Have you ever wondered how many calories you burn while sleeping? While you may think the answer would be “not many,” you might be surprised to learn that your body is at work using energy even when you’re at rest. How many calories you burn has to do with various factors, including your weight, your metabolism, and how much sleep you get each night.

Determining how many calories you burn A person who weighs 125 pounds burns approximately 38 calories per hour sleeping. That doesn’t necessarily sound like a lot. But multiply that by the recommended seven to nine hours of sleep experts say you should get each night, and that’s a total potential of 266 to 342 calories for snoozing. The amount of calories burned increases according to body weight. So, a person who weighs 150 pounds might burn 46 calories an hour or between 322 and 414 calories a night. And a person who weighs 185 pounds might burn around 56 calories or between 392 and 504 calories for a full night of sleep. How are these numbers calculated exactly? It’s all about your individual metabolism. Metabolism is a process by which the body converts food into energy for use in daily activities. Even keeping your organs running, breathing, and circulating blood costs your body calories. Your basal metabolic rate (BMR), on the other hand, represents the number of calories you individually burn a day at rest, or while you’re sedentary. This includes sleeping and sitting. To calculate your BMR, you use an equation that factors in your sex, weight, and age using inches for height and pounds for weight. 66 + (6.2 x weight) + (12.7 x height) – (6.76 x age) = BMR for men

655.1 + (4.35 x weight) + (4.7 x height) – (4.7 x age) = BMR for women For example: A 35-year-old man who weighs 175 pounds and is 5 feet 11 inches tall would be: 66 + (6.2 x 175) + (12.7 x 71) – (6.76 x 35) = 1,816 calories. A 35-year-old woman who weighs 135 pounds and is 5 feet, 5 inches tall would be: 655.1 + (4.35 x 135) + (4.7 x 65) – (4.7 x 35) = 1,383 calories. The more mass your body has, the more calories you’ll burn while resting, sleeping, and doing other activities. Men tend to burn more calories at rest than women of the same weight because men typically have higher muscle mass . Muscle burns more calories at rest than fat does.

Factors that affect how many calories you burn Want to maximize your calorie torching in the overnight hours? A recent study uncovered that if you skip an entire night of sleep, you may actually burn an extra 135 calories over that period of time. Some participants burned as many as an extra 160 calories. But before you toss your pillow, understand that skipping sleep isn’t a great way to lose weight. Sleep loss over time may contribute to weight gain and obesity. It elevates certain hormone levels in the body, like cortisol. This hormone makes you hold onto extra fat. Not only that, but it may also increase your appetite and lead to a slower metabolism. What may help you burn more calories during sleep is taking measures to elevate your metabolism. Boosting your metabolism will help you burn more calories throughout your waking hours as well. What you should know: Eating late doesn’t slow your metabolism Eating before bed may cause a temporary increase in your metabolism through what’s called thermogenesis. And don’t worry about eating after 8 pm. Foods consumed after this time don’t magically make your gain more weight — it’s the mindless snacking that does. That said, eating large meals right before bedtime may make it harder to sleep. Exercise daily, incorporating strength training Having more muscle mass in general helps you burn more calories, even while you’re sleeping. So get in some exercise daily, especially strength training. If you have trouble settling down at night, try getting in your exercise several hours before bed. Losing weight may help Losing weight may help boost your metabolism as well. Fat burns fewer calories than muscle when at rest. If you’re overweight, consider making an appointment with your doctor or dietitian to discuss a healthy goal and a plan for how to get there. Caffeine may create a short-term boost Caffeine may increase metabolism slightly. At the same time, it has not been shown to help with long-term weight loss. And drinking caffeinated beverages before bed may make it hard to get a good night’s rest. Use supplements with caution Supplements that claim to boost metabolism should be used with caution or not at all. Some may contain unsafe ingredients. Even worse, they may not work. Always discuss any supplements you plan to take with your doctor. Certain health conditions may slow your metabolism Certain medical conditions, like Cushing syndrome and hypothyroidism, may slow your metabolism. This means you’ll experience less calorie burn at all hours and may even hold onto or gain weight. You doctor can perform simple tests, like a blood test, to rule out certain conditions. Then they can work with you to manage your condition and weight.