It sounds like a dieter’s dream: burn calories while you sleep. No special foods, no exercise, just restful sleep and calories are burned. But is this even true? And if so, how many calories do you burn sleeping?
The simple answer is yes, our bodies do burn calories while we sleep. The average adult, sleep science says, burns approximately 50 calories an hour while sleeping. While we may be unaware of doing anything at all, our bodies are quite busy, and they need energy to complete the tasks nature has assigned them, which means burning calories.
Is it enough to lose weight without any real effort on our parts? How long would you need to sleep to burn a significant number of calories and achieve weight loss? These, and other related issues, are what we are going to take a closer look at here.
While, to us, it seems that while we are sleeping, we are simply doing just that, we actually sleep in cycles, each of which has a distinct and important purpose.
Sleep can be divided into two types: REM and non REM sleep. REM stands for rapid eye movement, and that is indeed occurring when people enter this stage of sleep, but a lot more is going on when you sleep, as this is the time your body gets to work repairing the damage of the day, and works on things like muscle building, brain cell repair and more.
One of the big reasons that we feel so awful when we do not get enough sleep is that we are denying our bodies the chance to repair and renew itself, which it does surprisingly efficiently when allowed the optimal amount of rest. The seemingly tired advice ‘you’ll feel better after a good night’s sleep’ is actually rather wise after all!
Our bodies cycle through three stages of NREM sleep, and one cycle of REM sleep every 90-110 minutes or so. In stage 3 of NREM sleep, when you are much harder to wake, and if you are woken you are likely to feel groggy and disoriented, the body does the majority of its work, and burns the most calories.
Therefore, one of the reasons the number of calories a person burns while sleeping varies according to how many times their body enters, and leaves, this stage of sleep.
The number of calories burned while sleeping also varies based on weight and age.
The heavier you are, the more calories you will burn while sleeping. For example, a person who weighs 125lbs will burn approximately 38 calories an hour for a total of 304 calories if they get the recommended eight hours, while a person who weighs 150 lbs might burn 46 calories, or around 368 calories.
In theory, the heavier you are, the more calories a good night’s sleep will burn, making sleep a good way to lose weight. However, that is not quite the case. During sleep, people do lose weight. However, water loss via breathing and sweating accounts for the majority of this. The calories burned are not considered active calories, and those are the ones that burn fat.
So, if you think that you can skip the gym, and enjoy an extra ice cream instead, and still stay on track with your weight loss or weight maintenance goals, sadly, that is not the case.
Sleep is important to maintaining a healthy weight, though, and it does support your other weight maintenance efforts and make them more effective.
Researchers have also linked hedonic eating to shorter sleeping intervals. When a person eats hedonically, they eat for no more than the sheer pleasure of it. This practice may lead to more poor food choices and a larger calorie intake over time.
Individuals who sleep for longer periods of time, on the other hand, are less prone to eat hedonically and want non-nutritious pleasure foods.
In addition, a study from 2021 found that when university students had higher sleep quality, their hedonic hunger dropped. This shows that following a good night’s sleep, people consume fewer calories and make more healthful food choices since they don’t feel compelled to eat for pleasure.
It’s worth noting that all of these studies mention sleep quality as often as they do sleep duration. If your sleep is fitful and disturbed, you will enter non REM sleep less often and therefore your body won’t go through all the work it is supposed to.
These days, the notion that everyone needs eight hours of sleep is being challenged, to a certain extent at least. And as sleep science is taken more seriously – which it was not for many years – it has also become more apparent that some people can function well on far less sleep than others.
However, some basic guidelines still exist. According to the National Sleep Foundation, the American Academy of Sleep Medicine and the CDC, the following are helpful guidelines for the amount of optimal sleep a person should get at each stage of their life to reap the biggest benefit from it.
- Newborn (0–3 months): 14–17 hours (National Sleep Foundation)
- Infant (4–12 months): 12–16 hours per 24 hours (including naps)
- Toddler (1–2 years): 11–14 hours per 24 hours (including naps)
- Preschool (3–5 years):10–13 hours per 24 hours (including naps)
- Children (6–12 years): 9–12 hours per 24 hours
- Teens (13–18 years): 8–10 hours per 24 hours
- Adults (18–60 years): 7-8 hours per night
- 61–64 years: 7–9 hours per night
- 65 years +: 7–8 hours per night
These guidelines refer to restorative sleep, though, which cycles through the four stages of sleep several times. All of this means that the quality of the sleep you get is every bit as important as the actual quantity.
If better sleep results in better health (and more calories burned) you’ll want to know how you can try to improve yours, especially if you sleep poorly now. There is no magic bullet here, but there are some basics you can ensure you keep in mind.
What you do before you go to bed can have a significant impact on the quality of your sleep. Here are some of the things sleep experts suggest you do to help ensure you get the deep, restful sleep your mind and body needs (and maybe burn a few more calories as well!)
Try to eat your last meal of the day at least four hours before bed. If you feel you must have a late night snack, make it something light and healthy.
Ensure your bedroom is at the right temperature for optimum sleep. This should be what is jokingly termed as “Goldilocks temperature” by sleep scientists, not too hot and not too cold. 60 to 67° F (15 to 19° C) is ideal. There is an added bonus here too, as by turning down the thermostat on your heat, or up on your air conditioner at night you’ll save money too!
Keep your room as dark as possible. A small nightlight (if you need it) is as much light as you need.
Minimize the exposure to electronics you have right before bed. A TV in the bedroom is never conducive to sleep, but it is your smartphone that is more of a problem. Not only can it prevent your mind from relaxing in the way it needs to before bed, but some studies also suggest that the blue light emitted by cellphones and tablets minimize the production of melatonin, something your body naturally produces to help you sleep.
Sleep tracking is popular these days, and you may be wondering if you can track the calories you burn in your sleep. The answer here is no, as they are not active calories, which are the kind a tracker like the Apple Watch can monitor.
What the Apple Watch can do is monitor certain aspects of your sleep to determine its quality if you wear it while asleep. If you are not an Apple fan, most other smartwatches can do a similar thing.
If you don’t want to wear a smartwatch to bed, but do want to monitor your sleep, a sleep ring like the Go2Sleep Tracker or the Amazon Halo bracelet band are alternatives that can offer even more data to help you determine the quality of your sleep. You can even track your sleep without wearing a gadget at all, by making use of an under mattress sleep tracker like the Withings Sleep tracking mat.