Lifestyle
Lifestyle

How Exercise Affects Sleep

By Lana Adler

Updated March 24, 2021

 

Exercise improves your health, your mood, and even your sleep. In fact, some researchers have gone so far as to name exercise as the daytime behavior (1) most associated with better sleep. The relationship between exercise and sleep is a reciprocal one (2). It’s easier to sleep when you’ve exercised, and it’s easier to work out after a good night’s sleep.

How Does Exercise Affect Sleep?

Exercise improves sleep quality (3). It increases the overall amount of time (4)  you spend asleep, as well as the amount of time you spend in slow-wave sleep (5), specifically. Also known as deep sleep, slow-wave sleep is the most restorative (6) stage of sleep. Human growth hormone is released (7), your heart rate and breathing slow down, and your body physically repairs itself.

While exercise improves sleep quality and duration for all ages, its effects can vary depending on your age and overall health. For example, older adults who take up a regular exercise routine enjoy better sleep efficiency (meaning they spend more of their time in bed asleep, as opposed to tossing and turning). Among adolescents, a 12-week exercise program increased the amount of time they spend in rapid eye movement (REM) sleep, a stage of sleep tied to cognitive performance.

Does Exercise Help You Sleep?

Perhaps the most obvious way exercise helps you sleep is that it physically tires you out. Physical activity increases your sleep drive (8), or need for sleep. When you’ve exercised, your body wants to recover, and sleep is a good way of doing that.

Exercise also provides significant stress relief, which is strongly associated (9) with sleep troubles. Nearly half (10) of adults say stressful thoughts keep them lying awake at night. When you exercise, your brain releases endorphins (11). These chemicals give you that post-exercise high, boosting your mood while reducing stress.

Aerobic exercise in particular can be effective for relieving sleep issues, and is recommended as a drug-free treatment for insomnia and other sleep disorders. In a study of individuals with obstructive sleep apnea, a 12-week program of moderate-intensity aerobic exercise and resistance training reduced the severity of their symptoms by 25%. Regular exercise has also been shown to relieve other symptoms of insomnia and sleep apnea, such as daytime sleepiness, fatigue, and depression.

Can Sleep Help You Exercise?

In a word, yes. People who experience restless or insufficient sleep tend to be less active than their well-rested peers. People with sleep disorders, like insomnia or sleep apnea, also tend to be less physically active than those who sleep well. This may be due to the fact that the symptoms of these sleep disorders — including fatigue, daytime sleepiness, and low energy — make it challenging to feel motivated to work out.

Bad sleep is also a predictor for low activity levels, in both the near-term and well into the future. Just one night of poor sleep can lead people to cut their workouts short the following day. Further, long-term studies show that people who experience poor sleep become less physically active two to seven years later.

On the flip side, when you sleep better, your workout routine reaps the benefits. Athletes who get more sleep enjoy improved performance (12), and they have a lower risk of injury and illness. When the Stanford University men’s basketball team improved their sleep quality, their sprint times and shooting accuracy both improved (13). They shaved about a half-second off their sprints, and increased their free throw and three-pointer percentages by 9%.

When Should I Exercise for Better Sleep?

The best time of day for exercise depends on the individual . Historically, experts cautioned against exercising at night (14). Exercising is an energizing activity that raises your core body temperature, which is the opposite of what happens before sleep. Your body temperature naturally lowers in the evening (15) about two hours before bed, signaling to your brain that it’s time to fall asleep.

However, the increase in body temperature and energizing effects of exercise may wear off in 60 to 90 minutes (16). More recent research has found that as long as you complete your workout at least that long before bedtime, it may not interfere with your ability to sleep. Studies show that low- to moderate-intensity exercise, such as yoga or walking, can be performed at night with no impact on sleep.

When it comes to high-intensity workouts, like running or heavy weightlifting, things get a bit less predictable. Some people can fall asleep without a problem (17), while others may take a bit longer and find themselves waking up during the night. Vigorous exercise may be more effective in boosting sleep if it’s performed earlier in the day — giving your body plenty of time to cool back down.

Some studies have found that people who exercise in the morning fall asleep faster, while those who work out at night take longer. There is also evidence that those who wake up and work out earlier tend to be more physically active than their night-owl peers. If you’d like to switch from night owl to early bird, or vice versa, you’ll be happy to hear that exercise can help shift your circadian rhythms, or sleep-wake cycle. For example, night owls can shift the circadian cycle forward by working out in the morning.

To find the best workout time for you, try keeping an exercise diary for a couple weeks. Note when you exercised, the type of exercise you did, how long it took you to fall asleep, and whether your sleep was restful. Adjust the time of day you exercise, and you’ll be able to see whether morning or late-night exercise is a better choice for you.

How Much Should You Exercise for Better Sleep?

Some studies have found that just one 30-minute workout of moderate-intensity aerobic exercise can improve sleep that very night. Other studies have found that it takes longer for the effects of exercise to positively impact sleep.

The important thing, perhaps more than the intensity of your workout or how long you do it, is to commit to exercising regularly. Just 30 minutes of low-intensity exercise, like walking, or household chores, can improve your sleep and reduce your risk of death by 17% (18). Even if you can’t get a full 30 minutes in all at once, the research shows that splitting your exercise up into shorter periods, from 1 to 5 minutes, can still be beneficial.

If you want better sleep, exercise is always a good idea. Regular exercise can help you fall asleep faster, sleep longer, and enjoy other benefits like better mental, physical, and overall health (19).

 

References

 

  1. https://pubmed.ncbi.nlm.nih.gov/15892929/ Accessed on March 19, 2021.
  2. https://www.ncbi.nlm.nih.gov/pubmed/25729341 Accessed on March 19, 2021.
  3. https://pubmed.ncbi.nlm.nih.gov/30018855/ Accessed on March 19, 2021.
  4. https://pubmed.ncbi.nlm.nih.gov/28458924/ Accessed on March 19, 2021.
  5. https://pubmed.ncbi.nlm.nih.gov/12531177/ Accessed on March 19, 2021.
  6. https://pubmed.ncbi.nlm.nih.gov/19998869/ Accessed on March 19, 2021.
  7. https://pubmed.ncbi.nlm.nih.gov/8627466/ Accessed on March 19, 2021.
  8. https://www.cdc.gov/niosh/work-hour-training-for-nurses/longhours/mod2/11.html Accessed on March 19, 2021.
  9. https://pubmed.ncbi.nlm.nih.gov/17937582/ Accessed on March 19, 2021.
  10.  https://www.apa.org/monitor/2017/12/numbers Accessed on March 19, 2021.
  11. https://pubmed.ncbi.nlm.nih.gov/6091217/ Accessed on March 19, 2021.
  12. https://pubmed.ncbi.nlm.nih.gov/29135639/ Accessed on March 19, 2021.
  13. https://pubmed.ncbi.nlm.nih.gov/21731144/ Accessed on March 19, 2021.
  14. https://pubmed.ncbi.nlm.nih.gov/30374942/ Accessed on March 19, 2021.
  15. https://pubmed.ncbi.nlm.nih.gov/31105512/ Accessed on March 19, 2021.
  16. https://pubmed.ncbi.nlm.nih.gov/31072217/ Accessed on March 19, 2021.
  17. https://pubmed.ncbi.nlm.nih.gov/20673290/ Accessed on March 19, 2021.
  18. https://pubmed.ncbi.nlm.nih.gov/30551177/ Accessed on March 19, 2021.
  19. https://medlineplus.gov/benefitsofexercise.html Accessed on March 19, 2021.