You planned to work out earlier in the day, but life got in the way. Now you finally have time to squeeze in a workout, but it’s getting close to bedtime — and you’re worried that a late-night workout will mess with your ability to fall asleep. You don’t want to be on a post-exercise endorphin kick at midnight, but you don’t want to skip a workout either — so what should you do? Here’s how to keep a late workout from interfering with your zzz’s.
How Exercise Affects Your Sleep Habits
For the most part, exercise and sleep have a positive impact on one another — research suggests people who sleep better tend to exercise, and vice versa.
That said, exercise — especially high-intensity exercise — affects the body in a way that can make it tricky for some of us to power down quickly afterward.
When you work out, your metabolism temporarily increases, which also brings an increase in nervous system activity, says Jeffrey Potteiger, Ph.D., graduate school dean and professor in the department of movement science at Grand Valley State University in Grand Rapids, Michigan. These increases can keep your body in a heightened state, which delays your body’s process of preparing for sleep.
“It takes two to three hours to power down after a workout,” Potteiger says. But there are a few simple strategies you can use to help your body get sleep-ready after a late-night exercise session.
1. Cool Down (Literally)
As your body prepares for sleep, your core body temperature drops. This signals to your brain that it’s nearly bedtime, says W. Chris Winter, M.D., sleep specialist and author of The Sleep Solution: Why Your Sleep is Broken and How to Fix It. Your body’s sleep-inducing chemicals won’t kick in until your body temperature drops — so if you’re still sweating from your late-night HIIT workout, that could delay your bedtime.
To keep heat from messing with your sleep, focus on cooling down as quickly as possible after your workout. Winter suggests taking a lukewarm shower and drinking a glass of cold water. And make sure your bedroom environment is cool enough to encourage sleep. According to Winter, most of us fare well when temps are right around 68° F.
2. Minimize Light
Light plays a major role in sleep regulation, and blue light, in particular, has a powerful effect on your circadian system. Blue light blocks the production of melatonin, the hormone that regulates your sleep-wake cycle and helps you feel sleepy at bedtime.
In the morning, blue light from the sun helps wake you up. At night, however, blue light sends the wrong message: “It convinces your brain that the sun is rising again, which tends to block melatonin,” Winter says.
Unfortunately, blue light is everywhere: your phone, your laptop, your tablet, your TV, and fluorescent and LED lighting.
Ideally, you should shut off screens about three hours before bedtime. If that’s not possible — maybe you stream your workouts online, or you just can’t resist scrolling through social media before bed — Winter recommends wearing blue-blocking glasses for three hours before bed.
Research suggests this timing can help your sleep habits. One study found that adults who wore blue-blocking glasses for three hours before bed saw greater improvements in sleep quality by the end of three weeks than those who didn’t. And a study of teenage boys who used blue-blocking glasses during evening screen time revealed similar findings.
Research suggests that meditation can affect sleep habits. One study found that sleep-disturbed adults who followed a six-week mindfulness meditation program saw greater improvements in sleep quality, mood, and daytime energy than those who followed a six-week sleep education program.
To get started with meditation, try downloading an app like Headspace, or simply take five minutes after your workout to sit in a quiet area and focus on relaxing your muscles. Start from your toes and progress to your head, Winter says.
Or, choose an activity that you find relaxing and meditative — “something you can get in the habit of doing as soon as the exercise is over to paint a picture for your nervous system that it’s time to start turning off,” Winter says. Just make sure you choose an activity that will calm you down, not rev you up — in other words, this may not be the best time to “relax” by catching up on The Walking Dead.