Steep and High: Aerobic Training Strategies for Mountains and Altitude

Physiotherapist Joe Uhan’s strategies for aerobic training in the mountains and at altitude.

By on June 8, 2021 | Comments

Stay the CourseFor the first time in my life, I’m living at altitude. My wife and I moved to Steamboat Springs, Colorado (elevation 6,732 feet/2,052 meters) in late May for me to start an advanced physical therapy fellowship training. Prior to the move from where we lived at nearly sea level in Eugene, Oregon, I’d spent limited nights sleeping at high altitude. For anyone who’s also made the shift, you know that it’s an adjustment!

Training and racing in high-altitude mountain environments present a two-pronged challenge to maintaining healthy, balanced running:

  • The altitude and the decreased oxygen (partial pressure) as you get higher in the sky, and
  • The terrain, which tends to be more hilly, rolling, and mountainous.

Successful mountain running–developing fitness while avoiding injury or burnout–often takes a bit more strategy than simple time-based acclimatization. But a little awareness and a few sprinkles of training discipline go a long way!

Mountain Running and Aerobic Deficiency Syndrome

Phil Maffetone first popularized the term Aerobic Deficiency Syndrome (ADS) in his ongoing work to combat the high injury risk, fitness stagnation, and burnout associated with endurance sports by promoting lower-intensity base-building training. ADS is characterized as a training imbalance, where an athlete does too much training volume (as a percentage of work) at medium to high intensity. As expressed in percentage heart rate, this medium/high intensity might be 75- to 90-plus percent, whereas aerobic base-building intensity is usually 60 to 75%. Maffetone promotes his 180 Formula to help individualize aerobic training zones.

Recently, mountain-based training platforms have begun to recognize the challenge of avoiding excessive high-intensity training. Coaching outfits such as Uphill Athlete, led by Steve House and Scott Johnston (authors of both Training for the New Alpinism and Training for the Uphill Athlete), have highlighted the threat of ADS amongst mountain athletes and the easy trap of pushing too intensely on both steep terrain and high altitude. In their work, they often find fit athletes who can push both hard and fast over short distances or durations, but struggle severely over longer (three-plus-hour) efforts in large part because their aerobic system is woefully underdeveloped.

Their philosophy, and that of Maffetone and other like-minded coaches and exercise physiologists, is that endurance athletes–particularly those in ultra-endurance sport–must optimize their physiology to both push fast and hard, at times, as well as go the long haul. This requires both aerobic/fat-burning and anaerobic capacities. And because the anaerobic is so easily triggered on hills, mountains, and at altitude, it takes both attention and discipline to keep in touch with the aerobic.

Strategies for Balanced Aerobic Development

I am learning all this firsthand after my move to altitude, so here I offer four strategies for promoting balanced aerobic development as you move toward hilly, mountainous, and/or high-altitude terrain in your summer adventures.

Have a Metric for Easy

When you’re in the beauty of trails, hills, mountains, and high alpine environments, the joy of the outdoors often distorts perceived effort. The excitement of getting to the top shields the heavy breathing and burn that signals anaerobic efforts. Thus, having some metric for easy effort is important. That can be myriad things, including:

  • Heart rate — A simple heart-rate monitor can provide a good metric for relative effort. And while heart-rate monitoring in training is complicated and controversial, it still matters and remains the best overall metric for understanding physiological strain.
  • Breath quantity and quality — See below.
  • Perceived effort — This is tricky, as most runners (and many coaches) use rate of perceived effort (RPE) as a guideline for exercise. But RPE is highly subjective and swayed by both mood and our surroundings (both interpersonal and environmental). A run with friends in the mountains and while having a lively conversation (at, say a heart rate of 170 beats per minute) may actually feel easier than a solo, boring treadmill run (at 145 beats per minute).
  • All-day pace versus the absence of hard — Because RPE is murky, consider a deeper look at whether or not your base training effort is truly easy.

One of my favorite sayings is, “Easy is not the absence of hard.” Just because it doesn’t truly feel hard, doesn’t mean you are training at an aerobic level. Rather, you may be running medium-hard, but below lactate threshold. By definition, this isn’t aerobic.

Aerobic runs must truly feel easy. Thus, I advise my clients to find their “all-day pace,” an effort that could literally be run all day (e.g. for long ultras such as 100ks and beyond). If they are honest, that all-day pace should be firmly within the parameters of low-stress, fat-burning, aerobic metabolism.

Breath Slowly, Deeply, and Through Your Nose

Breathing may be the most underrated-yet-informative metric available for running effort. Slow, deep breathing is usually only possible during easy efforts. Furthermore, nasal breathing–the ability to both inhale and exhale exclusively through the nose–is a worthy challenge and a novel governor for truly easy efforts.

