How Many Calories Do You Burn When You Sleep?

by Marixie Ann Obsioma, MT, undergrad MD on February 5, 2020

It is practically impossible not to talk about weight loss without the topic of “calories” showing up. For you to lose weight, you must burn more calories than you eat to create a calorie deficit. But, aside from accurately tracking your caloric expenditure and performing exercises, did you know that you can also burn calories while sleeping? 

Though many highly personal factors largely affect the actual amount of calories your body burns daily, you might be surprised to learn that your body is at work using energy even when you are resting. And, there are ways to boost it further! Understanding what calorie is and the many factors involved in calorie burning can help you design effective ways to help you lose weight. Read on to know more. 

What Is A Calorie?

Many people think that calories only have importance with food and weight loss. But actually, a calorie is a unit of heat energy. It is the amount of energy needed to increase a single gram of water by 1°C (1). While it is a measure of how much energy our body needs to function, it can also be useful in various energy-releasing mechanisms outside of the human body. 

Food has calories, but counts may vary. Each food contains a different amount of potential energy. There are three kinds of food that we eat – carbohydrates, proteins, and fats. Carbs and proteins each contain 4 calories per gram, while fats have 9 calories per gram (2). 

Calculating Daily Calorie Burn

We burn calories at rest and through the many activities, we do every day. However, the total amount burned daily will depend on several factors, including your current weight and the type of activities you take. 

One accepted method to determine how many calories you burn daily is the Harris-Benedict Formula. It was formulated in the early 20th century and was revamped twice in 1984 and 1990 for accuracy. This formula is fairly easy to compute. You only have to multiply your basal metabolic rate (BMR) to your average daily activity level. 

BMR, which refers to calorie count an individual burns by simply existing, may vary with genetics, age, size, and sex. Calculate your BMR using pounds for weight, inches for height, and years for age in the following formulas: 

  • For men: 66 + (6.2 x weight) + (12.7 x height) – (6.76 x age)
  • For women: 655.1 + (4.35 x weight) + (4.7 x height) – (4.7 x age)

The results will be used to multiply against your average daily activity, which is graded as follows: 

  • 1.2 points for little to no exercise
  • 1.37 points for light exercises 1–3 days a week
  • 1.55 points for moderate exercises 3–5 days a week
  • 1.725 points for hard exercises 6–7 days a week
  • 1.9 points for a physically demanding job or challenging exercise routines

After calculating the BMR and determining your activity points, you have to multiply the scores to yield the total number of calories you burn daily. 

Other Factors that Affecting Calorie Burning Abilities

As mentioned earlier, a lot of factors can determine how many calories you burn in one day. Some of these factors are uncontrollable, but some can be manipulated. 

These factors include:

  • Age. As you get older, the calories you burn in one day become fewer.
  • Sex. Men, as mentioned previously, burn more calories than women. 
  • Daily Activities. With increased activity, you burn more calories.
  • Body Size. Larger people consume more calories compared to those who are smaller.
  • Body Composition. With increased muscle mass, it is easier to burn more calories.
  • Thermogenesis. This refers to the energy the amount of body used to digest the food.
  • Pregnancy and Breastfeeding. Pregnant women and breastfeeding moms burn more calories compared to non-pregnant women.

Do You Burn Calories When You Are Asleep?

As we have discussed the basics of calculating the average amount of calories you burn daily, sleep or rest doesn’t often come to mind. However, the evidence showed that our brain uses about 20% of our calorie intake daily, and it does this even during sleep (3).  

The exact count of calories you burn during sleep is hard to track though. There is no magic number. It is highly variable based on one’s genetics, daytime activities, and throughout the many sleep stages. That said, there is still a good baseline to determine how many calories you have burned by starting with your BMR (4), which on average is found to be at 45 calories per hour.

BMR is measured after a complete 8 hours of sleep, in the fasted state, and neutral temperature conditions. During sleep, the body works at about 95% of what it does at a simple rest. If you can find your average caloric expenditure at rest, you can calculate nocturnal calories burned using this formula: 


  • (hourly BMR or calories burned) x .95 (same as 95%) x hours slept


The body burns more calories at the stage of deep REM sleep (5) when the brain is very active as it needs more oxygen to function properly. We cycle through many sleep stages, from light to deep and REM, about every 90 minutes and repeat this cycle many times throughout the night. Also, metabolic activity cycles at night. Our brains are just as active during REM sleep, as they are when we are wide awake. 

Can You Increase the Rate of Burning Calories During Sleep?

You can influence all the above-mentioned factors and speed up your rate of burning calories during sleep using the following tactics: 

1. Decrease Your Room Temperature

If you really want to increase the count of calories you burn at night, decrease your room temperature. Aim for at least 60-67 degrees Fahrenheit (6). Exposure to cold temperatures has shown to increase your metabolic rate by promoting brown fat activity (7). Fat stores consist mainly of white fay, but they also include small amounts of brown fat. 

