Exercising and performing at altitude is difficult. In fact, it sucks. Being a sea-level dweller who just competed in a Spartan race above 6000 feet, the effects were more than a myth even at a low altitude.

In this article, we’ll discuss some of the effects of elevation on human performance as well as some tips to mitigate them.

Performing physical activity at relatively high altitude for a prolonged period of time will significantly degrade your physical performance (I know, shocker), according to the Army Public Health Center. Determining what exactly qualifies as “high elevation” is another story but many elite athletes consider 5000ft to be the mark.

It can be subjective as to where exactly you will start feeling effects, but the Army found altitude sickness and illness become more common and greater starting around the 2400-4000m (7,800-13,000ft) range. Above the 18,000 feet range, the human body struggles to survive much less thrive physically.

While we do know aerobic exercise capacity is “reduced by about 10% per 3,300 feet of altitude gain above 4,900 feet,” one would think the higher you go the harder it is to perform (Under Armor Fitness). The same article also mentions it is reduced even further by “30% at 14,700 feet compared to sea-level performance.” Some people respond well to the change but others do not. Either way, human performance is reduced in some capacity at relatively high altitude.

How much will the altitude affect you? Well, it depends. Some believe this is again totally subjective while others think it can be predicted based on your home sea-level. It appears to be a factor in your hydration, nutrition, acclimatization, and conditioning on the day of the event. Hydration is particularly key because the body’s ability to sense deficiencies is reduced substantially. This means while the elevation is expediting your dehydration, it will also reduce the thirst reflex which further contributes to more dehydration.

Speaking of reflexes–and interestingly enough–your senses are also affected by altitude. The most significantly affected sense in the human body is the vision. According to the APHC, dark adaptation is “significantly reduced” at altitudes as low as 2,438 meters (8000 feet).

The Good News

Despite the fact you are literally dying the moment you start climbing elevation, there are some significant benefits to training and performing at a higher elevation. There is a good reason why the U.S. Olympic Training Center is in Colorado Springs, CO (1900m) and the internationally renowned Wales rugby team trains in Switzerland.

The human body is an incredible machine. It can and will adapt rather quickly to changes in elevation. As we discussed earlier, higher elevation means less oxygen available in the atmosphere. The heart and lungs have to work harder with less to fuel the body. The body adjusts by creating more red blood cells over time to allow your body to more easily supply oxygen to muscles and organs. Whats more, it will even relax the way your red blood cells “grip” the oxygen making delivery more efficient (Lovett). These effects can last for weeks or even months.

So how long does adaptation take? Again, it depends. We do know it takes weeks to produce more red blood cells but none of us have the time to play Hugh Glass in the mountains for weeks before a Spartan Race; although you’d probably fit right in. Some studies suggest there are changes happening as soon as overnight (Lovett). Either way, if you are not living and training at that altitude, your best bet is to ease the stress on your body and do your best to manage the adjustment.

What to Do

So you have a race or a hike coming up at altitude and want to know the best way to prepare. By understanding how altitude affects the human body, you will be better equipped to deal with the changes and potential obstacles. There are, however, some additional tips that will set you up for success, especially if you are traveling often.

Ascend gradually if you can . If this is not possible, plan an extra few days on the front end of your trip to adjust to the altitude. UA Fitness recommends “for every 3,300 feet gained, take a rest day.”

. If this is not possible, plan an extra few days on the front end of your trip to adjust to the altitude. UA Fitness recommends “for every 3,300 feet gained, take a rest day.” Train to effort, not pace. It’s important you push the threshold often to simulate the strain your body will be feeling, especially if you live at sea level.

It’s important you push the threshold often to simulate the strain your body will be feeling, especially if you live at sea level. Train with an elevation trainer in the days leading up to your event.

in the days leading up to your event. Dial in your nutrition. Poor nutrition (yes, that includes alcohol) contributes significantly to illness, injury, and ultimately your morale. Eat healthy, albeit temporarily, to ensure you are performing at optimal condition prior to the event.

Poor nutrition (yes, that includes alcohol) contributes significantly to illness, injury, and ultimately your morale. Eat healthy, albeit temporarily, to ensure you are performing at optimal condition prior to the event. Increase your water intake during and in the days leading up to the event. Hydrate mid-race with a CamelBak or hydration vest , even if you don’t think you need it.

My personal experience favors acclimatization. Being right at or below sea level most of my life, running at 6000ft needs some additional care. Spending a week or more around the same elevation as the race helps tremendously. I’d recommend making a trip out of it and race on the last day or right in the middle. Your lungs will thank you.

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Sources

“How High-Altitude Training Can Benefit Elite Endurance Athletes like Runners and Swimmers | UT Southwestern Medical Center.” UTSouthwestern Medical Center, 21 Nov. 2016, utswmed.org/medblog/high-altitude-training/.

Brock, Julie. “What Effects Do High Altitudes Have on the Body?” LIVESTRONG.COM, Leaf Group, 14 Aug. 2017, www.livestrong.com/article/455572-what-effects-do-high-altitudes-have-on-the-body/.

Lovett, Richard A., et al. “Two Weeks in the Mountains Can Change Your Blood for Months.” Science Magazine | AAAS, American Association for the Advancement of Science, 9 Dec. 2017, www.sciencemag.org/news/2016/10/two-weeks-mountains-can-change-your-blood-months.

“How High Altitude Affects Your Performance | MapMyRun.” Under Armour, 26 Feb. 2018, blog.mapmyrun.com/high-altitude-affects-performance

“Altitude Effects on the Human Body.” Army Physical Fitness – Army Public Health Center, 15 Dec. 2015, phc.amedd.army.mil/topics/discond/ai/Pages/Altitude-Effects-on-the-Human-Body.aspx