Exercise can improve sleep.
January 02, 2015
By Dr. Mercola
It is important to make time for exercise on a regular basis, and for many this means squeezing in a workout early in the morning, during a lunch hour, or even late at night, just before bed.
However, some have difficulty sleeping if they exercise too late in the evening. If you are one of these individuals, you might be reacting to the increased adrenalin and cortisol that result from strenuous activity, which can make it difficult to fall asleep.
A common recommendation is to avoid intensely exercising within three hours of bedtime so you have adequate time to wind down.
Research suggests, however, that many people will sleep better if they exercise—even if that exercise is done in the evening, as late as an hour or two before bed. If your lifestyle is such that you can only exercise at night, then there are ways to improve your chances of sleeping well.
After all, exercising at night is preferable to abandoning your exercise routine altogether and losing all of those important health benefits. Sleep and exercise are equally important for your health, so the trick is to develop a routine that optimizes both.
Survey Says: Vast Majority Sleep Better After Exercise
A few recent studies suggest that fewer people are troubled by post-workout insomnia that previously thought. In 2013, a poll by the National Sleep Foundation1 found that 83 percent of people report sleeping better when they exercise than when they don’t, even if the exercise is late at night.
More than half of those who exercised moderately or vigorously said they slept better on workout days than non-workout days, and just three percent of late-day exercisers said their sleep quality was worse when they exercised than when they did not. The National Sleep Foundation concluded:
"While some believe exercising near bedtime can adversely affect sleep and sleep quality, no major differences were found between the data for individuals who say they have done vigorous and/or moderate activity within four hours of bedtime compared to their counterparts (those who did vigorous or moderate activity more than four hours before bedtime).
According to the 2013 Sleep in America® poll, the conclusion can be drawn that exercise, or physical activity in general, is generally good for sleep, regardless of the time of day the activity is performed."
Vigorous Evening Activity Often Improves Sleep
Two other studies have confirmed that vigorous evening exercise may improve sleep, as opposed to disturbing it. One study2 followed 52 19-year-old students who played sports for up to 90 minutes in the evenings, ending about 1.5 hours before their usual bedtime.
Those who reported more exertion during the sports fell asleep faster, woke up fewer times during the night, and slept more deeply than those who exercised more moderately.
The students who exercised with higher levels of exertion also reported increased tiredness, less hunger, and better moods at night. The researchers concluded:3
“Against expectations and general recommendations for sleep hygiene, high self-perceived exercise exertion before bedtime was associated with better sleep patterns in a sample of healthy young adults.”
Another study4 published in 2011 found that people who exercised vigorously for 35 minutes right before bed slept just as well as on nights when they didn't exercise.
The point is that it appears the cautions about exercising in the evening may be a bit overstated, and the only way to know how it affects YOU is to test it out.
If you’ve been avoiding evening exercise out of fear of insomnia, then it would be instructive to test out the theory—you might be pleasantly surprised. But if your experiment is an epic failure, then you may need to try a few tricks to help your body gear down more quickly so you can sleep.
Overdosing on Exercise Can Backfire
One of the major causes of insomnia is overexercising. Exercising excessively or incorrectly can backfire on your health in multiple ways, including interfering with your sleep.5 Overexercising can actually cause your tissues to break down, become inflamed, and fail to heal or repair, which raises your risk for injury. This is why it’s so important to make sure you allow your body to fully recover between sessions. Excessive endurance exercise activates your stress response, elevating your stress hormones—cortisol, adrenaline, and norepinephrine. If these hormones stay elevated all of the time, it’s not good for your heart, fitness, or overall health.
Stress hormones increase your heart rate, alertness, and the blood flow to your muscles, so they help you perform the physical activity but may make it difficult to doze off.6 Cortisol plays an important role in your sleep-wake cycles. Normally, your cortisol level peaks about 30 minutes after you wake up and then declines throughout the day, being lowest at bedtime, which helps you fall asleep. But doing something like, say, an evening spinning class may throw your system off by kicking your cortisol level back up again.
Over time, extreme exercise may give you chronically elevated stress hormone levels, which can weaken your immune system and raise your risk for chronic disease. The most serious risk of extreme endurance training involves damage to your heart—including sudden cardiac death. This is especially true if you have a history of heart disease.
