Feeling Sleepy After Working Out? Here’s Why

It’s normal for your muscles to feel tired after a workout, but are you changing out of your gym clothes only to feel like you need to take a nap? Feeling sleepy after a workout is not only inconvenient, it’s potentially a sign that you’re not treating your body as well as you should. Read on for the reasons you might be tired after exercising, plus ways to feel more energized.

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Reasons Why You Might Feel Sleepy After a Workout

1. You’re Not Getting Enough Sleep

Ahh, sweet sleep. We love it, but most of us aren’t getting enough of it, and that’s a problem. In addition to the obvious fatigue that’s caused by a lack of sleep, not getting enough zzz’s can also negatively impact other parts of your life and health, including slowing down your metabolism. Our metabolism is what keeps all of our cells functioning. "That means your heart, your brain, your blood flow, your organs—they all rely on your metabolic functioning to keep you alive,” says Samantha Cassetty, RD. “And one prime lifestyle factor that is deeply tied to your metabolic functioning is your sleep." Sleep deprivation has a profound impact on your body’s internal metabolic processes, and shortchanging your sleep for even just one night (!) can mess up your hormones and increase your appetite. "If you sustain poor sleep habits over time, it ups the chance of weight problems and other health concerns," Cassetty told us.

2. You’re Dehydrated

We know how important it is to drink water. But if you’re working out and feeling ultra-fatigued after, you might not be drinking enough. A small 2012 study, published in the Journal of Nutrition, tested mood, concentration and mental skills in 25 women who either were given enough fluids to remain optimally hydrated or were induced into a mildly dehydrated state. Researchers found that being dehydrated caused headache symptoms, loss of focus, a sense of fatigue and low mood both at rest and during exercise.

3. You’re Not Eating the Right Foods to Fuel Your Body

Food isn’t just delicious; it’s also the fuel that helps your body break down fats and sugar into energy. If you’re “fueling” your body with processed foods with little to no nutritional benefit, you’re probably not going to feel great after exercising, since you’re depriving your body of the energy that comes from eating the right stuff.

Note that there could be other underlying medical causes for post-workout fatigue. If you suspect that something other than the above reasons is the culprit behind your sleepiness, reach out to your doctor.

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4 Ways to Prevent Post-Workout Fatigue

1. Prioritize Sleep

“Sleep is your body's guaranteed rest period,” says Courtney Roselle, a personal trainer and founder of Grace Fitness. “It is your time for your muscles to recover and to put your body on reset, both mentally and physically.” So, make sure that you clock in at least seven hours after a workout, got it?

2. Stay Hydrated

If you’re not accustomed to drinking water throughout the day, it’s time to start. Whether you mark off water goals on your bottle or set an alarm on your phone to remind you to take a few sips, hydration is one of the best—and easiest—things you can do for your body. It’s also tempting for folks who work out in the morning to go straight for coffee after a sweat sesh. Bad idea, says personal trainer David Middleton from Punch Run Lift. “I see a lot of people reaching straight for a coffee after a workout and that’s a big no-no from me. Rehydrate your body with water first before any caffeine.”

3. Reconsider Your Diet

“The food you eat within the first few minutes after a workout is one of the most important and underrated parts of training,” says personal trainer Lisa Reed. In order to help your body recover faster, as well as repair and build new muscle tissue, you’ll want to refuel soon after working out with a small amount of carbohydrates and protein. How soon? Research has shown that consuming a post-exercise meal immediately after working out (like, within 15 minutes) is better than eating an hour afterward, Reed tells us. With that in mind, here are three delicious snacks to maximize recovery.

Hummus and Whole-Grain Crackers
“After a workout, your body likes carbohydrate-containing foods because it's burned through all its energy stores,” nutritionist Lindsey Joe explains. To replenish these stores (aka glycogen), top a couple of whole grain crackers with protein-rich (and totally delicious) hummus.

And not just the whites. “Egg yolks contain several vital nutrients for brain and bone health,” says Asche. She suggests packing a few hard-boiled eggs into your gym bag for a quick and easy source of protein, teamed with a slice of whole-wheat toast for additional carbs post-workout.

Low-Fat Chocolate Milk
For those who find it hard to eat right after exercising, the American Council on Exercise suggests trying liquid foods instead of solids. And chocolate milk is a great choice, thanks to its tasty mix of carbs, protein and water. (Just go easy on the sugar.)

4. Cool Down After Exercising

When we finish a workout, our first instinct is to get out of the gym as quickly as humanly possible. But cool-down exercises can be just as important—if not more important—than the actual workout. According to the American Heart Association, “After physical activity, your heart is still beating faster than normal, your body temperature is higher and your blood vessels are dilated. This means if you stop too fast, you could pass out or feel sick.”

Cooling down by stretching also reduces the buildup of lactic acid, which can help prevent cramping and stiffness. These exercises can also prevent—or at least minimize—delayed onset muscle soreness, or DOMS, the pain and stiffness in the muscles you feel anywhere from 24 to 72 hours after exercise. “One of the biggest post-workout mistakes that I see people make is skipping a cool-down stretch or leaving before the end of a group fitness class,” says Jonathan Tylicki, certified personal trainer and director of education for AKT. “Stretching will help prevent soreness, relax the nervous system, promote mobility and flexibility and can even improve your next workout.”

Here are eight cool-down exercises to try.

sarah stiefvater
Sarah Stiefvater

Wellness Director

Sarah Stiefvater is PureWow's Wellness Director. She's been at PureWow for ten years, and in that time has written and edited stories across all categories, but currently focuses...
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