Many people don’t realize that our bodies burn calories all the time, no matter what we’re doing in any given moment. It may seem strange, but our bodies burn calories as we eat, digest food, breathe, and even while we’re sleeping. So, this begs the question, how many calories do you burn sleeping?
In this article, we’re going to explore this question in depth. We’ll be examining all the variables that determine how many calories are burned while sleeping, ways that metabolism affect the amount burned, and much more. Keep reading to learn everything you need to know about how many calories you burn while sleeping.
How Many Calories Do You Burn Sleeping?
Our bodies burn an average of 50 calories per hour while sleeping. This amount may vary based on several factors, one of the largest of which is individual metabolism. The amount may vary widely between different people, but most people will burn around 50 calories an hour during sleep.
The main determining factor is your personal basal metabolic rate (BMR), which refers to the energy needed to carry out basic biological functions like breathing, circulating blood, regulating body temperature, and cellular repair and growth. For most people, your basal metabolic functions will account for around 80% of the calories you burn throughout any given day.
One of the largest calorie burners while asleep is the brain, which burns glucose for energy, and it can consume up to 20% of the calories burnt while sleeping. Additionally, while we sleep our bodies are working to repair and regenerate. This process also takes a lot of energy, especially if you’re healing from an injury or illness. Repair and regeneration can often consume the most calories out of any other factor other than basal metabolic functions while sleeping.
It’s also interesting to note that your body will burn around 15% fewer calories from basal metabolic functions while sleeping as opposed to during the day. This is due in part to not having to spend energy on movement, speaking, or other common functions that take up energy throughout the day.
What Affects Your Basal Metabolic Rate?
As we mentioned earlier, basal metabolic rate is not universal. It differs from person to person, and the ways it differs are based on various factors. Below is a list of each of the main factors that affect the basal metabolic rate:
- Fitness: Being more fit will cause your body to burn more calories even while at rest. This is because muscle burns more energy than fat, even when it’s not being used.
- Gender: According to researchers, men have a higher BMR compared to women, due to their physiology.
- Weight and Height: Smaller organisms require less energy to function, which means the taller or heavier you are, the more calories you burn.
- Age: age plays a huge role in your metabolism. Children and adolescents generally have higher metabolisms than older adults.
- Diet: One of the best ways to manage body fat composition is to maintain a healthy diet.
- Quality of Sleep: How much you sleep, and the quality of your sleep will affect your metabolism. The better sleep you get, the faster your metabolism will work.
- Race: Some races have been proven to have higher or lower BMRs.
- Genetics: Metabolic rates can be heavily affected by genetics. Some may be predisposed to higher or lower metabolisms.
- Medical Conditions and Hormones: There are several health conditions that can increase or lower your BMR, including pregnancy, lactation, menopause, hypothyroidism, or hyperthyroidism. If you feel an underlying condition is negatively affecting your metabolism, you should consult a medical professional.
How Many Calories Do You Burn by Sleeping 8 Hours?
The answer to this question will vary based on a number of factors, such as gender and age. For example, a 40 year old male weighing around 200 lbs. will burn an approximate 500 calories during a period of 8 hours of sleep. This number may be different for people of other body types, gender, or age. The range of calories burnt during an 8 hour sleep period can vary between around 400 calories and 550 calories for most adults.
But what if you want to know exactly how many calories you burn as an individual? There are ways to calculate the exact amount of calories you burn while sleeping, which we’ll explain for you now.
Being able to calculate a precise basal metabolic rate requires the use of a calorimeter, which is a device that measures the amount of energy consumed during a period of time. It analyses the oxygen and carbon dioxide being inhaled and exhaled from your body to determine this rate.
To get the most accurate answer, you would need to spend time in a sleep lab, abstaining from any kind of exercise for 24 hours while also fasting for 12 hours. The sleep test will then be done on an 8 hour period of sleep, and the results should be ready to go.
