How many calories do you burn at night?

But when we think about burning calories, we often think of activities like running, swimming or working out at the gym our body never stops completely, not even during sleepin fact, you might be surprised to find that the majority of calories burned by your body actually come from metabolic processes outside of your voluntary control… well, simple survive it is actually an activity that requires energy, a lot of energy, which is used to maintain vital functions such as breathing, blood circulation, body temperature regulation and organ functioning.

This energy consumption, the so-called basal metabolismit represents the most important item of calories you burn every day, except for professional athletes and a few other similar cases.

Even while we sleep, our bodies continue to work to support these essential functions, consuming significant amounts of calories in the process.

Just woken up woman, smiling, turning off alarm clock

Shutterstock/Antonio Guillem

Basal metabolism is the minimum amount of energy (measured in calories) that the body needs to perform its vital functions at rest, such as breathing, maintaining body temperature and organ function. Even during sleep, our body continues to perform these vital functions and therefore continues to burn calories.

How many calories do you burn at night?

For simplicity, the amount of calories burned during sleep can be evaluated without taking into account the thermogenesis induced by dinner, which is a very complicated way of indicating digestion… In the following approximations, we will pretend that we went to bed on an empty stomach, but in reality it also requires calories.

The main factors to consider for a rough estimate are basically 3:

For simplicity, we omit factors with a less relevant impact, although not completely negligible, such as body composition (muscle/fat), sleep quality (poor sleep can affect basal metabolism), environmental temperature, …

The American Sleep Foundation suggests using the Harris-Benedict equation to estimate your daily basal metabolic rate

  • Men: 66.5 + (13.8 x weight in kg) + (5 x height in cm) – (6.8 x age in years)
  • Women: 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in years)

The value you find corresponds to your daily basal metabolic rate, the amount your body uses to keep you alive for 24 hours (you can use one of the many online calculators like this one to easily calculate it). For example, a 50-year-old man, 170 cm tall and weighing 70 kg, has a daily consumption of approximately 1500 kcal per 24 hours. At this point, to calculate approximately how many calories you burn per hour of sleep, divide 24 by the number you found earlier to find your hourly consumption, then multiply by 0.85 (to account for the slowed metabolism during sleep).

For the same subject as before, if he slept for 7 hours, he would burn (approximate results):

  • 1500 / 24 = 62.5 kcal/hour
  • 62.5 * 7 hours of sleep = 440 kcal during the night.

In other words, A 50-year-old man, 170 cm tall and weighing 70 kg, burns approximately 440 kcal during sleep.

For comparison, a 50-year-old woman, 160 cm tall and weighing 60 kg, will burn approximately:

  • Basal metabolism calculated using the Harris-Benedict equation: approximately 1300 kcal
  • 1300 / 24 = 54 kcal/hour
  • 54 * 7 hours of sleep = 380 kcal during the night

A 50-year-old woman, 160 cm tall and weighing 60 kg, burns approximately 380 kcal while sleeping.

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