How Exercise Affects Sleep

Fact-Checked

Written By: Rebecca Levi
Medically Reviewed By: Dr. Sherrie Neustein

 

One third of Americans don’t get enough sleep on a regular basis. It may sound counterintuitive, but exercising is one way to improve sleep. . Let’s explore how exercise affects sleep, and whether it’s a bad idea to exercise before bed.

Can Exercise Help You Sleep?

Yes, most research suggests that exercise can improve  both the length and quality of sleep. Sleep and exercise share a bidirectional relationship. People who sleep well feel more motivated to exercise, and those who exercise tend to enjoy better-quality sleep. However, how exercise impacts sleep quality depends on a person’s age, health, and the intensity and type of exercise they engage in.

For example, older adults seem to enjoy greater benefits to their sleep from exercise. This may be due to the mood-lifting effects of exercise since this population may be more vulnerable to anxiety disrupting their sleep. Exercise also has long-term sleep benefits for people who are overweight.

Aerobic exercise has shown to be particularly impactful for people with insomnia and other sleep disorders. It can improve a person’s total sleep time, ability to sleep through the night, and overall sleep quality. It can also help them fall asleep faster in the first place, leading some researchers to recommend it as a treatment for insomnia.

How Exercise Impacts Sleep

From physical exhaustion to stress relief, a number of factors may contribute to exercise’s effects on sleep.

Exercise Tires the Body

The longer you go without sleep, the more tired you become. Scientists call this the “sleep drive”. Physical activity, including exercise, tires out the body and increases the sleep drive.

Exercise May Lower Anxiety

Pre-sleep anxiety is a common experience for many people with insomnia. Moderate- to high-intensity exercise has been shown to reduce anxiety for several hours. According to one study, a single session of moderate-intensity aerobic exercise significantly reduced the anxiety of people with insomnia. It also cut the time it took them to fall asleep in half, while increasing the amount of time they spent asleep overall.

Among older adults, several forms of exercise appear to help improve sleep, including aerobic exercise, resistance training, yoga, and tai chi. However, one study found that mind-body exercise, like yoga or tai chi, was more effective than the others, and offered additional benefits like improved mood and mental health. Exercising the mind as well as the body may have enabled more restful sleep.

Outdoor Exercise May Reinforce Circadian Rhythms

Exposure to bright light, especially in the morning, can help regulate the body’s internal body clock and promote sleep at night. Some research suggests that exercising outdoors in the morning may help reinforce these natural rhythms. This benefit may be particularly helpful for older adults since circadian rhythms can become weaker with age.

When to Exercise For Better Sleep

What’s the best time of day to exercise? Researchers don’t know for sure. It may depend on the individual, as well as the intensity of exercise.

For example, in a study of people with prehypertension (above-average blood pressure), aerobic exercise in the morning had the best results for sleep, when compared to other times of day. When participants worked out in the morning, it took them significantly less time to fall asleep, and they also woke up less during the night.

Studies of healthy adults have likewise suggested that morning exercise may be better for sleep than evening exercise. One study of young men compared the effects of bike riding in the morning vs. the evening. Those who rode at night had an increased heart rate during sleep, potentially disrupting sleep quality. Exercise energizes the body, increasing heart rate and activating the sympathetic nervous system. Researchers theorized that exercising earlier in the day gives the body enough time to calm down and let the parasympathetic nervous system kick in, allowing one to relax before sleep.

However, this isn’t to say there are no benefits to evening exercise. A study of healthy college-aged people showed that resistance exercise consistently improved their sleep, whether they worked out in the morning, afternoon, or evening. Those who worked out in the morning tended to fall asleep faster, but those who worked out in the evening slept more soundly, waking up less often through the night. In a separate review, regular resistance exercise was shown to improve various sleep measures, including sleep quality, while also relieving anxiety and depression.

Is It Bad to Exercise Before Bed?

Exercise energizes the body, so is it risky to exercise right before going to bed? Again, it depends. Earlier in the day is generally recommended, especially if engaging in moderate or vigorous exercise.

In particular, high-intensity exercise has been shown to increase heart rate and make it harder to fall asleep. In one study, a group of physically fit men performed either a moderate- or high-intensity workout before going to bed. Those who did the high-intensity workout had a higher heart rate and took 14 more minutes to fall asleep.

However, some studies have shown just the opposite: that intense exercise may help people sleep more deeply. When a group of physically active adults exercised 90 minutes before bed, those who felt they had worked out harder had more restorative deep sleep than those who felt they had worked out less. They also fell asleep faster, woke up less during the night, and spent less time awake in bed.

How to Optimize Exercise for Better Sleep

The great thing about exercise is that once you start, research shows you’ll notice the positive effects on your sleep rather quickly. As exercise becomes part of a regular routine, it still benefits sleep, although the research is unclear on to what extent. Some studies find that regular exercise only produces modest benefits, while others find it continues to have a significant, positive impact on the time it takes to fall asleep, how long one sleeps, and overall sleep quality.

While exercise's impact on sleep varies from person to person, there’s always an opportunity to squeeze a bit more value from each workout. To do that, follow these tips.

Try Exercising Outside in the Morning

It’s time to give your snooze button a break. Instead, wake up and try exercising outside. Since both early morning sunlight and physical activity can positively affect sleep, some researchers recommend pairing the two. Particularly for vigorous outdoor exercise, a morning workout has a better impact on sleep than an afternoon one.

Avoid Vigorous Exercise at Night

It’s okay to exercise at night instead, but it’s better to reserve lower- to moderate-intensity workouts for this time, like walking, yoga, or a leisurely bike ride. Studies have shown that vigorous exercise wakes the body up and makes it harder to fall asleep. Experts recommended leaving enough time, at least one hour, between the end of a workout and bedtime to allow the body to wind down.

Keep a Sleep Diary

If you’re unsure whether a morning or evening workout routine is best for you, track your results with a sleep diary. Note when you exercise, when you go to bed, and when you wake up. Also,note what type of exercise you did and how well you slept. Over time, see if you notice any patterns. Once you figure out a time that works, be consistent. Habits make it easier to stick with a new workout routine.

Practice Good Sleep Hygiene

Sleep hygiene includes things like limiting caffeine and alcohol, following a regular sleep schedule, and exercising frequently. A regular aerobic exercise routine, paired with good sleep hygiene, was shown to improve sleep quality and mood for a group of older adults — even increasing their total sleep time by an average of over one hour per night.

For help finding an appropriate workout routine for your health goals, talk to your doctor.

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