However, due to the involved and potentially expensive nature of this method, there are other ways to determine your BMR. You can get a rough idea of your BMR by using one of several equations. The most commonly used equation for BMR calculation is the Harris Benedict equation, taking weight, height, age, and gender as variables for the equation.
For men, the equation is: BMR = 66.5 + (13.8 x weight in kg) + (5 x height in cm) – (6.8 x age in years).
For women, the equation is: BMR = 65.5 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in years).
This will give you your BMR for a 24 hour period of time. To get your specific BMR while sleeping for 8 hours, simply divide the result by 24 to get the hourly rate, then multiply by 0.85 to account for the lower metabolic rate while sleeping.
How Many Calories Do You Naturally Burn in a Day?
The answer to this question will vary based on a number of factors, such as gender and age. For example, the average adult male will burn an approximate 2,000 to 3,000 calories naturally during the day. This number may be different for people of other body types, gender, or age. The average adult woman will burn roughly 1,600 to 2,400 calories per day. The range of calories burnt during the day can vary between around 1,500 calories and 3,000 calories for most average adults.
Again, there are a number of factors that contribute to this consumption of calories. Our bodies will burn calories even if we are sedentary, as it takes energy to perform basic bodily functions like digestion, breathing, blood circulation, thinking, and keeping our bodies upright. The various factors we mentioned earlier, like age, weight, gender, and fitness, will determine how many calories you burn during the day.
How Many Calories Do You Burn Sleeping for 4 Hours?
The number of calories you burn during a 4 hour period of sleep will be roughly half of what you would have burned during an 8 hour period of sleep. So, for an average adult male who would have burned anywhere from 400 to 500 calories while sleeping for 8 hours, he would most likely have burned around 200 to 250 calories during a 4 hour period.
Despite this average number of calories burned while sleeping, our bodies will inevitably burn more calories during some stages of sleep. The most intensive calorie burning stage of sleep is the rapid eye movement (REM) cycle of sleep. During this stage, our brains start to exhibit the same level of activity that is seen during the day. Our heart rate also increases, which means your body burns more calories during this stage of sleep.
Depending on how quickly your body naturally falls into its REM cycle, you may burn more calories in a 4 hour span of sleep than others. However, you’ll still always burn more calories during 8 hours of sleep than for 4 hours.
Do You Burn More Calories When You Sleep?
The fact is that you typically will burn more calories during the day, unless you were to hold perfectly still all day. During the day, we eat, move around, walk, and use energy to keep our bodies upright, even while sitting. Many people may also do more strenuous activities, such as exercise or work in a manual labor type of job. All these things will cause our bodies to burn more calories than we would while sleeping.
While it’s true that our bodies burn more calories during our REM cycles, it still is not as much as while we’re up and moving around during the day. In fact, if we oversleep, this will have a negative effect on our metabolisms. Your BMR will effectively slow down if you make a habit of oversleeping, which is why it’s best to stick to getting a solid 8 hours of sleep each night when possible.
Final Thoughts
There is a plethora of factors that contribute to how quickly our bodies burn calories, all determined by our basal metabolic rate. BMR is determined by gender, age, height, weight, level of fitness and activity, and genetics. Some people are predisposed to having a slower or faster BMR, which means some people will burn calories faster than others.
Additionally, there are things that you can do to help your metabolic rate to speed up. Things like regular exercise and maintaining a healthy diet can help you to burn more calories than you would otherwise. Your body will continue to burn calories even while sleeping, and some cycles of sleep will cause you to burn more energy than others. REM cycles are when your body will burn the most calories, as that’s when your brain and heart rate are most active.
Despite being able to burn many calories during sleep, you will almost certainly always burn more calories throughout the day. This is due to the fact that you’re up and about, moving, eating, and engaging your mind in activity throughout the day.
We hope the information we’ve outlined in this article has answered all your questions about how many calories you burn while sleeping. For more interesting facts and information, be sure to check out some of our other articles about sleep.