The Best Time of Day to Exercise

Workout timing can affect fat-burning, heart health and sleep

Exercising first thing in the morning is torture for me. I can do it if I must, but I prefer mid-morning through early afternoon. If I wait until too late in the day, I’m apt to get sidetracked or lose motivation. So I’ve long wondered if timing influences the effectiveness of exercise, and to what degree, or if there are times that should be totally avoided.

The scientific consensus: There is no perfect time of day to exercise that applies to everyone, but for those who can choose when to work out and wish to optimize the benefits, there are times that better facilitate weight loss, cardiovascular health and good sleep. All that can vary, however, based on gender, genetics, health status and other factors.

“There are ideal times of day to exercise to optimize health and performance goals,” said Paul Arciero, PhD, a professor of exercise physiology and nutrition at Skidmore College. “Although it’s equally important to stress there is no wrong time to exercise, because any exercise is better than no exercise.”

Best times for fat-burning and heart health

Physical activity in the morning, compared to later in the day, offers the best buffer against heart attacks and stroke, a new study in the European Journal of Preventive Cardiology concluded. The finding drew from data on 86,675 adults ages 42 to 78 whose health outcomes were tracked for eight years.

“It is well established that exercise is good for heart health, and our study now indicates that morning activity seems to be most beneficial,” said study team member Gali Albalak, a researcher at Leiden University Medical Center in The Netherlands. “The findings were particularly pronounced in women, and applied to both early birds and night owls.”

Other research offers much nuance on ideal workout times.

Earlier this year, Arciero led a study of 56 healthy and active women and men who worked out either in the morning or evening, and whose diets were scripted. The workouts followed a specialized four-days-per-week program of resistance training, intense aerobics, endurance workouts and stretching. All the participants improved their fitness, but some differences emerged:

• Among women, morning workouts were a bit better at reducing belly fat and lowering blood pressure: a 10% reduction on both measures versus 3% on each for evening exercisers.
• Evening exercise proved better for women to gain upper-body strength, power and endurance, and improved overall mood.
• For men, evening workouts were better than morning workouts for blood pressure, overall fatigue and body-fat burning.

What’s best depends on your goals

Arciero, author of The PRISE Life: Protein Pacing for Optimal Health and Performance, offered some broad perspective:

“Based on a growing body of evidence, including my own, morning exercise, between 6 and 11 a.m., enhances cardiovascular health and reduces [risk of] heart disease and stroke,” he told me. “However, late afternoon, early evening exercise is also known to produce the greatest improvements in muscular performance.”

John Higgins, MD, a cardiologist with UTHealth Houston and professor of cardiovascular medicine, provided his own general take on the existing research: If weight management or fat-burning are among your workout goals, then exercising in the early morning, before eating, is best, Higgins said. Morning exercisers are also less likely to skip a workout due to the pressures of the day, he noted.

“Also, working out in the morning wakes you up, releases endorphins which put you in a great mood, too, and you are more productive during the day,” Higgins explained in an email.

Times to avoid

Knowing when not to exercise is important, too. Physical activity at inopportune times can worsen an illness or run the risk of injury. Higgins suggests avoiding exercise when…

• You’re tired.
• You have a fever, are nauseous, dehydrated or otherwise ill.
• Your blood pressure is out of control.
• You’ve just had a big meal.
• There’s a thunderstorm.

Here’s a lesser-known good-to-know: While morning may be ideal for running or other aerobic workouts, lifting heavy weights before noon, especially if you’re out of shape or untrained, is linked to a higher risk of heart attack, Arciero said.

Don’t lose sleep over it

Physical activity is among the most important things you can do to improve sleep duration and quality, as I explain in my book, Make Sleep Your Superpower. However, some research has suggested that evening exercise can make it harder to fall asleep, though a 2019 review of studies on the topic found little firm evidence to support that suggestion.

“If doing sport in the evening has any effect on sleep quality at all, it’s rather a positive effect, albeit only a mild one,” said the leader of that review, Christina Spengler, head of the Exercise Physiology Lab at ETH Zurich, a research university.

There was one exception, Spengler and her colleagues noted in the journal Sports Medicine: When people do intense workouts within an hour of bedtime, it may take longer to fall asleep.

“The data shows that moderate exercise in the evening is no problem at all,” Spengler’s colleague Jan Stutz said in a statement.

Meanwhile, a 2019 study found that exercise timing can alter your circadian rhythm, the body clock that governs the sleep-wake cycle. Exercising at 7 a.m. or between 1 and 4 p.m. pulled peoples’ body clocks earlier, causing an earlier nighttime release of melatonin, a hormone that promotes sleepiness. Exercising between 7 and 10 p.m. pushed their body clocks back, causing the onset of sleepy time later at night.

“If one had to pick the best time to exercise for better sleep, I would say late afternoon or early evening,” said study leader Shawn Youngstedt, PhD, a professor at Arizona State University.

Researchers offer varying advice on this. Given the apparent effects on the body clock, Higgins advises avoiding late-day exercise. Arciero suggests doing any strenuous, high-intensity workouts before 6 p.m.

The bottom line

Overwhelming evidence points to undeniable physical, mental and emotional benefits of getting at least 150 minutes per week (22 minutes a day) of moderate or vigorous aerobic activity, plus two weekly sessions of strength training.

If you are free to choose when you work out, and you want the short answer for overall health, then the best time to exercise is probably in the early morning, before breakfast, Higgins says. Otherwise, choose a workout time that works for you, he and other experts agree, because you’ll be more likely to stick with your exercise routine.

“In short, the best time to exercise is whenever you actually exercise,” says Dianne Babbitt, PhD, an associate professor of health sciences at Cedar Crest College in Pennsylvania who researches, among other things, cardiovascular exercise physiology. “Choose a time that allows you to exercise on a regular basis, and that may be different depending on the day. Trying to figure out the best time based on other factors may create an unnecessary barrier that could become an impediment to regular exercise.”

I’m pleased to know that the case for early-morning torture isn’t so strong that I need to embrace it. I’ll keep working out sometime between mid-morning and early afternoon, simply because I enjoy it more. You should pick a time that best suits you, too, with this as your overriding principle: Any exercise time is better than none.

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I’m the author of Make Sleep Your Superpower: A Guide to Greater Health, Happiness & Productivity (paperback or Kindle version). Your support makes my health and wellness reporting and writing possible. You can sign up for emails when I publish on Medium, or join Medium to directly support me and gain full access to all Medium stories. Find me on YouTube, Instagram, Twitter, Linkedin. — Rob