Fever is your body’s way of fighting infection. To make your body temperature go up, your metabolism goes into overdrive, which requires calories.e60dc2a1-f33c-4a05-9b50-8e3e8e5976293ea305b8-a6f6-4f58-a0f0-c5fb36169de9 While a fever does burn calories and increase metabolism, the exact number of calories burned depends on your basal metabolic rate (BMR) , which is determined by factors like muscle mass and age.e60dc2a1-f33c-4a05-9b50-8e3e8e597629601cdcd9-0916-4974-b752-9a20edc971bf
Fever What Is a Fever? You might think that having a fever is bad, but it’s actually your body’s way of trying to kill invading viruses or bacteria.e60dc2a1-f33c-4a05-9b50-8e3e8e597629e012f694-c0d4-4e0a-b652-2c7a58aa3601 These invaders do not survive as well at higher body temperatures, so your body raises your temperature to fight them. Fever also triggers your immune system to take action.e60dc2a1-f33c-4a05-9b50-8e3e8e597629e012f694-c0d4-4e0a-b652-2c7a58aa3601 The average normal body temperature is about 98.6 degrees F. A fever is present when your body temperature is at 100.4 degrees F or higher.e60dc2a1-f33c-4a05-9b50-8e3e8e5976299e2184e3-c68d-416f-b453-4cac43c6e362 When your body’s defense system detects a foreign invader like a virus, an area of your brain called the hypothalamus is alerted to raise your body temperature, like turning up the thermostat in your home.e60dc2a1-f33c-4a05-9b50-8e3e8e597629b846f853-87a5-4116-a1bd-01fcbdc2044b That increase in the thermostat requires energy from your body’s furnace, called your metabolism, says Oscar Morey Vargas, MD , an endocrinologist at Cleveland Clinic. “Body temperature has an effect on the number of calories burned,” Dr. Vargas says. “Fever, for example, is associated with higher metabolic requirements.” So when you have a fever, your body is working harder.
Metabolism Metabolism and Fever Your metabolism is the process your body uses to make energy from the calories you eat or drink. Oxygen combines with these calories to release energy.e60dc2a1-f33c-4a05-9b50-8e3e8e5976293d902067-1510-44fd-8b49-dbecfadcc79c But your metabolism is unique to you — it’s based on your BMR, which is the energy your body needs to carry out basic functions.e60dc2a1-f33c-4a05-9b50-8e3e8e5976293d902067-1510-44fd-8b49-dbecfadcc79c How many calories that requires depends on many factors, and everybody’s BMR is different. Your BMR is affected by these factors :e60dc2a1-f33c-4a05-9b50-8e3e8e5976293d902067-1510-44fd-8b49-dbecfadcc79c Genes Sex assigned at birth Age Body composition and size Diet Activity level
Calories Burned Calories Burned Differs From Person to Person The bigger your body, the more calories you burn.e60dc2a1-f33c-4a05-9b50-8e3e8e5976299ee2d766-6f5f-4c90-b71d-24d400bde053 People assigned male at birth tend to burn more calories than people assigned female at birth because people people assigned male at birth tend to have more muscle. Similarly, older adults tend to burn fewer calories because they lose muscle over time.e60dc2a1-f33c-4a05-9b50-8e3e8e5976299ee2d766-6f5f-4c90-b71d-24d400bde053 When people have a fever, “they may start shivering for the purpose of rapidly increasing the production of heat by the muscles,” Vargas says. “When this occurs, further increments in energy consumption are expected.”
Nutrition Feed Your Fever Fevers use up calories, and all of those energy needs mean nutrition needs.e60dc2a1-f33c-4a05-9b50-8e3e8e5976291c41af36-7fa2-44fe-9d08-c0d23765d9bb If you have a fever, drink plenty of fluids to avoid dehydration and eat foods that are easy to digest. Try chicken soup for calories and fluid replacement, and to help keep mucus loose and draining.e60dc2a1-f33c-4a05-9b50-8e3e8e59762974341798-b168-4d52-908b-b4f624f98aebe60dc2a1-f33c-4a05-9b50-8e3e8e5976291c41af36-7fa2-44fe-9d08-c0d23765d9bb
The Takeaway A fever burns calories because your metabolism increases to raise your body temperature. How many calories a fever burns depends on your BMR, which varies from person to person. It’s important to stay hydrated and replenish extra calories burned by fever.
Resources We Trust Mayo Clinic Health System: Best Foods to Eat When You Have a Stomach ‘Bug’American Council on Exercise: Resting Metabolic Rate: Best Ways to Measure It — and Raise It, TooCleveland Clinic: Fact or Fiction: Feed a Cold, Starve a Fever?Harvard Health Publishing: Fever in Adults: When to WorryMedlinePlus: Can You Boost Your Metabolism?
How Many Calories Does a Fever Burn?
