Exercise is a key way to stay healthy and live a longer, more productive life. It’s beneficial in several ways, not least of which is its ability to promote good sleep. Tiring yourself out with a tough workout is a great way to help your body feel ready for sleep when it’s time to go to bed. And regular physical activity can help you stay asleep longer and wake up feeling more refreshed in the morning.
However, the time of day you exercise can impact that quality of sleep.
How Exercise Impacts Sleep
Dr. Steven Holfinger, sleep medicine expert at the Ohio State University Wexner Medical Center in Columbus, says that “exercise enters you into an activating state that makes it harder to fall asleep temporarily.”
Exercise’s impact on sleep varies from person to person and is dependent on many factors, including your own sleep-wake cycle, also called the circadian rhythm. This natural 24-hour cycle of changes in the body regulates sleep, as well as hormones and body temperature.
“Body temperature rises from the moment we awaken in the morning and continues to do so until just before our sleep period when it precipitously drops,” says Dr. Peter Fotinakes, medical director of the Sleep Disorders Center at St. Joseph Hospital in Southern California. “The sense of feeling physically sleepy occurs with this drop in body temperature, so things that influence body temperature also influence sleep.”
Therefore, “aerobic exercise sufficient to increase core body temperature may exert an influence when we fall asleep. Raising the core body temperature too close to sleep produces stimulation and interferes with sleep.”
On the flip side, if you exercise long enough before bedtime, so that your body temperature has time to fall, that can actually help you sleep better, says Dr. James Ting, a sports medicine physician with Hoag Orthopedic Institute in Southern California and team doctor for the Los Angeles Chargers football team. “The gradual decline in core body temperature that occurs post-exercise helps to trigger drowsiness and facilitate sleep. Exercising in the morning or afternoon will allow that decline in core temperature to occur at night just in time for bed.”
Exercise also stimulates the release of endorphins, the feel-good brain chemicals responsible for the euphoric feeling often called “runner’s high.” This is great for boosting mood and may support better brain health, but “the release of endorphins that occurs with exercise may also negatively impact your ability to fall asleep following evening exercise if there’s not enough time for the associated stimulatory effects to dissipate prior to bedtime,” Ting adds.
And Holfinger notes that there’s some evidence that “exercising closer to bedtime is more likely to shift your circadian rhythm later, similar to how bright light at night can shift your rhythm, making your body want to go to sleep and wake up at later times.”
The Best Time to Work Out
Of course, with busy schedules, the best time to work out is what fits best in your schedule. Exercising before bed is still better than not exercising at all. As Dan Daly, a coach, trainer and co-creator of the Equinox Group Swim Program EQXH2O based in New York City, puts it, “the best time of day to exercise is the time when you can fit it in.”
And there may be other factors to consider, like climate or fitness goals. Looking at performance standards, he notes that “many world records have been broken in the afternoon,” and depending on where you live, that might also influence the best time of day to train. In cooler climates you may want to go later in the day when the air has warmed more. In hotter climes, early morning or evening when the sun and mid-day heat is not a factor may be preferable.
However, when it comes to working with your body’s circadian cycle, mornings and afternoons may be best. “There’s still some debate as to the optimal time of day to exercise, but it’s generally felt that working out in the morning or afternoon, rather than the evening, may be ideal in regards to sleep,” Ting says.
Holfinger adds that “mid-afternoon is often the best time” for exercise because for most people, mid-afternoon is “when your circadian rhythm’s alerting signal has relatively dropped and the post-lunch drowsiness may be setting in.” This process causes decreased focus and alertness, so that time is “likely better spent doing something active and alerting such as exercise.”
But, “the closer you get to bedtime, the more likely the exercise is to keep you awake,” Holfinger says. Generally, we recommend avoiding rigorous or stressful activities in the couple hours leading up to bedtime.”
[READ: How to Get a Good Night’s Sleep.]
The Best Time Is Your Time
“Even if the only available time to work out is the evening, it’s important to keep in mind that not everyone is affected the same way by evening exercise,” Ting says. “Some people may be unaffected, so monitor your own ability to sleep in relation to the time of day that you work out.”
Bianca Spicer, an exercise physiologist and owner of Spicer Fitness in Atlanta, Georgia, agrees that the best time for you to work out is entirely dependent on you as an individual. “The ‘best time’ is when you can fit it into your schedule consistently.” And that consistency is key, because establishing a workout routine will help you stick with exercise and make it part of your everyday lifestyle.
