When Is the Best Time of Day to Work Out?

Allie Volpe
·5 min read

Among the many weighty decisions we make daily ("Should I wear my nice mask today?" “Can I put that email off until tomorrow?”), perhaps none alters the course of the day like deciding when to work out. The timing of your reps can impact your sleep schedule, stress levels, and even your gains. Hit the gym too early, and you risk feeling sluggish from a lack of sleep; go for a run too late, and you’ve missed seeing actual daylight. But with only so many waking hours in the day (a good portion of which are consumed by Zooms and feeding yourself, lately), squeezing in a workout can be a matter of day-planner Tetris. It's tempting to just be happy you're working out at all. But before you do that, consider the potential benefits and pitfalls of what time you work out.

Morning sweat is best—as long as you’re getting enough sleep

Studies show a.m. workouts tend to offer the greatest benefits. Not only are you less likely to be interrupted by life in the hours immediately post-slumber, exercising in a fasted or semi-fasted state (meaning you’ve eaten only a light breakfast, if at all) burns the most fat, according to a 2016 study. “You're going to be burning some of your stored energy, versus if you wait until later in the day,” says Christopher Lundstrom, a lecturer of sport and exercise science at the University of Minnesota. “If [later in the day] you go to Starbucks and have a vanilla latte, and then you work out an hour later, you're burning the vanilla latte, as opposed to tapping into those stored carbohydrates or stored fat.” Research also shows morning exercise can curb food cravings throughout the day.

From a stress-management perspective, morning exercise poises you for serenity. As a part of the cycle of our circadian rhythm, levels of the stress hormone cortisol reach their peak in the morning, priming us physiologically and mentally for the upcoming day, says Shawn Youngstedt, a professor in the College of Nursing and Health Innovation and College of Health Solutions at Arizona State University. By working out in the morning, you’re taking advantage of this boost of cortisol and performing when your body is supposedly most alert, as opposed to the evening when our cortisol levels are lower as we prepare for sleep. During exercise, our body also releases cortisol and when we wrap up our workout, cortisol levels drop off, allowing for a chill emotional state to start the day.

Plus, if you’re an athlete who races or competes in the morning, training during that hour prepares your body for A.M. performance, Lundstrom says. If this sounds like a complete non-starter, reconsider! Habitual pre-sunrise sessions can actually make you more of a morning person, shifting your circadian rhythm so your body accommodates an early bedtime and wake-up. Just be sure you're actually getting enough shut eye—sleep is really good for you, and you shouldn't cut into it just to work out.

There's a case for afternoon exercise

Not all circadian rhythms are alike and you may not be naturally predisposed toward rising and grinding. If you’re cutting into your sleep so you can squeeze in a pre-work run, “You are likely to struggle with morning exercise performance and have depleted energy levels for the rest of the day,” says Penny Larsen, associate research fellow at the University of Wollongong School of Exercise, Science and Sport. And you’re not getting the most out of your workout if you’re sluggish and exhausted.

For night owls, there’s nothing wrong with sleeping in a bit and hitting the gym in the afternoon. In fact, exercising between 1 p.m. and 4 p.m. is just as effective at shifting your circadian rhythm forward (that is, making you feel naturally sleepy earlier) as working out at 6 a.m., Youngstedt found.

“That was a surprising result,” he said. “We think it might have implications because a lot of night owls, they're not that keen about getting up and exercising in the morning, and so those people might do well to do it in the afternoon.”

If you’re looking to PR or want to perform your best, consider scheduling a workout for the afternoon. Research shows the greatest strength increases happen in the afternoon. “Your body is fully awake, it's fueled, you're not just transitioning out of being asleep,” Lundstrom says.

Late workouts are not as bad as you may have heard

The long-held belief that nighttime workouts make it harder to fall asleep is but a myth, Youngstedt says. (He personally found in a recent study that working out two hours before bedtime didn’t negatively affect sleep in most participants.) So if an evening trip to the gym is the most conducive to your schedule, consider squats a viable component of your wind-down routine.

One thing that is proven to disrupt sleep, though, is eating a lot. If you're accustomed to crushing a healthy serving of protein after you exercise, this could be a problem. Larsen suggests eating a larger meal before your workout and a smaller one post-exercise so as to not disrupt your sleep with a full stomach.

Figure out your own rhythms

Although early morning exercise comes with some distinct benefits, the bottom line is that you should get your sweat any time you want as long as it’s convenient for you. Better yet, figure out how to fit it in while getting enough sleep, then make it a consistent habit. “It’s not that there’s an inherently best time of day to exercise, but it all goes together: Your sleep, your nutrition, your exercise,” Lundstrom says. “So having fairly regular patterns will help you regulate your energy levels and your sleep.”

It might be fewer than you expect.

Originally Appeared on GQ