Series By: Zachary Zenko & Jamie Foehl
Exercise has been called a “polypill” (3) because of its plethora of benefits. This will be the first in a series of blog posts designed to review some of the many benefits of exercise in an accessible manner. This first post is about exercise and sleep. Upcoming posts will be about exercise and depression, anxiety, addiction, pain, and fatigue. Some academic research will be reviewed, synthesized, and summarized so that people without a background in research methods and statistics can appreciate the findings. The evidence in these posts is by no means comprehensive. Instead, only a glimpse at the available evidence is shared.
Exercising Your Way to a Good Night’s Sleep
Sleep is a wonderful activity that we all enjoy, yet few of us seem to get enough sleep each night. Even when we’re tucked in and turn off the lights, things like daily stresses, life’s concerns, and our phones are competing for our limited sleep time. And then there’s snoring. Almost half of us do it! On average, it takes about twenty minutes to fall asleep. More than one out of four adults in the USA feel unrested and do not get enough sleep(6). Thankfully there is something we can all do that is expected to result in better sleep: Get more physical activity.
What follows is a review of some of the academic research around exercise and sleep. The evidence in this post is by no means comprehensive. Rather, it’s a glimpse into the available evidence, most of which points in the direction of showing that you just might be able to exercise your way to a good night’s sleep.
So, how much sleep is enough sleep, anyway?
Buxton and Marcelli (2) analyzed national data and found that sleeping too little (less than seven hours per night) and sleeping too much (more than eight hours a night) is associated with a variety of health issues, such as diabetes, obesity and cardiovascular disease (this was after controlling for variables such as age, ethnicity, education and family environment).
We cannot be sure if insufficient or excess sleep came before or after health issues. In other words, we do not know if those sleep issues were caused by insufficient or excessive sleep, or if they caused insufficient or excessive sleep. Still, this research had several strengths worth noticing, including the very large, nationally representative sample.
OK, so what about exercise and sleep?
Several researchers have investigated the link between exercise and sleep. In one survey, researchers found that morning exercise is associated with better sleep quality (1). Again, however, these data do not allow us to conclude that exercise causes better sleep. It may be possible that people with better sleep quality are able to exercise more, for example. A true-experimental design or randomized controlled trial would allow researchers to conclude that exercise caused better sleep.
Fortunately, there are randomized controlled trials (RCTs) involving adults with sleep problems (the fortunate part is the RCT, not the sleep problem!). A systematic review of six RCTs from 2012 (7) concluded that exercise leads to moderate improvements in sleep quality and sleep latency. In other words, its takes less time for exercisers to fall asleep and they report better sleep.
King and colleagues (5) performed one of the studies in the review. The authors studied older adults (in this case, older is 55+) who were not meeting the minimum recommended amounts of physical activity and had sleep complaints. Participants in the exercise group were asked to attend two exercise classes per week and exercise on their own on three additional days per week. Participants were asked to exercise for at least 30 minutes on their own, and the exercise classes included 35-45 minutes of moderate-intensity exercise. Participants in the health education control group were asked to attend weekly educational sessions that were 90 minutes each. After 12 months, people in the exercise group spent more time in stage two sleep (deeper sleep) and less time in stage one sleep. Exercisers had fewer sleep disturbances, felt more rested, and reported falling asleep faster.
Because sleep is something we all do, it might be tempting for people to think we understand a lot about sleep. We have theories about sleep based on our own experience. For example, some people contend that exercising too close to bedtime can interfere with sleep. However, research suggests that this is not the case (1) and that exercising before bedtime might actually improve sleep in people who already sleep well (4).
Taken together, the evidence suggests that physical activity can help us get to sleep faster and feel more rested, particularly if we’re having sleep problems in the first place (which many of us are). We’re not talking about a marathon before bedtime but rather thirty minutes of moderate-intensity physical activity – like a brisk walk around the neighborhood, or housework. Choose an activity that you enjoy. Before you count sheep, give it a try. If nothing else, you’ll wake up in a tidier house and you’ll be heathier in other ways.
- Buman MP, Phillips BA, Youngstedt SD, Kline CE, Hirshkowitz M. Does nighttime exercise really disturb sleep? Results from the 2013 National Sleep Foundation Sleep in America Poll. Sleep Med 2014;15(7):755–61.
- Buxton OM, Marcelli E. Short and long sleep are positively associated with obesity, diabetes, hypertension, and cardiovascular disease among adults in the United States. Soc Sci Med 2010;71(5):1027–36.
- Fiuza-Luces C, Garatachea N, Berger NA, Lucia A. Exercise is the real polypill. Physiology 2013;28(5):330–58.
- Flausino NH, Da Silva Prado JM, de Queiroz SS, Tufik S, de Mello MT. Physical exercise performed before bedtime improves the sleep pattern of healthy young good sleepers. Psychophysiology 2012;49(2):186–92.
- King AC, Pruitt LA, Woo S, et al. Effects of moderate-intensity exercise on polysomnographic and subjective sleep quality in older adults with mild to moderate sleep complaints. J Gerontol A Biol Sci Med Sci 2008;63(9):997–1004.
- Ram S, Seirawan H, Kumar SKS, Clark GT. Prevalence and impact of sleep disorders and sleep habits in the United States. Sleep Breath 2010;14(1):63–70.
- Yang P-Y, Ho K-H, Chen H-C, Chien M-Y. Exercise training improves sleep quality in middle-aged and older adults with sleep problems: A systematic review. J Physiother 2012;58(3):157–63.
Zachary Zenko is a postdoctoral associate at the Center for Advanced Hindsight. He has a PhD in Kinesiology from Iowa State University and a background in exercise science with research focuses in exercise psychology. Broadly, his research is aimed at promoting physical activity and exercise behavior by creating positive associations with exercise, making exercise experiences more pleasant, and using behavioral economics. He is also interested in the psychological predictors and consequences of exercise. Zachary can be reached at firstname.lastname@example.org and @zackzenko on Twitter.
Jamie Foehl is a Senior Applied Researcher at the Center for Advanced Hindsight. Jamie can be reached at Jamie.email@example.com and @jamiefoehl on Twitter.
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