Regular exercise and high-quality sleep are both critical for long-term health. Sadly, most people don’t get enough exercise OR sleep. Plus, a significant percentage of the population suffers from sleep problems that make it difficult to fall asleep or stay asleep once they do. In any 12-month period, 20 to 40% of adults experience insomnia and, for some, it’s a chronic problem that keeps them awake night after night.
But, there’s good news. Studies suggest that exercise improves the symptoms of a variety of mental and physical health issues. Therefore, you might wonder what impact exercise has on insomnia. Can working out regularly help you sleep better – and does it matter what time of the day you exercise if you want a good night’s sleep?
Exercise and Sleep: Does Exercising Too Close to Bedtime Cause Insomnia?
When you do a relatively intense workout, it powers up your sympathetic nervous, the fight-or-flight division. In response, your heart rate rises to meet the extra oxygen demand that exercise imposes and you feel more energized and alert. Plus, exercise raises your core body temperature. Ramping up your sympathetic nervous system is beneficial early in the day when you need energy to power through a busy work day – but what if you work out in the late afternoon or evening? In the past, researchers have questioned whether exercising later in the day interferes with sleep due to the activating effects it has on your body. Surprisingly, most studies show that exercise doesn’t worsen insomnia and may even improve sleep quality.
What does science show? The majority of studies suggest that exercise has a beneficial effect on sleep quality. In one study published in the journal Psychophysiology, participants who performed moderate-intensity aerobic exercise at 8:00 P.M. slept better when they turned in a few hours later. Yet another study used polysomnographic and acrigraphic studies (a way of monitoring human rest/activity cycles). The participants were also closely monitored in a sleep lab. The results showed that exercising in the evening did not negatively impact sleep quality, although resting heart rate was higher on days that the participants exercised and during the first three hours of sleep. So, exercise does, indeed, boost the activity of the sympathetic nervous system and the effects last even after you turn in for the night. However, it doesn’t seem to make it harder to sleep, based on this study.
Other studies show that low-intensity exercise prior to sleep may enhance sleep. That’s not surprising since low-intensity exercise helps relieve stress and it doesn’t significantly increase body temperature or over-activate the sympathetic nervous system. Yet, exercise at all intensities seems to improve sleep quality. One study that surveyed 2,600 healthy women and men of all ages found that getting at least 150 minutes of moderate to intense exercise weekly was linked with a 65% improvement in sleep quality.
Another study found that meeting the recommended exercise guidelines was associated with feeling less sleepy throughout the day. There were other perks as well. The same study showed that regular physical activity reduced the incidence of leg cramps by 65%. If you’ve ever had one of those, you know how painful they are.
Long-term Impact of Exercise on Sleep Quality
At least short-term, there’s no strong evidence that exercising, even later in the day, makes it harder to sleep. In fact, it may improve sleep quality. Longer term, physical activity can benefit subsets of people who suffer from insomnia in another way. A certain percentage of people who have difficulty sleeping and wake up frequently during the night have sleep apnea, a condition where a person stops breathing for periods of time during sleep. Around 25% of men and 12% of women suffer from this condition.
The strongest risk factor for sleep apnea is obesity. By contributing to weight loss, exercise may help sleep apnea sufferers reverse their condition through weight loss as well as reduce the risk of developing sleep apnea in people who don’t have it already. In fact, a study published in the journal Lung found that supervised exercised improved sleep quality in people with sleep apnea. The participants also experienced less daytime sleepiness. If you have problems sleeping, see a health care professional to make sure sleep apnea isn’t the cause. Sleep apnea is associated with a variety of complications and needs treatment.
All in all, studies show that exercise improves sleep quality, as measured subjectively, as well as when participants with insomnia are observed in a sleep lab. So, exercise really can help you get a better night’s sleep.
Is There a Best Time of Day to Exercise to Improve Sleep?
These studies should help bust the myth that exercising in the late afternoon and evening interferes with sleep. There’s no strong evidence that it does. However, one advantage to exercising in the morning is you’re more likely to do it if you get it done first thing. Plus, exercise raises your core body temperature, stimulates your nervous system, and gets you ready to tackle the busy day ahead. When considering when to exercise, how it will impact sleep doesn’t seem to be a major concern. The act of exercising, regardless of time of day, should help you sleep better. From what we know about sleep and how it impacts health, getting a good night’s sleep should always be a priority.
The Bottom Line
Exercise AND sleep, along with diet and stress management, are four pillars of good health. Make sure you’re getting all of them right. As you can see, each affects the other – exercise relieves stress and helps with sleep while it also helps keep your appetite under control. So, keep things balanced – exercise hard and sleep well.
Sleep Med. “Insomnia Statistics”
J Sleep Res. 2011 Mar;20(1 Pt 2):146-53. doi: 10.1111/j.1365-2869.2010.00874.x.
National Sleep Foundation. “Physical Activity Impacts Overall Quality of Sleep”
Up-to-Date. “Overview of obstructive sleep apnea in adults”
Lung. 2014 Feb; 192(1): 175–184. doi: 10.1007/s00408-013-9511-3.
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