Breath rate (how frequently), location (nasal, oral, or combination), and depth (how far into the chest cavity we can inhale) are all metrics as well as strategies to enhance aerobic function. Deep, nasal breathing during easy runs promotes a diaphragmatic breath pattern (where we use the diaphragm to fully inflate the lungs). Doing so has benefits, both mechanical and physiological:

  • Optimized trunk posture — In order for breath to truly reach the depths of your lungs, your spinal column must be in neutral. A deep breath will help guide that spinal position. If you are too arched or too flexed, the breath will get caught up in the chest or mid-ribcage.
  • Enhanced core stability — Diaphragmatic breathing engages the diaphragm, which is a crucial core stability muscle that helps maintain stabilizing pressure in the abdomen. An active diaphragm makes a stronger core!
  • Increased air volume — The more air taken in by the lungs equates to increased oxygen uptake by the lung alveoli.
  • Enhanced relaxation — Diaphragmatic breathing has both a mechanical and neurological input, via the vagus nerve, to relax the nervous system, namely the sympathetic (“fight or flight”) system, which drives our “flight” while running. While it doesn’t slow our speed, necessarily, it makes us more relaxed, which impacts energy consumption.
  • Enhanced fat metabolism — Increased oxygen consumption and a down-regulated sympathetic system spares fast-burning glucose and shifts metabolism to fat. Win-win!

Thus, any strategy to promote deeper, more relaxed breathing is going to promote aerobic metabolism, and is only possible through low-intensity activity. My recommendations, in order:

  • Breathe longer/slower — I order my breaths based on steps. For most of my career, an inhale would last only two steps, and an exhale, two steps. Currently, my goal for easy runs is to lengthen that breath-cycle interval to inhale three steps, exhale three steps. It doesn’t seem like much, but this is a 50% increase in breath length. And with that, depth increases and I can feel my diaphragm engage more.
  • Breathe nasally — It can be a formidable challenge to breathe exclusively through the nose. If you are close to sea level, nasal breathing is likely more feasible. The twin passages of the nose are smaller than the throat; thus, when you nasal breathe, try to take longer, slower breaths as well. If nasal breathing seems impossible, try a hybrid approach of inhaling through the nose and exhaling out the mouth or a simultaneous mixture of nasal-plus-oral breathing. While challenging, any enhanced nasal breathing will garner some of the benefits listed above.

Hike Uphill and Run Downhill

Steamboat Springs has a terrific mountain bike and multi-use singletrack system right in town. While exploring, it didn’t take long to discover that even the novice, meandering uphill trails–at altitudes above 8,000 feet–quickly thrust me to the top of the pre-anaerobic gray zone. Then, to my dismay, I’d peak out quickly (and uncomfortably) bomb back down to the bottom.

Thankfully, this trail area features several, more vertical “chutes”–more direct up-and-down access roads. My strategy for balanced aerobic training now involves ascending the steep access roads using a strong (but aerobically easier) uphill hike, then taking my time–and covering more mileage–on the gradual, zig-zag descents. Most of the outing is still running, yet the majority of vertical gain is achieved with lower-intensity powerhiking. Not only is it more aerobically balanced, but such a strategy is also more long trail- and ultramarathon race-specific.

The key to executing vertical-heavy yet still aerobic runs means gaining the vertical with hiking. Runners like to run, and seldom enjoy any walking. But the pathway to increased fitness–and faster and farther running–often means doing some hiking. And skilled powerhiking may be the key to optimal mountain and ultra performance!

Cross Train

Finally, cross training is a terrific option to modulate exercise intensity to remain aerobic.

One barrier to aerobic running, especially at altitude, is the decreased comfort associated with running slower. Many runners have a “groove pace” that is as much biomechanical as it is physiological. Thus, when forced to run easier, the slower pace can feel bad! But chasing that that groove gear, with less oxygen, can exact a toll.

Activity diversification often allows one to exercise at aerobic intensity without the compromising the groove stride. So long as the route is relatively flat, cycling is an excellent option for high-altitude cross training. A simple gear shift can decrease the intensity and cruising speed while maintaining the same cadence and relative pedal resistance.

Other machine options, such as the elliptical, offer the same benefits (though without the enjoyment of dynamic mountain views). Swimming is another option, though experienced swimmers may fall into the same “groove” trap when swimming at higher elevations.

Finally, bonafide hikes offer both the lower-intensity aerobic work and the mountain trail and ultra race specificity. Dedicated hike sessions can really bolster the aerobic system while also supplying key functional strength and mobility benefits that directly apply to running.

Final Thoughts

Hills and mountains offer amazing perspective: they are what draw us outside and up high, perhaps more than anything else in nature. Take advantage of what they offer for fun, adventure, and strength development. But be aware that they exact a heavy cost, for which we must account and prepare! Take a step back, ease off the effort, and recognize that the mountains aren’t going anywhere. They’ll still be there as we amass or own strength to meet their challenges.

Call for Comments

  • Have you found it easy to unintentionally “redline” or “go anaerobic” when you head into the mountains or to high altitude?
  • Do you have any other strategies for keeping your training aerobic on difficult terrain?
Joe Uhan

Joe Uhan is a physical therapist, coach, and ultrarunner in Auburn, California. 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