Most people think calorie burning occurs solely during physical activity. This theory is somewhat correct because the process of burning calories happens while your brain is active, but you can also burn calories when sleeping.
The BMR (basal metabolic rate) describes the energy required by our body to maintain physiological processes like growth, respiration, body temperature control, blood circulation, and cellular repair.
Your body burns calories while performing these functions, which continue throughout our lives, including when we’re sleeping. This piece will focus on how many calories your body burns when you sleep. Read on!
What Is BMR?
The human body constantly needs the energy to function properly and keep warm. Even though your body expends calories during everyday physical activity, up to 80% of total energy is used through basal metabolism.
“Basal metabolism” refers to all bodily functions necessary for maintaining one’s health and survival, such as blood circulation, respiration, cellular development and repair, brain and nerve function, and body temperature control.
All these essential metabolic functions need a steady flow of energy, making it necessary for your body continues to burn calories even while sleeping or in any form of rest mode.
Basal metabolism helps your body to break down calories regularly. The process is measured by your BMR (Basal Metabolic Rate) or RMR Cresting metabolic rate. Essentially, RMR refers to the number of calories a typical person would consume daily if they did nothing but rest.
Your BMR is affected by a wide range of variables, including your age, gender, genetics, and body size.
How to Compute the Amount of Calories You Burn While Sleeping
You must first compute your BMR to ascertain the number of calories your body burns when you are sleeping. However, BMR can be affected by many factors, and computing it can be difficult.
You’ll need specialised equipment to measure how much oxygen you breathe in and out to precisely assess your BMR over a specific time.
The “Harris-Benedict equation” may be used to compute your BMR approximatively. This equation incorporates a person’s height, body mass, age, and gender and has separate formulas for men and women.
The formula is:
- 655.1 + (4.35 x weight) + (4.7 x height) – (4.7 x age) = BMR for women
- 66 + (6.2 x weight) + (12.7 x height) – (6.76 x age) = BMR for men
N/B: where inches represent height and pounds represent weight.
The following formula is used to determine weight and height in kilograms:
- 10 x weight + 6.25 x height – 5 x age – 161 = BMR for women
- 10 x weight + 6.25 x height – 5 x age + 5 = BMR for men
Now that you know how to estimate the number of calories your body burns each day using these calculations, it’s time to figure out the number of calories you will burn while sleeping.
While sleeping, your BMR will decrease by around 15% more than while awake and active because you’re not physically active.
Therefore, you must determine your BMR per hour, multiply it by the number of hours you sleep, and then cut that by 15% to determine how many calories you’ll burn while you sleep.
Simply apply the following calculation to determine how many calories you’ll burn while you sleep:
(BMR / 24) x hours of sleep x 0.85
Remember that these calculations only estimate your BMR and the number of calories you burn when you sleep.
How to Determine the Number of Calories Burnt When You Sleep
The quantity of calories you’ll burn when you sleep isn’t consistent. Numerous internal and environmental variables directly affect how your body burns calories. The influence of a few things on your resting metabolic rate while you sleep is explained in the following list.
1. Sleep Cycle
The REM, or Rapid Eye Movement, and NREM, or Non-Rapid Eye Movement, are the primary sleep phases. You could alternate between the two stages of sleep three to four times a night.
Brain activity significantly reduces during N-REM sleep, causing a slower metabolism. The REM phase follows three levels of the N-REM sleep stage that are more intense than the previous one.
On the other side, your brain is significantly more active during the REM stage, which causes your metabolism to speed up, burning more calories. The quantity of calories burnt is directly impacted by these changes in resting metabolic rate. The REM sleep period burns more calories than N-REM due to increased brain activity.
2. Body Temperature
Your body naturally lowers its temperature to promote sleep. Therefore, keeping your room colder will fasten the start of this process, making it easier for you to fall asleep and help you burn a few calories.
This is because your body will need to burn more calories if it’s chilly to keep warm. The optimal room temperature for a good night’s sleep is between 60 ℉ and 67 ℉ since being too hot or cold can be unpleasant and interrupt your sleep. 
3. Sleep Deprivation
Lack of enough sleep can boost levels of leptin and ghrelin. These hormones encourage weight gain and overeating and can exacerbate preexisting issues — especially if your goal is to lose weight or reduce calories.
Therefore, obtaining little sleep might cause your hunger to appear larger than it is, your fullness indication to be suppressed, and your increased calorie intake.
Additionally, being sleep deprived might make you more likely to make unhealthful decisions. For instance, you could drink more coffee, crave sweets more intensely, and eat more foods high in carbohydrates. These are all signs that your body is attempting to compensate for the lack of sleep.
Lack of sleep can boost your body’s production of cortisol, a hormone that tells your body it should store energy and lead you to retain body fat.
Conversely, sufficient rest each night can aid calorie burning and weight loss. Your body fat won’t accumulate if you get more rest, especially during REM sleep.
4. Late-Night Dinners and Snacks
Mindless eating and not eating meals at the right time often result in weight gain. Therefore, eating properly before bed is a good idea, but eating heavy meals before bed is not.
5. Underlying Medical Conditions
Your resting metabolic rate when you sleep may occasionally be reduced even if you follow a healthy diet and exercise routine. Your metabolism may slow down at this point for various medical reasons, including Cushing syndrome and hypothyroidism. For advice and assessments in this situation, please see your doctor.
6. Muscle Gains
Your body burns more calories the more muscle mass you have. Therefore, strength training in your regular workout will increase the calories you burn while you sleep.
7. Diet
You could improve your ability to sleep better by eating a nutritious diet. Your body’s muscle-to-fat ratio and good eating habits can help you burn more calories.
Bottom Line
Thus, even while you sleep or are resting, your body is still burning calories to maintain several essential bodily processes that we collectively refer to as basal metabolism. The functions that maintain your body healthy, alive, and working, such as breathing, blood circulation, and brain function, are all included in your basal metabolism.
Your body consumes calories daily as a result of your basal metabolism. Your basal metabolic rate relies on various variables, including your body size, genetics, gender, and age. As a result, each person has a unique BMR.
Your BMR may be calculated using a formula that considers your age, height, gender, and body weight. You may also use this BMR value to calculate how many calories you burn each night.
