 WS – a case study of five runners with severe hyponatremia with rhabo and/or kidney failure. Of the five severely hyponatremic runners:

    – Those with kidney failure showed a 1.3% (+/- 3.8) weight LOSS.

    – Those without kidney failure had a 2.5% (+/- 3.5) weight GAIN.

    While that difference might be significant, consider that the average weight loss across all 24 hour/100 mile races is in that very same loss/gain range. So the research to date – looking at a *single value of data* – is very weak.

    To conclude one of Noakes' three main themes of the book:

    1.) Ultimately we can only trust the science and data at hand; associations and correlations are that alone – NOT causations or "fact", unless fully proven.

    2.) Relying on a single data value is insufficent to make an accurate diagnosis.

    3.) If you listen to your body you will avoid physiological problems.

  37. Kyra

    I get heat exhaustion very easily, on marathon runs, not 5Ks. So, yes, I do take lots of salt in order to be able to take lots of water. If this is wrong, what are my other options for dealing with the heat? I was able to buy a popsicle from a street vendor during my marathon today, but this is the first time I have had that option. Any other advice for dealing with heat without over-watering?

    1. OOJ

      Kyra-

      Thanks for the question. Dr Noakes writes about the concept of heat exhaustion. He states on page 347:

      "Heat exhaustion is a misnomer for a number of reasons. It is use purely to describe the circumstances (heat) in which a person chooses to stop exercising. This is then labeled as exhaustion even though the athlete may have no symptoms or other evidence of illness."

      That said, heat represents a physical and psychological barrier to performance – no different than hills, bad terrain, extremes of precipitation.

      Possible solutions to tackling distance running in the heat include:

      – Heat acclimatization: training in "race day heat" conditions for at least 5 days, for >1hr

      – External cooling measures (e.g. "dousing"): staying wet or cool using water over the head, or ice in a hat, hankerchief or or means on the body.

      From my personal experience, "dousing" provides incredible benefit. Even if there's only fleeting physical relief (likely only a temporary "dip" in overall body temp), then psychological relief and refreshment is intense and long-lasting.

  38. Dale

    Interesting. I ran the West Highland Way (Scotland) in freezing storm conditions late last Novemeber and for the latter half I was urinating on average 6 times per hour. Clearly disturbed by my lack of progress due to this I posted on an international ultra running forum for answers to the problem.

    A well known rep repled telling me that my problem was a lack of electrolytes i.e. salts.

    I've never been able to understand this and my gut feeling tells me he was wrong. Nevertheless, I'm still in the dark????? What studies are out there to help me with this dilemma? Is it related to salt or not? What is the term for what happened? And more importantly, how do I stop it from happening again?

  39. OOJ

    Dale-

    Thanks for the comment.

    Dispensing health advice "on the fly" is always dicey, because one never knows the "whole story". Moreover, we tend to gravitate toward "typical". But with every individual, there is no typical.

    The "typical" explanation of peeing a lot in ultras is, "Oh, you drank too much", or, "You didn't have enough salt.". But you have insufficent info to make either judgment.

    Here are the only things you said:

    1.) You peed 6x/hr. Therefore, you had polyuria.

    2.) You ran in freezing storm conditions.

    It's POSSIBLE (though unknown) that you simply had cold diuresis. Simply put, in very cold conditions, the body will decrease overall blood plasma volume in order to preserve heat. So you pee a lot.

    Here's the best explanation I could find, courtesy of Google:

    http://www.globalbioweather.com/weather_cold_diur

    1. Dale

      Thanks OOJ.

      Yep, point taken re the variables not told. I think the cold diuress may have something to do with it; what I failed to mention was that I was being accompanied by a good friend who was suffering due to a recent chest infection.

      Consequently we slowed after the half way point and walked for huge portions of the challenge as he worsened. Obviously the slow pace combined with the cold weather and perhaps prompted me to urinate an awful lot.

      Around the half way marker I started drinking coffee too and had been omitting caffeine from my diet for the previous 2-3weeks.

      Perhaps there had been a combination of the two factors. I certainly don't believe I had been drinking too much water, nor do I think it had anything to do with electrolytes. But these are just gut feelings.

      Thanks again, without your input I would still be wondering. Thing is, I'm still kinda wondering; my friend wasn't suffering with the same problem, though he did have other things to deal with!

  40. Alicia

    Thanks, both of you, for the replies. OOJ–my question of "what is the reason for mentioning that she recovered partially after receiving 2 L of fluid?" maybe wasn't clear but I was talking about *kidney* recovery, which is the type of recovery Noakes talks about in that footnote, not recovery from dehydration. Again, I realize saying that more fluid led to kidney recovery doesn't actually mean he thinks dehydration caused her kidney problems, but it certainly could imply that he thinks that.

  41. Korey

    So this weekend I didn't have any electrolytes in the first 20 miles of my 50K.

    You know what happened? I cramped up for my first time!

    Whether it's the placebo effect or not, I'm taking S!Caps forever.

  42. larry gassan

    Interesting, but lets look at the larger matrix of American exercise culture. What effect overall changes in diet [additives, hormones, etc], technology [ie air-conditioning, fabrics], have had? Furthermore, what is unknown or lost from the historical record is how non-Europeans dealt with heat and hydration. If lacrosse is any guide, they didn't stagger out on a field with 20lbs of body armor either.

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