Many people think of exercise as a morning thing—a dawn jog through the neighborhood, or 30 minutes at the gym before work.
But as experts learn more about America’s serious deficits in sleep and exercise, they’re reconsidering the best time of day for people to be active.
Conventional wisdom suggested just-before-bedtime workouts interfere with sleep. But new research suggests that evening workouts, even intense ones, don’t disrupt sleep in healthy young and middle-aged adults without sleep disorders.
“Sleep is good for exercise, and exercise is good for sleep,” said Kelly Waters, MD, an expert in sleep medicine at Corewell Health.
But problems can start when people sacrifice one for the other.
“The recommendation is that people need between seven and nine hours of sleep a night. So if you’re getting up at 4 a.m. to get on the treadmill, even though you were up until midnight, that’s not good,” she said. “You’re better off sleeping. Otherwise, you rob yourself of focus and restoration for the rest of the day.”
Often, when people are training up for an event, such as a marathon, they give up sleep to gain the additional hours of training.
That’s a mistake, Dr. Waters said.
“We know that athletes need more sleep,” she said. “At least seven and up to 10 hours a night to perform at their best and recover adequately.”
It’s important to understand how sleep benefits our bodies.
“We need the deeper sleep stages for that rest, recovery and muscle repair,” she said.
During the slow-wave sleep, “growth hormone is released, which is really reparative for muscle. The more exercise you get, the more that deep sleep helps.”
Finding your best routine
For many, morning workouts feel right.
“The body has many of the right cues going, in terms of heart rate and peak levels of cortisol,” Dr. Waters said. “And many people say it refreshes their mind.”
But it isn’t for everybody. Some people just don’t like it, choosing to exercise later in the afternoon or the early evening.
That works well for those who still want to have a few hours to wind down before bedtime.
And for people who typically don’t have any trouble sleeping, working out closer to bedtime may be just fine. Because heart rate, temperature and blood pressure drift downward after a workout, it can even be conducive to sleep.
“That temperature drop can kickstart your path into sleep,” Dr. Waters said.
She also recommends rethinking exercise into smaller chunks.
“You don’t have to work out a full hour to get exercise’s sleep benefits,” she said.
Current guidelines call for 150 minutes of exercise per week, or about 30 minutes per day, five days a week.
“Try walking for 20 minutes on your lunch break, stretching or doing a lightweight routine or yoga in the evening,” Dr. Waters said.
There’s a different set of calculations for those who sometimes have trouble sleeping or staying asleep. That’s an occasional problem for about 30% of the U.S. and a severe problem for about 10%.
In those cases, she said, “hyping yourself up right before bed might not be the best.”
Yoga, stretching and breathing routines can be helpful.
“It depends on how intense a yoga routine is and how practiced you are,” Dr. Waters said. “If it’s your first time trying certain moves, there’s a lot of trial and error and it’s not going to be relaxing.”
Dr. Waters also said it can be helpful to explore simple breathing exercises.
Self-centering breathing, where you focus on breathing in and out—often done while sitting up in a chair—can help you settle down and put the day away.
“It’s great for when it’s time to turn out the lights, but your mind is still awake,” she said.
Another approach that works when you’re in bed: Count your breaths.
“(This) leads to more rhythmic breathing,” she said. “It’s kind of like that last step before nodding off. The first stage of sleep is called the hypnic stage, and that kind of rhythmic breath counting is almost like self-hypnosis.”
For those who struggle to fall asleep or stay asleep but want to work out later? You can develop good sleep hygiene. It just requires patience and consistency.
In cognitive behavioral therapy for insomnia, “we’re learning to build the habit with a set time and place for that bedtime routine,” Dr. Waters said.
For many, those routines might include writing in a journal, reading or stretching. It may take two to three weeks of consistent practice for a routine to become a habit and six to eight weeks to feel the full benefit.