How to exercise before sleep at night without dooming your REM cycle. Keep in mind these important caveats.
Twice a week after he gets off work, GQ staff writer, resident Bachelor aficionado, and cranky geezer Jay Willis straps on his ASO ankle stabilizers, laces up some Nikes, and partakes in a couple hours of old man pickup basketball. (Technically he’s only old compared to me, which I will never let him forget.) Afterwards, Jay “Bob Cousy” Willis heads home, showers, and attempts to fall asleep. But he’s often restless, lying wide awake, reminiscing about his glory years before the stinkin’ three-point line was invented. Jay is not alone, at least on one front: a cursory search for “can’t sleep after nighttime exercise” reveals plenty of other fit-but-sleepless souls. It’s true that exercise does a number of things to the body that keep us from falling asleep. You’re sweaty, for one, which is mostly just uncomfortable, and as your adrenaline is pumping, your core temperature and heart rate are elevated. In theory, those fluctuations shouldn’t last all that long after the conclusion of a workout, but there are plenty of exceptions on a person-to-person basis.
To bridge the gap for nighttime exercisers who want to enjoy all the sleep-related benefits of their workouts, there’s a solution. A magic number: 90. As in, your body needs a full 90 minutes to decompress between workout and bedtime in order to unlock the sleep benefits of a workout. High-intensity exercise, like interval training, can otherwise throw you off. But assuming you allow for that hour-and-a-half, says Alicia Romano, a registered dietician at Tufts Medical Center, “Not only does evening exercise not affect sleep, it seems to help people fall asleep faster and spend more time in deep sleep.” Melissa Majumdar, a licensed dietician and former personal trainer, notes that my colleague Jay isn’t necessarily a freak of nature if he’s lying down, wide awake, after the 90-minute magic number passes by. “The hour-and-a-half is mostly a guideline,” she says. “If someone does get uber-competitive and riled up from a basketball game, and they can’t fall asleep within a few hours, then let’s change up that routine!”
For people whose nighttime exercise is non-negotiable, there are a few tangentially-related-to-exercise modifications to keep in mind. Romano says it’s worth checking out the caffeine content of any pre-workout supplements you might be ingesting after dark: “In general, caffeine takes three-to-five hours to metabolise in the body, and for those that are slower at metabolizing caffeine, that time is even longer. Most individuals will have trouble sleeping if they take a caffeine-heavy pre-workout supplement before an evening workout.” Romano also warns that while there isn’t an abundance of research available, a large late-night meal may keep you up longer. For that reason, eating dinner before a nighttime workout—rather than after—might be worth a try. (A smaller midnight snack is still no biggie.)
Lastly, anyone struggling to catch their zzz’s post-workout would be wise to take some deep breaths. Majumdar says that whether you’re a child or an adult, an essential part of having a bedtime routine is a cool-down period, leading to the natural release of the sleep-regulating hormone melatonin. Play relaxing music on the drive home, dim the lights in your bedroom/kitchen, and develop a “stretching or yoga routine that helps with recovery and also calms the whole nervous system down.” In other words, go full Enya with it. Equipped with the knowledge of the 90-minute post-workout magic number, some slight dietary switch-ups, and a renewed focus on chilling out, there’s hope yet for Jay and others in his position. Exercise and sleep really can be natural partners.