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How Many Calories Do You Burn in Your Sleep? (Science-Based)

Connor Sellers
Published by Connor Sellers | Senior Coach
Last updated: August 25, 2023

Setting up a fitness plan for my clients includes diet, exercise, sleep, and supplements that align with their goals.

When I suggest sleeping for at least seven hours a night, every other client asks me how many calories they burn with every extra hour of sleep.

So, I consulted a sleep expert with whom I went over some scientific literature to build upon what I know about fat burning during sleep and what affects it.

Quick Summary

  • An average person burns 40-55 calories during a peaceful sleep.
  • Lean muscle, age, and genetics are some of the factors that influence the number of calories you burn when sleeping.
  • Regular exercise and a healthy diet can boost your metabolism and improve your sleep.

How Many Calories Do You Burn Sleeping?

Top view of a sleeping person

You burn about 40-55 calories per hour while sleeping, according to Harvard Health [1].

But this amount may vary from person to person depending on their basal metabolic rate (BMR) [2].

BMR is the energy used in performing essential functions such as breathing, temperature regulation, circulation, and cell growth and repair.

As you can derive from this definition, the human body uses sleep time to repair and regenerate, besides other normal functions.

And to do this effectively, body temperature drops, and breathing and metabolism slow down.

In case you’re wondering, metabolism is the process where your body converts food to energy so you can get things done.

According to research, a healthy person burns about 15% fewer calories while sleeping than during the day [3]. The same study also suggests that the calorie burn rate is at its minimum in the morning.

Now, to better understand the concept of sleep-time fat burning, we need to examine what may affect BMR during sleep.

What Factors Affect the Basal Metabolic Rate?

A woman stretching in bed

The factors that affect your Basal Metabolic Rate include muscle mass, age, body weight and size, gender, genetics, physical activity, and diet.

Here’s how.

Muscle Mass

Muscle tissues need more energy to function than fat cells.

So the more muscle you have, the more energy you need, which translates to more energy expenditure.

In addition, studies have shown that the more muscle mass you have, the higher the BMR [4].


Basal metabolic rate is known to slow as you get older. This is partly due to the loss of muscle tissue usually experienced in old age [5].

Other factors, such as the changing hormonal and neurological processes associated with age, also account for slowing metabolic rate.

Body Size

Generally, bigger body sizes have a larger BMR than smaller bodies. That's because of large organs and more fluid volume [6].


An old couple sleeping together

Research shows men generally have a higher BMR than women [7]. This is partly because women generally have a slightly higher percentage of body fat and less muscle compared to men.

Additional studies have associated increased body fat in women with a low resting metabolic rate [8].


Your genes can also influence how many calories you burn. You might have inherited a slow BMR from your family or, even worse, a metabolic disorder [9].

Studies show that Chinese and Indians generally have a lower BMR than Europeans. It could be due to dietary differences between the two races [10].

The same differences were seen in studies comparing African Americans to Caucasians, with reports showing the former having a lower RMR than the latter [11].

Physical Activity and Diet

Physical activity and diet also affect how many calories are burned, even when resting. Targeting muscle through exercise grows your muscles and makes them more metabolically active, which enables faster burning of calories.

On the other hand, eating certain meals like high protein foods for muscle gain require more energy to break down, so essentially the amount of energy you expend digesting factors in how many calories you burn at rest, which subsequently affects your body composition.

Health and wellness expert Dr. JB Kirby attributes this to proteins having a high value of Thermic Effect of Food (TEF), which is the energy needed to process the food we eat.

In addition, she also recommends balancing out one’s diet with fruits and vegetables.

How Can You Burn More Calories When Napping?

Side view of a woman sleeping

You can burn more calories while napping by consuming a proper diet, sleeping enough (7-9 hours), and exercising to lose weight regularly.

These activities improve your basal metabolic rate and enable you to burn more calories even while sleeping.

According to new research, an extra hour of sleep each night can help sleep-deprived people eat 270 fewer calories a day [12].

To burn more calories while sleeping, you have to take a keen interest in getting a good night’s sleep of about eight hours.

That's because sleep deprivation can cause a hormone surge that makes you crave high-calorie foods [13].

Sleep Hygiene for Faster Metabolism

One of the healthy ways to optimize your metabolism is to adopt good sleep hygiene habits.

Below are a few suggestions to improve your sleep quality:

  • Maintain a cool, dark, and quiet bedroom environment. Sleeping in a colder room can increase the number of calories burned sleeping.
  • Follow a regular sleep schedule.
  • Avoid eating close to bedtime. And if you must snack, go for a light and healthy snack.
  • Avoid stimulants like coffee when going to sleep. Anything with caffeine keeps you from falling asleep and is the enemy of a good night’s rest.
  • Exercise regularly. It complements a healthy diet and can help regularize your sleeping pattern. Besides, physical activities also assist in weight loss and help increase muscle to boost your metabolism further.

These tips can enable you to get enough deep sleep and maximize the calories burned while in bed.

If you’re wondering whether you need deep sleep to burn more calories, that brings us to our next topic.

Do Sleep Stages Affect Calorie Burning?

A man holding his pillow tight

Yes, sleep stages affect calorie burning, with each stage burning different amounts of calories.

You burn the highest number of calories in the Rapid Eye Movement (REM) stage.

The REM sleep stage is the most energy intensive. It is the stage of sleep where the heart rate is the highest, and the brain has high activity patterns which demand more glucose [14].

Scientists investigating the REM stage found a link between short sleep duration and reduced REM stage [15].

“A lack of REM sleep may have adverse implications for physical and mental health.” - Jayne Leonard, Psychotherapist

Burning calories slows down in the third stage of sleep. In this stage, commonly known as deep sleep, respiration, core body temperature, brain activity, and heart rate are at a minimum [16]. The brain is also at its lowest activity.


Do Night Sweats Burn Calories?

Yes, night sweat is a sign of more calories burned. They indicate increased metabolism. However, they are temporary and are experienced mainly by people who have just started working out or eating healthy diets.

Can Oversleeping Cause Weight Gain?

Yes, oversleeping can cause weight gain. Sleeping excessively is also linked with diabetes, heart ailments, and other conditions beyond weight gain, such as memory loss, depression, and body pains [17].

How Many Hours Should I Sleep to Lose Weight?

To lose weight while you sleep, you should sleep for about 7-9 hours. Try adopting healthy sleeping habits that ensure you sleep the recommended hours. If you still can't clock in enough shut-eye, you may want to visit a physician to check whether you have a sleep disorder.

Get Quality Shut-Eye for Optimal Fat Burning

As experts recommend, at least seven hours of sleep is optimal to support calorie burning at night.

But enough sleep alone may not be sufficient to get you that beach body you want. That's why I always recommend trying out the best night-time fat burner supplement for a little edge.

We’ve extensively tested the products on the list, and all of our test data results confirm their effectiveness in boosting fat burning at night.


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