If you’re able to get up early and get your workout in, that’s great because the pressures of the day are less likely to intrude and you can stay consistent with that timetable. However, “if you tend to schedule workouts in the mornings but miss them more often than not, then re-evaluate a later time that doesn’t get interrupted,” Spicer says.
Your own energy levels throughout the day can also dictate what will work best, Spicer says. “Some people have the most energy in the morning and can take on an intense workout while others drag, so the workout isn’t as good.” If you’re not a morning person, “try working out in the afternoon or evening when your brain and body is more alert,” she says.
She also notes that as we age, our optimal workout times can change. For some younger people, an evening workout is fine, but older adults may find it disrupts sleep, and they’re better off getting an early jump on the day. Those shifts are natural and related to how the circadian rhythm changes over time.
And if you’re really crunched for time, consider breaking up a workout into two shorter sessions at two different times. The main point is to get the exercise consistently, however it fits into your life.
[See: Steps to Fall Asleep Fast.]
Tips for Getting Better Sleep After a Workout
“If your only option is to exercise before bed, it may still be beneficial for you overall,” Holfinger says. Still, there are a few things you can do to help your body adjust to evening exercise and get better rest after a workout.
— Establish a routine. “Sleep quality can be influenced by consistency and routine,” Ting explains. So, while working out in the morning or mid-day might be best, if you can develop a regular routine, your body may be able to adjust to evening workouts and you may find that sleep disruptions dissipate over time. “Working out at the same time every day, even if it’s in the evening, along with anything habitual that you do prior to bed — such as reading, which can help your brain establish that it’s time to sleep — can also be helpful.”
— Change the type of exercise you do at night. “Exercises that significantly raise your core body temperature such as a vigorous cardio workout may be more likely to negatively impact sleep than moderate resistance exercises or lighter activities such as yoga,” Ting says. Sweating is a sign that your core body temp is elevated, and as such, “aerobic exercise that produces sweating and lasts longer than 20 minutes is sufficient to impact sleep if it’s completed too close to bedtime.”
— Keep the intensity lower. Spicer recommends keeping your workout intensity “low to moderate” if you’re exercising shortly before bed. This also helps keep your core body temperature lower.
— Keep it shorter. You might also opt to keep your workout a little shorter if you’re exercising just before bed. “The timing of exercise prior to bedtime may be governed by the intensity of exercise — how high you take your body temperature — and the duration — how long you keep your body temperature elevated,” because both of these factors influence how long it will take for your body to cool down after exercise, Fotinakes says. “By the same measure, it’s not a great idea to awaken in the middle of the night to engage in aerobic exercise when the gym is empty because it’s going to impair your ability to return to sleep afterwards.”
— Add a cool-down period. Daly recommends including a “cool down to your workout, such as steady state, low-intensity cardio, stretching, soft tissue work or deep breathing,” at the end of the session to help bring your body to a more relaxed state.
— Wind down with yoga or mediation. “Yoga and meditation post-exercise can also be helpful to calm the mind and body to help facilitate sleep,” Ting says.
— Eat something post-exercise. Daly also recommends having “a meal with carbohydrates” after your workout to induce sleep. And Spicer recommends giving your system some time to digest that meal before lying down. A cup of yogurt with some berries, a banana with peanut butter or hummus with vegetables are all good options that provide protein and carbs for recovery and won’t be too heavy on your stomach before bedtime.
— Avoid caffeine. Caffeine is “a common pre-workout stimulant,” Daly says, but you should try to avoid it for “several hours before bed,” as it’s notorious for disrupting sleep.
— Take a hot shower or bath after exercising. A hot shower or bath following exercise can “facilitate cooling off the body and speeding the drop in core temperature that can help trigger sleep,” Ting says. A warm bath or shower stimulates the body’s temperature regulation system, causing the body to cool itself. That cooling can help you fall asleep faster.
— Experiment with timing. Find the right interval between working out and sleep for your body. Maybe you need an hour. Maybe two or three is optimal. Try out different times and types of workouts to find what feels best.
Lastly, Spicer notes that sleep and exercise are intricately intertwined and you need plenty of both to stay in optimal health. Studies have found that “not enough sleep and sleep disorders are associated with increased risk of chronic disease. Tiredness and low-productivity can lead to poor health choices throughout the day.”
Plus, sleep is when the body repairs itself, which is why you should be looking to get seven to nine hours of it a night on average.
More from U.S. News