Burning calories in the bedroom isn’t usually synonymous with sleeping – but that doesn’t mean it can’t be.
Studies have shown that the brain uses 20% of calorie intake per day, even during sleep.
Burning calories in our sleep is necessary because sleep is not a passive activity. How many calories are burned during sleep is highly variable throughout the sleep stages, and based on the person’s daytime activities and genetics.
Essentially, it comes down to a simple formula (yikes, math!):
You start with the number of calories your body burns at rest (called basal metabolic rate). BMR varies depending on mass, height, and age (you can determine yours with this calculator), but on average, this has been found to be about 45 calories per hour.
During sleep, your body functions at about 95% of what it does at simple rest. So, if you can find an average caloric expenditure for an individual at rest (e.g. 45 calories/hour), you can calculate nocturnal calories burned by this equation:
(hourly BMR or calories burned) x .95 (same as 95%) x hours slept
So, 45 x .95 x 8 = 342 during 8 hours of sleep. 45 x 8 = 360 calories burned during 8 hours of rest...5% more than when one is asleep.
With that said, your body burns the most calories during deep REM sleep, when your brain is most active because it requires the most oxygen to function.
If you're interested in maximizing the number of calories you burn during sleep, turn the room temperature down –aim between 60 and 67 degrees Fahrenheit. Sleeping in a colder room forces the body to burn more calories to keep you warm.
So – if you keep your bedroom cool and dark, and you get your recommended 7-9 hours of sleep per night, you'll be more likely to burn a few hundred calories while you sleep.
That’s it. Cancel the gym membership, sleep is your new workout.