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An Introduction to Running at High Altitude

The basics of running at high altitude.

Where the Road Ends A Guide to Trail Running book

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Welcome to this month’s edition of “Where the Road Ends: A Guide to Trail Running,” where we discuss running at high altitude.

“Where the Road Ends” is the name of both this column and the book Meghan Hicks and Bryon Powell of iRunFar published in 2016. The book Where the Road Ends: A Guide to Trail Running is a how-to guide for trail running. We worked with publisher Human Kinetics to develop a book offering the information anyone needs to get started, stay safe, and feel inspired with their trail running. The book Where the Road Ends teaches you how to negotiate technical trails, read a map, build your own training plan, understand the basics of what to drink and eat when you run, and so much more.

This column aims to do the same by publishing sections from the book as well as encouraging conversation in the comments section of each article. We want you to feel inspired and confident as you start trail running as well as connected to iRunFar’s community of off-road runners!

In this article, we excerpt from Chapter 7 to talk about the basics of running at high altitude.

High Altitude and Running Performance

The high mountains have always drawn humans. They are revered by our species, and those who venture into them are celebrated. After we start our way up a mountain, we are called onward by the sirens of the summit.

While our spirits soar as we ascend, the amount of oxygen in the air plummets. The less oxygen that is in the air, the greater the reduction in your cardiovascular performance. In other words, expect to move slower on high-altitude runs and prepare accordingly. Above 5,000 feet (1,500 meters), performance decreases by roughly three percent for every additional 1,000 feet (300 meters) of elevation gained.

However, if you stay at high altitude for several weeks, your body will adapt and some of your sea-level running abilities may return. This is called altitude acclimation, and it happens due to changes in a number of your body’s major systems. One example of this is that your red blood cell count will increase over time at altitude, which allows more oxygen to be delivered to tissues all over your body.

Darcy Piceu - 2017 Hardrock 100

Darcy Piceu running the Hardrock 100, which takes place in Colorado at an average altitude of 11,000 feet (3350 meters). All photos: iRunFar

Altitude-Related Health Issues

Aside from leaving you huffing and puffing, the lower oxygen levels at higher elevations can also make you feel acutely awful. Beginning at around 6,500 feet (2,000 meters), people can begin experiencing acute mountain sickness (AMS). Above that height, the likelihood of developing AMS increases as altitude does. The constellation of unpleasant symptoms of AMS can include a headache, fatigue, nausea, dizziness, and poor sleep. It’s kind of like a mountain hangover. Symptoms can come on within six to 10 hours of arrival at high elevation. They rarely last longer than a couple days. AMS affects people quite differently and can affect the same person quite differently on different occasions.

You can avoid the effects of AMS by not going high, but that’s probably not the answer you’re looking for. The good news is that short outings into the mountains shouldn’t result in AMS. More commonly, AMS becomes an issue when you travel somewhere to run high in the mountains for a few days. In that case, try hydrating better than usual throughout the day, suck down some extra carbohydrate in your meals, and take some over-the-counter remedies to lessen the symptoms should you encounter the effects of AMS.

Even relatively short trips to very high elevations can result in the much more serious, but quite rare, high-altitude pulmonary edema (HAPE). HAPE is fluid in the lungs, and it can occur at an altitude as low as 8,000 feet (2,400 meters) in healthy people. Signs and symptoms of HAPE can include difficulty in breathing at rest, coughing, chest congestion or tightness, wheezing, a blue tinge to the skin, rapid shallow breathing, and a rapid heartbeat. The initial treatment for HAPE is to descend to lower altitude as quickly as possible. After that, a doctor’s visit along with rest, oxygen, and possibly common prescription drugs will get you back to normal.

Much rarer and very serious is high-altitude cerebral edema (HACE), which starts to become an issue above 13,000 feet (4,000 meters) and is nearly exclusive to high-altitude mountaineers who stay at those extreme altitudes for an extended period of time. Therefore, we have little need to delve into it here. Should you be venturing to the high Himalaya or the like, you can learn more the medical emergency that is HACE at the Institute for Altitude Medicine website.

Excerpted from Where the Road Ends: A Guide to Trail Running, by Meghan Hicks and Bryon Powell. Human Kinetics © 2016. 

To learn more, read our in-depth articles about running at high altitude:

Call for Comments

  • Have you experienced acute mountain sickness when you went up to high altitude? What were your symptoms and how long did it last for you?
  • Have you stayed at high altitude for a period of time and observed your body acclimate to feel and run better up there?
Sawatch Mountains scenery

High-altitude mountains.

Meghan Hicks and Bryon Powell
Meghan Hicks and Bryon Powell are respectively iRunFar's Managing Editor and Editor-in-Chief. In 2016, they co-authored the book "Where the Road Ends: A Guide to Trail Running." Learn more about Meghan and Bryon.