Between working your 9-to-5 gig, prepping and munching on three-plus meals, cleaning up your home, and caring for your kids (or fur babies), your daily schedule is probably pretty jam-packed. And that means the only time you have to squeeze in a treadmill run or working out at night may be right before climbing into bed.
But can all that late-night huffing and puffing actually do more harm than good for your sleep? Ahead, learn how working out at night can affect your sleep and what you can do to ensure your sweat sessions don’t ruin your slumber.
Is working out at night bad for your sleep?
It may seem like a simple question, but the jury’s still out on whether it’s harmful to exercise before bed, says Kin M. Yuen, M.D., M.S., a professor of sleep medicine at the University of California San Francisco and a public safety committee member for the American Academy of Sleep Medicine. Currently, research findings on the topic are mixed, the study methodologies are inconsistent, and there are so many factors — including activity intensity, duration, and modality — that make it tough to pin down a specific “yes” or “no” answer, she explains.
In general, exercise can help improve your zzzs, particularly if you’re dealing with chronic sleep disturbances. In a small study on older adults with insomnia, researchers found that four months of aerobic exercise training significantly improved sleep quality and reduced daytime sleepiness. “Working with clinical patients who have insomnia, we routinely recommend a moderate degree of exercise [for treatment] such as restorative yoga and Tai Chi,” says Dr Yuen. And in healthy adults, a single bout of evening exercise has been linked with a significant increase in rapid eye movement (REM) latency (aka how long it takes you to reach REM sleep after drifting off) and slow-wave sleep (the deepest phase of non-rapid eye movement sleep), according to a 2019 meta-analysis published in Sports Medicine.
That said, working out at night may also come with a few drawbacks. During exercise, you activate the sympathetic nervous system, which causes your heart rate to increase and your airway muscles to relax to improve oxygen delivery throughout your body, according to the Cleveland Clinic. Simultaneously, your core body temperature rapidly rises, which generally is not favourable for a good night’s rest, says Dr Yuen. Sleeping with a high body temperature is similar to snoozing in a sauna: “If you’re sleep deprived enough, you can fall asleep, but the quality of your sleep is going to be impaired,” she explains. “You may have more trouble going to sleep and also may wake up more often.” In fact, folks who have high core body temperatures when they doze off tend to spend more time awake throughout the night than those with lower temps, says Dr Yuen. If your elevated heart rate also doesn’t quickly return to normal levels post-workout, you may also be more likely to experience insomnia-like side effects, says Dr Yuen.
The type of exercise may also matter. Working out at night with a “vigorous” activity, such as running or high-intensity interval training, may impact your sleep more heavily than a chill session. The 2019 meta-analysis found that higher evening exercise intensity was associated with lower sleep efficiency and more sleep after wake onset (the number of minutes you’re awake after initially falling asleep). Plus, high-intensity exercise ending 30 minutes to four hours before bedtime has been found to decrease REM sleep, which is needed for your brain to consolidate and process new information, according to a 2021 meta-analysis. “In theory, running could cause more inflammation and may cause more muscle repair that’s needed to be done [during sleep],” says Dr Yuen. “That may cause difficulty with sleep, either decreasing the amount of sleep or having more trouble going to sleep.”
People suffering from insomnia are particularly likely to experience negative consequences from working out at night. These folks often have fairly high levels of cortisol (a hormone that puts your body on high alert) before bed — up to four times the recommended amount, says Dr Yuen. “So for those individuals, if we add vigorous activities on top of it, whether it is half an hour to an hour before bed, probably is not a good thing,” she adds.
How to exercise at night without ruining your sleep
Remember, the current research is inconclusive, so you’re not destined for poor sleep if you exercise before bed. But if you’re worried about your after-dark workouts disturbing your slumber, use these pointers to keep your zzzs on track.
Keep track of your workouts and sleep performance
If you’re going to work out at night, make sure to keep a journal of your evening workouts (including the activity, intensity, time, and duration) and how you feel in the morning, suggests Dr Yuen. Ask yourself if you feel well rested, and try to recall how long it took you to fall asleep and how many times you woke up throughout the night.
You can also use your fitness tracker to log your heart rate and get objective data on your sleep performance, she says. Then, use those metrics and your notes to guide your future workout choices and pick activities that will support your shut-eye.
Stick with low-intensity activities
Since vigorous workouts can jack up your heart rate and body temperature, which may make it more challenging to fall asleep and stay asleep, perform your intense workouts (think: marathon training, powerlifting) during the afternoon and stick with mellow movements, such as yoga and stretching, in the evening, suggests Dr Yuen. Some research suggests that speeding up your heart rate by 26 beats per minute while running can disturb sleep, she adds. “But when people’s heart rates only went up about 10 beats per minute, they had fewer symptoms of insomnia, sleep disruptions, and awakenings.”
Stop your workouts at least 30 minutes before bed, and don’t skip your cool-down.
Ideally, you’ll want to end your workouts between 30 minutes to an hour before bed in order to allow your heart rate to slow down and body temperature to cool, says Dr Yuen. But if your heart rate is typically high to begin with, you’ll want to stop exercising even sooner, she says. “I think that’s when two-and-a-half to four hours is routinely being recommended,” she adds.
That said, you may be better off taking the time to complete a longer cool-down session than you might do during your afternoon workouts. “The studies seem to support a longer winding-down period,” says Dr Yuen. “It allows for the calming down of the entire body system, to cool the body temperature and allow the heart rate to slow down, [which] seems to have some benefit of encouraging better quality sleep during the night.”
Refuel with the right snacks.
After a tough workout, you’ll want to nosh on foods rich in protein and carbohydrates 30 minutes to an hour after exercise to refill your energy stores and repair muscles that were broken down, as Shape previously reported. To boost the odds of a good night’s sleep, opt to refuel with a balanced munchie that may also promote shut-eye, such as yoghurt (which contains tryptophan, an amino acid that can help promote sleep) or a banana (which contains tryptophan and melatonin) with nut butter.
Avoid testing new workouts.
As mentioned, the need for extensive muscle repair after a tough workout can lead to sleep disruptions. By sticking with workouts your body’s familiar with, you may reduce the amount of tissue recovery your body needs, says Dr Yuen. “If someone routinely runs two miles every day, then perhaps nothing is out of the ordinary and the body’s not as challenged, so it doesn’t have to do with much repair work,” she explains. “But if who’s new to running decide to try it [at night], that may create more muscle stress and they may have more inflammation…That may affect what their sleep quality is going to be like that night.” In other words, don’t try a HIIT workout for the very first time just two hours before you hit the hay.
This story first appeared on www.shape.com
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