If you perform the same exact exercise twice, once in Oklahoma and once in Copper Mountain, Colorado, will your body burn the same amount of calories?
Spend time in the mountains and you will quickly notice breathing becomes challenging and your heart rate is higher than normal. Sea level air is more compressed by all of the air above it, which is a lot of weight pushing down. When you compress a gas such as oxygen it becomes dense. As you go up in elevation there is less density meaning less oxygen. Every breath you take draws in less oxygen. In the mountains, our very remarkable bodies can make several adaptations over weeks or months to make the most of the limited available oxygen. Your breathing rate speeds up to compensate, working the diaphragm muscles harder. Your body makes more red blood cells to carry oxygen, and those blood cells become more efficient at delivering the oxygen to your tissues. Simultaneously, your cells’ mitochondria (energy-producing furnaces) multiply to take in as much oxygen as possible. Changes your body goes through to adapt to the higher altitude can lead to a slight increase in basal metabolic rate (BMR), the amount of energy needed to keep your body running smoothly. With time the BMR lowers but does not return to baseline, so metabolism overall remains ‘slightly’ elevated at higher altitudes.
Although it seems we are working harder to perform daily activities and exercise can be difficult, the additional number of calories burned at higher altitudes is not huge. The slight increase in calorie expenditure is due to increased breathing to get more oxygen into the body, whereby the rib cage and other muscles work harder for ventilation.
While there is a slight increase in the metabolic rate from altitude impact, factors that play a bigger role in burning calories are:
- Some people just naturally have a higher metabolic rate.
- Typically, men have a higher % muscle mass than women, which results in men having 10-15% higher metabolism than women.
- Metabolic rate is highest in childhood. After the age of 20, a person’s metabolic rate tends to drop two percent per decade. This decrease in metabolic rate strongly supports why we must stay active throughout our lives to prevent the typical weight gain of 10 pounds per decade.
- Intensity of cardiovascular exercise. Intensity and duration of cardiovascular aerobic exercise increases calories burned.
- Resistance training. Intensity of weight training increases calories burned during and immediately after the exercise. Resistance training also increases % muscle mass, which will support increased calorie burn over all.
The “take away” is that, yes, metabolism increases slightly at higher altitudes resulting in greater caloric expenditure, but this difference is insignificant. Calorie burn is influenced to a more significant degree by the above factors – regardless of your altitude.