These two types function differently. White fats are mainly for energy storage. However, if present in excessive amounts, it can cause inflammation and insulin resistance. On the other hand, brown fat’s main function is to keep body heat during cold exposure (8, 9). 

Evidence showed that cold exposure could cause browning of white fat (10). Calorie burning is significantly increased in cold temperatures, depending on the amount of active brown fat in the body (11, 12, 13, 14, 15, 16). 

You may also drink cold water more often, take cold showers, and walk outside in cold weather to obtain the benefits of cold exposure. 

2. Get Enough Sleep

You must also be sure to get enough rest and sleep, as deprivation can negatively affect your metabolism. If you only get a few hours of sleep, the calorie-burning is delayed, which causes your metabolism to slow down and you’ll start packing on the pounds. 

Evidence showed that men who slept 5 hours or less a night were 4 times more likely to gain weight (17).  Lack of sleep has also been found to mess with the hormones ghrelin and leptin, which both increases the feelings of hunger (18). 

3. Eat Smaller Meals for Dinner

When you eat large meals close to bedtime, your body will not have enough time and opportunity to metabolize through it. Eating late at night will prompt the brain to produce a growth hormone during stages of deep sleep that will store food as fat instead of fuel. 

4. Avoid Alcohol Before Bedtime

While drinking a few glasses of wine before dinner is fine, limiting your alcohol intake at least 3 hours before bedtime is highly recommended. You have to stop and give yourself some time so that your body can metabolize the alcohol. Otherwise, it will keep you out of those deeper stages of sleep. 

5. Skip the Chocolate

We all love chocolates! In fact, any bar that has at least 70% cacao is among our favorite low-sugar snacks or desserts due to its high concentration of antioxidants and stress-bustling abilities. However, if eaten late in the day, it can cause you trouble sleeping. 

Dark chocolates contain approximately 40-50 mg of caffeine per 40-gram serving. This can greatly prevent your body from snoozing, especially if you are sensitive to the compound. 

6. Invest in Tryp

Eat lamb or turkey if you can! Tryptophan, an amino acid found in several types of meat, has demonstrated powerful sleep-inducing effects. Evidence showed that even just one-fourth gram of skinless chicken drumstick or three ounces of lean turkey meat could help increase hours of sleep significantly, and this can translate into easy weight loss (19). 

7. Schedule A Tea Time

There is something about the ritual of sitting down to a soothing cup of tea that tells our brain to relax and slow down. Certain teas have magical weight loss properties, from dimming your hunger hormones to upping your calorie burn by literally melting fats stored in your cells. Some of the most favorite teas are peppermint, chamomile, lavender, and valerian, which also have sedative properties. 

8. Consume Whole Grains at Lunch

While it is recommended to avoid big meals, alcohol, and coffee before bed, eating complex carbohydrates at lunch is better. Serotonin, which is sourced from whole-grain complex carbohydrates, converts to melatonin in stage 3 REM sleep. Do not take carbs before bedtime. Have them at some point earlier in the day. Approximately 20 grams of insoluble fiber can also help induce good sleep. That’s about 2 pieces of whole-grain sprouted bread or a cup of brown rice. 

9. Try Protein Shakes

Drinking a protein shake before hitting the sack can help boost your metabolism (20). Experts found that men who took an evening snack that included 30 grams of protein had better resting metabolic rate the next day than when eating nothing. Also, protein is more thermogenic than other food groups; thus, it helps your body burns more calories. 

10. Do Yoga and Meditation

Striking some relaxing poses before bed can have a significant influence on sleep quality because of yoga’s focus on breathing and meditation. It can help calm your nervous system, release the tension on muscles, and allows you to block out stress and relax. 

11. Throw Out the Night Lamp

Did you know that exposing yourself to light at night does not only interrupt your chances of good night’s sleep, it can also result in weight gain? One study showed that people who slept in the darkest rooms were 21% less likely to be obese as compared to those who rest in rooms with lights (21). 

12. Hide the Gadgets

Evidence suggests that the more electronics you bring into your bedroom, the fatter you will be, especially the kids. Kids who bask in the glow of a television or an iPad at night don’t get enough rest and sleep, and this leads to poor lifestyle habits. Students with access to a single piece of electronic device were 1.47 times as likely to be overweight as kids with no devices in the bedroom. More so, risk increases with the number of devices being used (22).


If you keep your bedroom conducive for rest and sleep, and you get your recommended 8 hours of sleep daily, you’ll be more likely to burn a few hundred calories even with your eyes closed. But it can still be a fairly small amount, so don’t neglect counting the calories you eat and exercising!



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