Does altitude affect calorie-burning?

Dear Training at 6500, 

It seems like you’re interested in a different kind of runner’s high! Exercising at a high altitude may lead to you burning slightly more calories that may be beneficial to your exercise goals. That said, switching to a high altitude suddenly may make you feel unwell. This may lead to less intense and effective workouts. The number of calories you burn, whether working out or not, is affected by factors in your life other than altitude such as age and genetics. So, before you hurry to a low-cal locale, consider reading on to learn more about altitude and burning calories.  

What happens when you exercise at a high altitude? 

Typically, the higher you go, the thinner the air gets. This means the oxygen in the air is more spread out at higher altitudes. When you take a breath at a high altitude, you breathe in a little less oxygen than you would at a low altitude. 

Breathing in less oxygen can impact your body in ways that some people find beneficial. For instance, studies suggest that exposure to lower-oxygen conditions can slightly raise your resting metabolic rate (RMR). Your RMR is the amount of energy your body uses—the calories you burn—over time. This means that you may burn more calories spending an hour at a high altitude than you would spending that hour at a low altitude. 

Additionally, your body may improve the way it moves oxygen to your muscles in response to the lower oxygen levels in the air. This could lead to your muscles repairing and growing stronger more quickly after a workout. Exercising at a high altitude may also increase your overall endurance, which is your ability to continue exercising and how long you can do so. For example, if you train at a high altitude, you might be able to exercise for longer stretches of time at a low altitude than you were able to before. This is because your body may improve the way you use the oxygen you breathe in so that it’s used efficiently. 

Are there risks to exercising at a high altitude? 

Working out at a high altitude may also lead to unintended consequences. Switching too quickly from a low altitude to a high altitude can cause a condition known as altitude sickness. You can get altitude sickness when your body doesn’t have enough time to adjust to the sudden drop in oxygen levels. Symptoms of altitude sickness can include:

• Headache 
• Nausea and vomiting 
• Loss of appetite 
• Tiredness 
• Difficulty sleeping 

Adapted from Cleveland Clinic 

Does altitude actually cause you to lose more weight? 

Research suggests that the weight loss many people experience at high altitudes is primarily caused by them eating less because of appetite loss or nausea, rather than them burning more calories because of a slightly increased RMR. Therefore, people exercising at high altitudes may lose weight because they feel unwell, instead of due to their exercise being more effective.  

Additionally, exercise at a high altitude can make you feel tired and out of breath more easily. This can lead you to work out for shorter periods of time, which can decrease the intended effects of your exercise. 

What else affects how many calories you burn? 

Many factors other than altitude can affect the amount of energy (in calories) that you burn during a workout. These include:

• Age: Younger people burn a higher number of calories than older people. This is because younger people generally have higher RMRs. 
• Sex assigned at birth: People assigned male at birth (AMAB) usually burn more calories than people assigned female at birth (AFAB). 
• Body size: People who are larger or heavier generally burn more calories than people who are smaller or lighter. 
• Body composition: People with more muscle mass tend to burn more calories than people with less muscle mass. 
• Activity levels: In general, people who do more physical activity burn more calories. When exercise is more intense, it typically leads to more calories being burned than with lighter exercise. 
• Genetics: Genetics can affect RMR to burn either more or fewer calories. Genetics can also impact hunger, body size and composition, and activity, which can affect energy balance—how many calories are taken in and how many are burned. 
• Pregnancy and chest feeding: People who are pregnant or chestfeeding generally burn more calories. 

Adapted from Medical News Today 

All of these are general trends and none of them are set in stone. It’s certainly possible for the factors impacting calorie burning to impact each person differently! 

In general, exercising is beneficial for your health—no matter the altitude. When you’re working toward specific exercise goals, the amount and intensity of the exercise will be more impactful than the altitude you work out at. If you intend to start training at a high altitude or simply want to learn more about calories and your body, you may consider consulting a health care provider. They may help you better understand how your body specifically burns calories and can help you weigh the risks and possible benefits of exercising at a high altitude. 

Hope this helps you reach your peak performance!