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You probably think diet and exercise matter most when it comes to reshaping your body. And while they certainly are important, there’s another lifestyle habit that can make all the difference in your journey: sleep.
“Sleep affects absolutely everything — from heart rhythms to hair and everything in between,” says Ellen Wermter, board-certified family nurse practitioner in Charlottesville, Virginia, and spokesperson for the Better Sleep Council. “It is the ultimate multipurpose tool for optimizing systems and improving overall health, metabolism included.” In fact, it can potentially cause you to gain weight and make it even tougher to lose weight and body fat.
How Sleep Is Connected to Body Composition
Poor sleep is connected with numerous health issues, weight gain being one of them. “Weight gain is a well-documented consequence of sleep restriction,” says Eve Van Cauter, Ph.D., professor of medicine and director of the Sleep, Metabolism and Health Center at the University of Chicago and chair of the Sleep Number scientific advisory board. That link is stronger if you’re not getting the proper amount of sleep versus if you’re frequently waking throughout the night and not getting the quality of rest you need. “The increase in hunger and appetite leads to excess food intake, particularly snacks,” she explains.
The blame, in part, can be placed on changes in two hormones that affect appetite: leptin and ghrelin. With poor sleep, ghrelin increases while leptin decreases. “Ghrelin causes you to crave quick sugars that leave you hungry and grumpy, while leptin is responsible for satiety so you know when to put the brakes on eating,” Wermter says.
Think of ghrelin as a little gremlin that entices you to make poor food choices and shows up more often when you’re short on shut-eye. As a result, you’re more likely to get the munchies when you’re sleepy. “When your energy feels low, you might think that adding fuel (aka food) to your body will help,” Wermter says.
And while this may be obvious, if you’re not sleeping well, you probably won’t feel like exercising. The correlation, however, goes both ways. “While it may be easier for someone who is well-rested to make the decision to go work out, exercise also has a tremendous positive effect on sleep,” Wermter says.
Getting the Sleep You Need to Achieve Your Goals
Ready to make it a priority? The National Sleep Foundation recommends that adults log between seven and nine hours a night, though individual needs may vary. “Population studies from around the globe have shown that adverse associations between short sleep duration and health consequences are not detectable when sleep is seven hours or more,” Van Cauter says.
So how do you know how much you need? To figure out your body’s needs, take a break from any constraints you place on your bedtime, turn off the alarm clock and let your body naturally go to sleep and wake up. While you’ll initially sleep longer (you’re snoozing off debt, after all), your schedule will start to stabilize after one to two weeks of doing this, and that’s your personal need, Van Cauter says.
Fortunately, doing things like keeping your schedule consistent can help you log the Z’s you need. That means not only going to bed at the same time every day but also getting up at the same time every day. “This drops an anchor in your circadian rhythm and keeps your systems in sync,” Wermter says. She also recommends getting outdoor light daily, especially in the morning, and logging regular exercise.
Pay attention to diet, too, because what you eat before you go to bed can affect sleep. Alcohol, heavy meals and caffeine can make it hard to fall asleep, according to the National Sleep Foundation. And don’t forget about setting up a sleep-friendly room, which includes keeping your room cool and dark and using a comfortable bed, Van Cauter says.
Getting the sleep you need won’t magically change your body overnight. But with enough shut-eye on board, meeting the goals you’ve set will be easier to achieve.