As more people look to hiking and mountain climbing for exercise and adventure, a common question arises: does your body burn more calories at higher altitudes? The thin air found at higher elevations places greater demands on your body, potentially increasing calorie burn. However, the relationship is complex and depends on numerous factors. This article examines how altitude impacts calorie expenditure during exercise and daily living. Quick answers provided upfront indicate that:
– Your body does burn more calories at higher altitudes due to increased metabolism and heart rate. However, the increase is generally modest, especially during exercise.
– Calorie burn at altitude depends on the specific elevation, level of exertion, fitness level, acclimatization time, and individual physiology. Significant variability exists between people.
– Altitude’s effects are most noticeable during rest and lower intensity activities. During intense exercise, your workload tends to limit oxygen availability regardless of altitude.
– While altitude exposure can increase calorie burn slightly, diet and exercise remain more important for weight loss and fitness goals. Other impacts of altitude like dehydration may also counteract or limit metabolic benefits.
How Does Altitude Impact Calorie Burn?
Higher altitudes affect your body in several ways that influence calorie expenditure:
Lower air pressure
Thinner, lower pressure air at altitude contains less oxygen. To obtain needed oxygen, you must breathe faster and deeper. This requires extra effort from respiratory muscles, burning more calories. However, this only accounts for a small portion of increased calorie burn.
Increased heart rate
To circulate more oxygen, your heart beats faster at higher altitudes. A faster heart rate burns more calories. Resting heart rate can be 15-25 beats per minute higher at 5,000-8,000 ft compared to sea level. Heart rate remains elevated during physical activity as well.
Increased metabolism
Lower oxygen levels stimulate your sympathetic nervous system. This triggers your body’s fight-or-flight response, increasing blood pressure, breathing, and metabolic rate. Your metabolism rises to produce more energy utilizes more oxygen.
Impaired exercise efficiency
With less oxygen available, your muscles tire faster during exercise. You have to work harder to maintain the same pace and workload, again burning more calories. However, your maximum exercise capacity is reduced at altitude.
Cold weather exposure
Lower atmospheric pressure reduces insulating effects, making higher altitudes colder. Shivering and producing heat to maintain core body temperature requires extra calorie burn. However, cold exposure explains just a small portion of increased calorie expenditure.
How Many More Calories are Burned at Altitude?
The number of additional calories burned at altitude varies substantially based on several factors:
Elevation
Calorie burn increases progressively between 2,000-4,000 feet before leveling off. Differences become more pronounced every 1,000 feet. Highest elevations near 18,000-20,000 ft can double resting metabolic rate. But such drastic elevations are unrealistic for most people.
Activity level
Effects are most noticeable at rest and during non-intense activities like walking. During intense exercise, your workload tends to limit oxygen delivery regardless of altitude. This minimizes elevation impacts.
Fitness level
Well-conditioned athletes can minimize increases in heart rate and metabolic stress from altitude exposure. Less fit individuals are affected more significantly.
Acclimatization time
Adjusting to high altitude takes time. Calorie burn is higher immediately after reaching altitude but decreases over 1-3 weeks as your body adapts. Acclimatization blunts respiratory, heart rate and metabolic effects.
Individual physiology
Genetic factors, health status and other individual variables cause big differences in calorie burn response at altitude. Some people are just more metabolically responsive to hypoxic environments.
Diet and hydration
Not eating enough calories or becoming dehydrated at altitude can increase metabolic stress and calorie needs. Consuming extra calories and fluids helps offset demands.
Considering these factors, here are some general estimates for increased calorie burn at higher altitudes:
| Elevation | Activity | Extra Calories Burned Per Day |
|---|---|---|
| 5,000 feet | Resting | 50-100 calories |
| 5,000 feet | Light exercise | 0-50 calories |
| 10,000 feet | Resting | 100-200 calories |
| 10,000 feet | Light exercise | 0-100 calories |
| 15,000+ feet | Resting | 200-400 calories |
| 15,000+ feet | Light exercise | 50-150 calories |
These are rough estimates that can vary substantially. But in general, an extra 100-300 calories per day is reasonable for most situations. Significant weight loss solely from increased calorie burn at altitude is unlikely.
Limitations to Altitude’s Metabolic Effects
While altitude does impact calorie expenditure, some limitations exist:
Workload overrides effects during exercise
Vigorous cardio and strength training relies heavily on anaerobic metabolism, not oxygen availability. Your pace and workload has a bigger impact on calorie burn than altitude. Training harder dominates over altitude exposure.
Dehydration and appetite changes
Lower humidity and fluids losses at altitude can impair digestion and hydration status. This contributes to appetite loss, less food intake, and dysfunctional metabolism. Any boost in resting calorie burn may be offset by reduced calories consumed.
Poor sleep quality
Many people sleep poorly at altitude, fragmenting sleep cycles. Inadequate sleep can disrupt metabolic and endocrine function. Fatigue also reduces motivation for vigorous training. This compromises exercise capacity.
Less actual activity
Trekking at high altitudes often necessitates slower paces and more rest breaks. You may cover less distance and perform less mechanical work each day compared to lower elevations. Total daily movement can decline.
Thermoregulation challenges
Maintaining proper body temperature is harder at altitude. In cold weather, shivering does burn extra calories. But extreme shivering from hypothermia ceases to produce heat, possibly lowering metabolic rate.
Return to normal upon descent
After acclimatizing for weeks at altitude, metabolic effects quickly reverse once descending to lower elevations. Weight loss or fitness gains are lost unless paired with diet and exercise.
So while altitude can raise calorie needs modestly, it does not replace proper training and nutrition strategies for boosting calorie expenditure.
Tips for Optimizing Calorie Burn at Altitude
Here are some tips to take advantage of altitude’s small metabolic boost:
– Allow 1-3 weeks to acclimatize and overcome initial appetite losses before ramping up training. This maximizes metabolic adaptations.
– Stay well hydrated and maintain adequate calorie intake. This prevents deficient metabolism from dehydration and under-eating.
– Sleep low, train high. Live at altitude but descend periodically to low elevations for high intensity training. This maximizes adaptations while allowing hard training.
– Increase workload gradually over time to continue improving fitness. Your body will adapt to given workloads, so incrementally increase training demands.
– Add weight using a pack or vest to increase difficulty without increasing pace. This keeps intensity higher with impaired cardio capacity at altitude.
– Monitor your heart rate to stay in targeted training zones. Heart rate informs effort and calorie burn during exercise.
– Participate in strength training and high intensity intervals. These vigorous activities remain effective for boosting calorie expenditure.
Conclusion
In summary, your body does burn extra calories at higher altitudes primarily by increasing resting metabolism, heart rate, and oxygen demands. However, the differences amount to just 50-300 extra calories daily for most people. Significant weight loss from altitude exposure alone is unlikely. Workload during exercise remains the prime determinant of calorie expenditure rather than altitude. But using strategies like allowing acclimatization time, maintaining hydration and nutrition, and monitoring training load and heart rate can optimize altitude’s small metabolic effects. While altitude impacts calorie burn marginally, structured diet and exercise based on individual fitness goals and needs remains far more important for producing meaningful improvements in calorie expenditure, fitness, and body composition over time.
