When a person goes to sleep, they do not exactly shut down their body, which still needs to burn fat and sugar to perform physiological functions. The human body, therefore, continues to burn calories during periods of sleep. A person’s body type, metabolism, and environment affect the number of calories the body burns while sleeping.

There rate at which the human body burns calories during sleep depends on numerous factors, but researchers nonetheless have calculated an average. On average, the typical human body burns 0.42 calories per pound every hour, which means that heavier people burn more calories during their sleep than smaller people. While it may seem that heavier people burn the most calories per hour during their sleep, there are numerous other variables determining the energy the body uses while it sleeps.

The body type of an individual affects the number of calories he or she expends while sleeping. Muscle requires five times more energy over the course of the day than does fat. A pound of muscle, for example, requires about fifty calories each day whereas a pound of fat only burns about nine calories during that same time. Due to these requirements, more muscular people burn more calories during their sleep than other people.

In addition to a person’s body type, a person’s metabolism determines the number of calories he or she burns during their sleep. Active people burn more calories during their sleep than their more lethargic counterparts. While sleeping, the body replenishes the energy it burned over the course of the previous day, so more active people have to replenish more energy at night, which burns more calories. A person’s activity level, age, sex, and other factors determine their metabolism, and people with higher metabolisms burn more calories during sleep than people with slower metabolisms. For this reason, a person who wants to burn more calories during their sleep should avoid alcohol immediately before bed because alcohol lowers one’s metabolism. In addition to alcohol, the chemical cortisol, which the body produces during periods of stress and restlessness, lowers metabolism, as well. To burn the most calories while sleeping, a person should try to relax as much as possible and achieve a restful sleep. Due to this factor, lack of sleep can lead to weight gain instead of weight loss.

While many corporeal factors determine a person’s calorie-burning rate, the environment has a role, too. During a cold night, the body requires more energy to produce heat and carry out its physiological processes than during a warm night. If a person intends to burn more calories during their sleep, they should try to remain as cool as possible in bed.

Overall, an individual body will burn more or less calories than the average depending on the person’s body type, metabolism, and environment.