Tips for Preventing Post-Workout Insomnia
If evening is the most convenient time of day for you to exercise and it doesn’t interfere with your sleep, then by all means continue. But if you are one of the folks who has a hard time nodding off after an evening workout, then you might want to change up your routine.
Sometimes selecting a less strenuous workout at night may be helpful, while saving the heavy hitting, such as high-intensity interval training (HIIT), for morning or afternoon. Consider reserving your evening exercise sessions for less strenuous exercises like yoga,7 Pilates, or even an evening walk. Or just try lowering the intensity of what you’re already doing. Restorative Yoga is particularly beneficial for stress reduction, relaxation and sleep.8 Below are five more tips to help you slip into slumberland with ease: 9, 10
- If possible, seek to get your workout done three to four hours prior to bedtime
- Coffee before a workout can enhance your fitness gains, but if you exercise in the late afternoon or evening, the caffeine may keep you awake
- Staying well hydrated during your workout can help blunt your cortisol response
- Try taking a hot bath, shower, or sauna just before bed. The sudden temperature drop from getting out of the bath helps your body shut itself down, facilitating sleep
Whatever you do in terms of exercise, you should never allow yourself to become sleep deprived—the price for doing so can be steep. Sleep deprivation has the same effect on your immune system as physical stress or illness, which helps explain why poor-quality or insufficient sleep is tied to an increased risk of numerous chronic diseases. Research tells us that inadequate sleep can contribute to everything from physical aches and pains to diabetes, heart disease, and even irreversible brain damage.
The US Centers for Disease Control and Prevention (CDC) actually classifies insufficient sleep as a public health epidemic, as it’s crucial for virtually every tissue and organ in your body. It’s during sleep that metabolic waste products are eliminated from your brain, and it’s thought that insufficient sleep may actually injure your brain cells, impacting your cognition.11 Recent studies show just how dangerous sleep deprivation really is. The following are just a few of the more recent studies on this topic:
- People who reported sleeping less each night were found to have swelling in a region of their brain that is predictive of more rapid cognitive decline.12
- Older men who sleep poorly are more likely to face subsequent cognitive decline.13
- Older adults who sleep less than six hours or more than eight hours per night, on average, have lower brain function scores.14
- People with chronic sleep problems may develop Alzheimer's disease sooner than those who sleep well.15
- Interrupted sleep may be as harmful as no sleep at all—just one night of interrupted sleep was found to be enough to wreak havoc on mood and energy levels.16
If you have insomnia, it may take some time before you notice any benefits from exercise. A study17 from Northwestern University found that working out once is not enough to improve sleep—you have to sustain your fitness routine for a number of weeks to months. Sleep science also makes it clear that you can’t "catch up" on sleep over the weekend—that is, it doesn’t prevent the damage. So you must take steps to ensure that you sleep well every night.
To determine whether or not you’re getting enough sleep, assess the quality of your waking day. If your energy is steady and rhythmic through the day, you’re probably getting plenty of good quality sleep. Make sure you’re going to bed early enough, and that your bedroom is dark, quiet, cool, and free of electromagnetic currents. For an extensive list of tips for improving your sleep, please refer to this previous article.
Additionally there is an explosion of fitness trackers coming that can easily help you monitor not only how much you sleep but the quality and tell you how much deep sleep you are getting.
Consider Exercising in the Morning
There is research suggesting that morning or afternoon exercise may offer unique health benefits, but if you're not sure which time of day you prefer, just do some experimenting. Personally, I prefer exercising in the morning for a number of reasons—the first being that my workout is completed early on, leaving less chance for other obligations to eat up my exercise time. Additionally, exercising in the morning makes it easy to exercise while fasting, which amplifies its benefits.
Another reason to workout first thing in the morning is that it may actually help squelch food cravings. Research shows that 45 minutes of moderate-to-vigorous exercise in the morning reduces food cravings, both immediately and throughout the day.18 Morning exercise may also help you keep moving even after your workout, which is key to optimal health. So if you can, give morning workouts a try. If not, don’t stress… fit your workouts in when they’re most convenient for you. It’s always best to listen to your body and honor what it tells you. The best time for you to exercise is whenever you will do it consistently.
