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You don’t have to do keto or hot yoga to burn calories — your bod does that all on its own, even while you sleep.

Don’t hop into bed for the next week just yet. Getting shut-eye is def not the same thing as hitting the gym. But even while you snooze, your body is burning calories.

So, just how hard does your body work to burn calories while you dream about monsters and showing up to work naked? That’s based on factors like your weight, your metabolism, and the amount of Zzz’s you catch each night.

Here’s what goes down when you hit up sleepy town.

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In general, the more you weigh, the more calories you’ll burn while sleeping.

For example, a 125-pound human burns about 38 calories per hour while sleeping. TBH, that doesn’t sound like a ton. But when you multiply it by the recommended 7 to 9 hours of Zzz’s, that’s anywhere from 266 to 342 calories burned while snoozing.

A 155-pound person would burn closer to 46 calories per hour (322 to 414 calories per night) while sleeping. And a 185-pound person could burn about 56 calories per hour (392 to 504 calories per night).

Bottom line: Even when you sleep, your body’s always doing something.

So, how do you calculate your unique calorie-burning sleep abilities?

It all boils down to your metabolism (the process where your body converts food into energy you can use to get sh*t done). Even just breathing, moving blood around, and keeping your organs running in tip-top shape requires your body to expend energy. This burn calories.

Meanwhile, your basal metabolic rate (BMR) represents the number of calories you burn at rest, which, yes, includes when you watch “Friends” reruns or are passed the eff out on the couch.

These equations offer estimates, not concrete stats, and are based on the idea that men tend to burn more calories at rest because they tend to have a naturally greater muscle mass. Muscles burn more calories at rest than fat.

If you have less or more muscle than the average male or female, you might consider calculating both figures and going with the number in between them. You can also invest in a heart rate monitor to track your calories burned more accurately than an equation can.

Sorry, but running in your dreams won’t make you burn more calories while you sleep — even if you’re a literal boss all night.

If you want to up your BMR, you can take measures to boost your metabolism, like exercising and eating healthfully. Doing so will also cause your body to burn more calories all the time, whether you’re cruising through dreamland or jogging through the neighborhood.

Here are a few other factors that can affect your metabolism and impact your sleep burn.

Late-night nomming

There’s nothing like 12 a.m. pizza, amiright? You may have heard that eating before bed will slow your metabolism, but science says that’s not actually the case.

In fact, those midnight munchies can cause a temporary spike in your metabolism through a process called thermogenesis (the dissipation of energy as heat after you eat).

Basically, don’t worry too much about when you eat as much as what you eat. Snacking a lot at any time of day can lead to weight gain and a slower metabolism.

Muscle gains

The more muscle mass you have, the more calories you’ll burn. So fitting in daily exercise, especially strength training, will cause you to burn more calories while you snooze (and while you hit snooze… for the tenth time).

Drinking coffee after coffee

Some research suggests that caffeine gives your metabolism a temporary mini-boost that may extend into your sleepy-time hours.

But don’t start chugging Red Bulls or cappuccinos just yet. There hasn’t yet been enough research to confirm that caffeine has a long-term effect on weight loss.

Not enough Zzz’s

Whether it’s because of work overload, insomnia, or late-night Netflix marathons, insufficient rest can boost your levels of the stress hormone cortisol.

Cortisol causes your body to hang on to extra fat, makes you hungrier (and hangrier), and slows your metabolism. Plus, a 2017 study found that longer sleep is associated with lower BMI and healthier metabolic profiles.

Certain health conditions

Certain health conditions, like hypothyroidism and Cushing syndrome, can slow down your metabolism. This can lead to weight gain and slower calorie burn, even when you’re eating healthy and exercising.

If you think you might have a health condition that impacts your metabolism, talk to your doctor. They can evaluate you using tools like blood tests to pinpoint certain conditions.

Whether you burn 500 calories per night or 1,000, pat yourself on the back — your body works hard. But if you’re looking to burn more calories while asleep and around the clock, there are some steps you can take.

The pros recommend working out to boost your metabolism. Fitting in at least 75 minutes of vigorous exercise (like running or cycling) or 150 minutes of moderate exercise (like brisk walking) per week can help. Strength training will also help your bod build the muscle needed to get that burn.

The other most important factor? What you eat. For the biggest metabolic boost, go for nutritious foods like fresh vegetables and lean proteins and try to avoid eating a lot of processed foods or added sugars.

Fitting in enough sleep — that means 7 to 9 hours — can also rev up your metabolism.