How High Altitude Affects Your Performance

Cristina Goyanes
by Cristina Goyanes
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How High Altitude Affects Your Performance

Whether you’re planning a winter ski trip, training to climb a mountain or looking to do a race at elevation, there are a few key things you need to know about how altitude may affect your body and, ultimately, your athletic performance. Rising several thousand feet above sea level in one day can take a toll on your system, especially if you don’t give yourself enough time to properly acclimate to the thinner air up there.


“High-altitude illnesses are the pathological consequences when ascending too rapidly more than 6,500 feet to 8,200 feet,” says Martin Burtscher, MD, PhD, a professor in the Department of Sport Science at the University of Innsbruck, Austria. “Altitude-related illnesses include acute mountain sickness (AMS), which is usually resolved within two to four days. In rare cases, it may progress to life-threatening forms of high-altitude cerebral edema (HACE) and/or high-altitude pulmonary edema (HAPE).”

Less oxygen isn’t the only issue. You may also have to cope with cooler temps, lower humidity, increased ultraviolet radiation and decreased air pressure, which can all wreak havoc on your body. Indicators that your body may be struggling to adjust include headaches, suppressed hunger, fatigue and nausea, which could lead to vomiting, according to the Centers for Disease Control and Prevention. Other signs of altitude sickness include dizziness and insomnia, manifesting after 6–36 hours of exposure to high altitude, says Burtscher, a mountain guide and former president of the Austrian Society for Alpine and High Altitude Medicine.

If you don’t feel better within two days at altitude and the situation starts to worsen (you have trouble breathing at rest, you’ve developed a bothersome cough when you exercise and feel very weak, and/or you have vision problems and feel confused), seek medical help and start your descent immediately. Ask a doctor about Diamox — an acetazolamide that makes the blood more acidic, improving oxygen saturation in the system — which may help ease symptoms of AMS.


It’s hard to predict who may be most susceptible to developing these symptoms. And unfortunately, being fit doesn’t make you immune to altitude’s effects. “You can have two people coming from the same destination, who have similar weight and fitness levels, respond differently to high altitude,” says Terry Chiplin, founder, owner and camp director of Active at Altitude, a Colorado-based facility for endurance athletes. “We’ve had Olympic-level athletes struggle at altitude more than people who have been less physically trained,” he adds.

It’s totally subjective to the individual and their genetic predisposition. It’s also more common than you think: One in four travellers to the Colorado Rockies — where most hiking trails are above 7,800 feet — experience altitude sickness, according to research from the University of California at Berkeley. But one in two people who visit Cusco, Peru, at 11,150 feet experience this condition.


Feeling out of it may be the worst of it, but it’s not the only negative effect of reduced oxygen intake. It can also throw off your game — be it running, biking, cross-country skiing or hiking — even if you have no symptoms. “Aerobic exercise capacity is reduced by about 10% per 3,300 feet of altitude gain above 4,900 feet. [It’s reduced further] by 30% at 14,700 feet compared to sea-level performance,” Burtscher says.

Folks who already live at a moderate elevation (about 6,500 feet or more) or have had repeated experiences spending time at altitude may have a slight advantage at breaking a sweat above treeline, Burtscher says. A major perk for sea-level dwellers, however, is that when they return home after training on higher ground, they may see a boost in their athletic performance.

“We do training camps at altitude, where athletes stay for one week,” Chiplin says. “We’ve had those athletes return home and set PRs at lower elevation. Research would suggest that the body is starting to make adaptations, which will help, but some of the improvements are beyond what science would suggest is physiologically happening in the body. One of the reasons I’ve come up with is that there may be psychological adaptations, too. We get a lot of people who are used to running in the city come hit the trails in the mountains, and it’s just so inspiring. So I’ve thought that there’s a [mental] component that they take back with them. I think that gives them a lift, too.”


A general rule to keep in mind for future sky-high adventures: Ascend gradually. That means you may need to tack on an extra 48 hours to three weeks before the start of your high-altitude adventure to ensure safe acclimatization at a rate of about 1,000 to 1,600 feet per day. For every 3,300 feet gained, take a rest day. Five days prior to your arrival, Chiplin advises to start consuming 5% more carbohydrates (i.e., extra banana or toast) to make up for the fact that your body burns fuel more quickly at altitude. And once you’re at elevation, avoid alcohol — a dehydrating agent — for the first two days to let yourself get used to this new, drier environment.

When you’re ready to start exercising again, ease into it and use your breath as your guide. If you’re a runner training at or close to sea level, “you know how a long run feels in terms of your breathing intensity,” Chiplin says. “When you come to altitude, that’s the same breathing intensity that you want to create here. It means you’ll be slower, but you don’t want to run any harder because if you do, you’re going to potentially put yourself in a situation where you’re in oxygen debt. That can feel like your breathing is restricted.”

Fight the urge to pick up the pace: “If you do run hard, you’re missing the opportunity to maximize the physiological adaptation that takes place in your body,” Chiplin says. You shall be rewarded for your patience in the long run, especially once you return home to sea level where your body will feast on the surplus of good ol’ oxygen.

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About the Author

Cristina Goyanes
Cristina Goyanes
Cristina Goyanes is a NYC-based freelance editor and writer who covers topics including sports and fitness, health and lifestyle, and adventure travel for various national men’s and women’s magazines and websites. When she’s not feverishly typing stories at her desk, she’s exploring the world, from the Arctic to Antarctica and plenty of countries in between. Follow her adventures and more at


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