Working Out Before Bed: Exercise and Sleep

Working Out Before Bed: Exercise and Sleep

Finding the time to workout can be difficult. We’re all extremely busy. If we’re not working, we’re taking care of the family and household, running errands or sleeping.

If you’re trying to lose weight, getting in daily exercise can prove to be rather tricky. If you’re one of those people who gets their workout in just before bed, you’ve probably heard that doing so can disrupt your sleep pattern and wreak havoc on your sleep quality. But this isn’t necessarily the case.

Exercise and Sleep

Exercise has a dramatic impact on sleep. Generally speaking, regular exercise can help improve sleep quality as well as decrease the amount of time it takes you to fall asleep. In fact, there are a number of studies that suggest regular exercise can help people who suffer with chronic insomnia.

One study suggested that a single session of aerobic moderate-intensity exercise decreased the amount of time it took to fall asleep and lengthened the amount of time asleep when compared to sleep quality on a day without exercise (Passos et al., 2010). But that same study also said that lifting weights or doing vigorous aerobic exercises like running didn’t improve sleep at all.

Other studies have been conducted on the long term effects of exercise and sleep. One study found that after four to 24 weeks of regular exercise, adults with insomnia fell asleep faster and slept better than before they started exercising (Guilleminault et al., 1995; Passos et al., 2011; Reid et al., 2010). The subjects also slept slightly longer than they had in the past.

Exercise may help you fall asleep (and stay asleep) for several reasons:

  1. Exercise increases endorphins and decreases the stress hormone cortisol. Cortisol is the hormone responsible for the fight or flight response. Most people in this day and age have high cortisol levels since we are under stress almost constantly. This is one of the reasons so many people suffer from insomnia. Cortisol keeps our brain on high alert. It’s the reason you remember everything you have to do when your head hits the pillow at night and makes falling asleep very difficult. It also affects sleep quality. Excess cortisol can cause the brain to spend less time in the deeper stages of sleep and in severe cases, the brain may even skip a stage during a cycle.
  2. Exercise can adjust your circadian rhythm. The circadian rhythm is essentially your internal clock. It tells your body when to wake up and when to go to sleep among other things. Exercise can help reset this clock, depending on when you exercise.
  3. Exercise increases your internal temperature. The resulting drop in temperature after exercise can help you fall asleep. This may be the main reason for the effects of exercise on the circadian rhythm.

Exercise Before Bed

Exercise before bed may actually be beneficial for some people. A study conducted by Lack LC. et al 2008   suggests that people with insomnia suffer from thermodisregulation. In other words, their core body temperature may rise at various times during their sleep cycle causing them to wake several times during the night, or they may suffer with a higher internal body temperature throughout the day, which leads to a state of chronic hyperarousal and anxiety.

Exercise before bed can help reset the internal temperature because during exercise your internal temperature rises, which is why you sweat. But after exercising, your internal temperature drops within about an hour. Many people may notice that they feel colder after exercising than they normally would for this reason. Although more research needs to be done in this area, the initial findings are promising.

Personally, I am constantly hot. I’ve been known to sweat in a building that has the thermostat set to 69 or 70 degrees. But after a vigorous workout (and it has to be vigorous) I tend to feel very cold within about 60 to 90 minutes after a workout. For this reason, I have recently made an effort to workout every morning before going to work to prevent myself from sweating throughout the day. Interestingly, I tend to get colder as the day progresses.

Should You Exercise Before Bed?

For most people who have occasional trouble sleeping at night or trouble staying asleep, exercise may help them fall asleep faster and sleep more deeply after just one session of moderate-intensity aerobics, regardless of when the exercise is performed. However, for people with insomnia, the results won’t be as instantaneous.

A study conducted by Kathryn J. Reid, PhD, found that it can take up to four months for patients with insomnia to notice any improvement in their sleep. This means insomniacs need to exercise consistently three to four times a week for at least four months before they will notice any improvement in sleep quality and quantity.

It’s important to remember that sleep is subjective and varies from person to person. What might work for me might not work for you. The key is to listen to your body. For me, exercising in the morning helps me attack my workday in a good mood and without sweating my butt off. It also has improved my sleep quality tremendously. I have tried working out at night, and although I sleep quite well, I don’t get the benefit of the lower core temperature.

Sleep Tracking 2/14/2014


My advice? Try it for two weeks and see what happens. It’s important to be consistent when trying to find the right time to exercise. You may want to keep a sleep journal and record how you feel before going to bed, and upon waking to get a better idea of how you’re sleeping.

You’ll want to keep this diary for at least two weeks prior to changing your current routine in order to quantify the change in your sleep quality when you do alter your routine. You could also keep a simple spreadsheet with sleep times, durations and quality ratings.

Alternatively, you might invest in a fitness tracker such as a Fitbit or Jawbone, which can track your sleep for you if keeping a diary or log seems to tedious. My Fitbit has been indispensable in determining if exercise has made an impact on my sleep quality. If you would like more information on choosing the right fitness tracker for you, check out my Ultimate Guide.

Have you noticed that exercise improves your sleep quality? Tell me about it in the comments below!


Reynolds, Gretchen. How Exercise Can Help Us Sleep Better via NY Times. Aug 2013

How Does Exercise Help Those with Chronic Insomnia via Sleep Foundation

Lack LC, Gradisar M, Van Someren EJ, Wright HR, Lushington K. The Relationship Between Insomnia and Body Temperatures. 2012

Guilleminault C, Clerk A, Black J, Labanowski M, Pelayo R, Claman D. Nondrug treatment trials in psychophysiologic insomnia. Arch Intern Med. 1995;155(8):838-44.

Passos GS, Poyares D, Santana MG, D’Aurea CV, Youngstedt SD, Tufik S, de Mello MT. Effects of moderate aerobic exercise training on chronic primary insomnia. Sleep Med. 2011;12(10):1018-27.

Reid KJ, Baron KG, Lu B, Naylor E, Wolfe L, Zee PC. Aerobic exercise improves self-reported sleep and quality of life in older adults with insomnia. Sleep Med. 2010;11(9):934-40.

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