You may not think of your time spent sleeping as exercise, but the truth is your body is always working no matter what you are doing—and that includes being sprawled out across your bed sleeping. To be clear, the calories you burn while sleeping are minimal— approximately 40 to 55 calories per hour—and there are several factors that come into play with that number, including how much you weigh.
So, while it won’t burn as many calories as you would during a long run, it could burn a couple hundred, if you are sleeping for at least the minimum number of recommended hours, which the CDC says is about seven.
What determines how many calories you burn while sleeping?
Ever heard of resting metabolic rate? It’s the number of calories an individual burns while at rest. According to Alex Rothstein, C.S.C.S., coordinator and instructor for the Exercise Science Program at the New York Institute of Technology, it’s “essentially the minimum energy required for essential physiological functions keeping us alive.”
“When we sleep, we are the most at rest, so our caloric expenditure is based on this,” he says, noting that the elements that influence our caloric expenditure are based on things that affect our metabolism. Those factors include the amount of lean body mass you have, whether you worked out that day, and what type of food you generally eat.
What happens when you don’t get enough sleep?
While you are burning calories during sleep, there are other important ways that sleep affects your calorie intake. When it comes to your calorie needs, both the quality and quantity of your sleep are important.
A constant lack of Zzz’s wreaks havoc on your hunger hormones, increasing the amount of the appetite-stimulating hormone ghrelin and decreasing the amount of the appetite-suppressing hormone leptin in your body.
In other words, you’re prone to eating more when you don’t get enough sleep, according to Men’s Health advisor W. Chris Winter, M.D., a neurologist and sleep specialist, and author of sleep books including The Rested Child. Not only that, but after just one sleepless night, research reveals that you’re also prone to specifically eating more calorie-dense and high-fat foods. (And while there’s nothing wrong with munching on these types of foods in moderation, you may see dips in your running performance if you do so on a regular basis.)
Sleep affects other hormones as well.
“Yes, sleep deprivation—even short term—can result in insulin and glucose imbalances,” says Kuljeet (Kelly) Gill, M.D., a sleep medicine specialist at Northwestern Medicine Central DuPage Hospital. Lack of sleep can also affect how balanced cortisol and your thyroid hormones are.
How does adequate sleep—or lack thereof—affect your workouts?
A good night’s rest is critical to all physiological functions, and not getting the right amount can really be detrimental. When it comes to your workouts, specifically, sleep “influences everything from how you perceive your workout, how tired it is making you, or how focused you are on form, to how much endurance and strength you have,” Rothstein says. “It then influences how well you recover from the workout in order to adapt and come back stronger and more resilient.”
With all the ways a negative night of slumber can affect you, it’s a must to snooze well. To help you get enough sleep, you can try setting a sleep schedule, having a nightly routine— like using the Peloton, Calm, Ten Percent Happier, or Headspace apps to do a quick bedtime meditation—not watching TV in bed, and/or making your room as comfy and cool as possible (you want your room to be about 65 degrees).