Are more calories burned in cold or hot weather?
Common questions about calorie burning begin with the following statements:
How many calories do I burn…?
Do I burn more calories (when/if)…?
Many Americans want to know what factors, beyond body weight, gender, age and exercise, affect the amount of calories you burn or expend daily. You may be familiar with the term Basal Metabolic Rate or BMR, also referred to as Resting Metabolic Rate or RMR. There is a formula for calculating BMR for men and women. A quick trick for estimating your BMR is to simply add a “0” to your body weight (in pounds). The number you come up with is your minimum caloric requirement for sustaining life while you are at rest. This is NOT to be confused with your recommended calorie intake for maintaining weight (which includes a physical activity factor). The sum total of all of the chemical reactions and processes that take place in your body, such as building substances (anabolism) and breaking down substances (catabolism) is known as metabolism. Regardless of what you are doing, even if you are bedridden, sitting or standing, your body still needs energy, in the form of calories, to perform functions such as maintaining its temperature and pumping blood through your circulatory system, etc. Interestingly, external factors, such as temperature extremes, body stress (physical stress, such as occurs after surgery) and other factors can affect the amount of calories you burn (at rest).
Does being cold burn calories?
According to Julia Valentour, M.S., EMT-B, American Heart Association Training Center Coordinator, cold weather, on its own, does not increase caloric expenditure. The exception is if you are shivering. When you are shivering, your body must work harder to maintain what is called ‘thermoregulation’ or achieving an optimal body temperature. While shivering, of course, is not a recommended means for burning calories, it burns quite a few, about 400 calories per hour. This is an estimated average and depends upon other factors, such as the external temperature, how long you are exposed (to the cold weather) and the type of clothing you are wearing. Shivering for an extended period of time also depletes your glycogen stores (stored glucose in the liver) and causes extreme fatigue.
Hot weather is a different story
Your body must work hard to cool itself when exposed to the opposing weather extreme. Most people know that sweating results from your body attempting to cool itself. To do this, your body must use cardiovascular effort to pump blood to your skin to promote sweating. Two research studies, published in the ‘Medicine and Science in Sports and Exercise’ journal have indicated that individuals use more energy (burn more calories) when exercising in warm weather versus exercising at very cold or near freezing temperatures. The results of these two research studies conducted on male cyclists suggest that exercising in moderate to warm temperatures is best for exercise endurance (being able to exercise longer), burning fat and, thus, burning more calories. However, it is important to note that the more fit an individual is (athlete versus recreational exerciser), the more fat he burns performing the same exercise.
- Drummond, K.E. & Brefer, L.M.: Nutrition for Foodservice & Culinary Professionals, 7th ed. John Wiley & Sons, Inc., New York, New York, 2010.
- Galloway SD et al. Effects of ambient temperature on the capacity to perform prolonged cycle exercise in man. Med Sci Sports Exerc. 1997 Sep; 29(9): 1240-9.
- JD Layden et al. Effects of reduced ambient temperature on fat utilization during submaximal exercise. Med Sci Sports Exerc. 2002 May; 34(5): 774-9.
- Clark, Nancy (2004). Winter and Nutrition: Fueling for Cold Weather Exercise