Can Too Little Sleep Spoil Your Workout?

Anyone can start a new workout regimen, but here’s a secret than can help you stick to your plan: Get plenty of sleep. You’ve probably heard that regular exercise improves sleep. But experts also say that getting too little slumber can lead to less time spent huffing and puffing the next day, if you can drag yourself off the sofa at all.

Meanwhile, sound sleep habits also appear to aid other fitness goals, like losing weight. Good sleep can protect you from a long list of common health threats. So if you’ve resolved to get healthier this year, a good night’s rest is critical.

Sound Sleep: A Disease Fighter

Adults should get between 7 and 9 hours of sleep each day. Yet about one quarter of men and women in the United States say they struggle to get enough shut-eye. Scientist once thought poor sleep was a symptom of disease, but over the last generation mounting research has linked failure to get adequate rest to an increased risk for many serious diseases, including:

  • Type 2 diabetes
  • Heart disease
  • High blood pressure
  • Frequent infections
  • Obesity

Poor sleep is also linked to  depression and other mood disorders. It isn’t hard to imagine why feeling sad or anxious can keep you up at night, but now scientists believe that not getting enough sleep creates a vicious cycle, worsening mood disorders.

Skipping Workouts

Let’s face it: Tossing and turning all night can make it a struggle to hit the pavement for a long walk or run. “When people get too little sleep, they might feel fatigued and sleepy the next day, so they might not be as motivated to exercise,” says Joseph Cheung, MD, a sleep medicine specialist at the Mayo Clinic in Jacksonville, FL. Cheung frequently prescribes regular exercise to patients with insomnia. But, he explains, the link between sleep and exercise goes both ways. Poor sleep can interfere with your will to work out.

Cheung co-authored a 2017 study published in the journal Sleep Health that shows the two-way relationship between sleep and exercise. In the study, more than 10,000 older women agreed to wear an accelerometer, a device that measures activity level, for a week. They also kept track of how much time they spent in bed. The study found that women who reported getting less than 7 hours of sleep a night spent the most time sedentary, or seated, the following day, and performed relatively little moderate-to-vigorous exercise.  Meanwhile, those who had the highest levels of physical activity (at least 20 minutes of moderate-to-vigorous movement) on a given day were most likely to get between 7 to 9 hours of sleep that night.

In another study, researchers robbed people of sleep to see how that affected their physical activity the next day. They let 18 people sleep up to 8.5 hours a night and exercise as they wished for 2 weeks. Then, for another 2 weeks, all participants were roused from bed after just 5.5 hours of sleep. During that phase, participants spent 24% less time exercising and, on average, an additional 21 minutes a day sitting around.

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Too Little Sleep, Too Many Calories

If you’re trying to lose weight, counting sheep at night will only add to the struggle. “There’s pretty consistent evidence that restricting sleep will lead to greater caloric intake,” says exercise science researcher Christopher Kline, PhD, of the University of Pittsburgh, who studies the relationship between exercise and sleep. “And it’s not calories from celery and carrots. It’s pizza, it’s doughnuts -- sweet and salty foods that are dense in calories.” In other words, junk food that will torpedo efforts to drop a dress size or lose some belly flab.

In a 2020 study published in the International Journal of Obesity, Kline evaluated the “sleep health” of 125 overweight or obese people who were in a weight loss program, measuring how many hours they slept at night, whether they felt alert during the day, were generally satisfied with their sleep, and other things.

“We found that people who had better sleep health were able to lose more weight than people with poorer sleep health,” Kline says. For every one of six healthy-sleep components that a participant possessed at the start of the study, he or she lost an additional 1% of body weight over the next half year. Many of the people who got too little high-quality sleep had obstructive sleep apnea (OSA), which causes snoring and frequent waking. But some people who didn’t have OSA still had poor sleep health, which seemed to interfere with their attempts to shed pounds.

Keys to Better Sleep

In addition to steps such as cutting down on caffeine and alcohol, the following can improve your overall sleep health.

Exercise regularly. And don’t necessarily believe the old advice about avoiding workouts right before bedtime. Research suggests it improves slumber for normal sleepers, Kline says. But if you have insomnia, it might be best to exercise earlier in the day.

Manage your light exposure. Getting some sunlight by day and keeping lights dim in the evening helps promote sleep. The evidence that using electronic devices in the evening disturbs sleep is actually fairly modest, Kline says, though it probably makes sense to limit screen time just before bed.

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Get up at the same time every day, including weekends. But if you have problems falling asleep, don’t go to bed at a set time unless you think you’ll fall asleep. “If you have insomnia, a preoccupation with bedtime can actually lead to not being able to fall asleep,” Kline says. “So if you have problems falling asleep, go to bed when you’re sleepy.” If you don’t have problems falling asleep, keeping a stable bedtime is probably a good idea.

Create a good sleep environment. Keep your bedroom cool, use a white-noise machine if your neighborhood is noisy, hang light-blocking curtains, and get rid of that lumpy old mattress. 

If these things don’t help, get checked by a sleep specialist. They may find that you have OSA, a common condition in which your breathing constantly stops and starts all night. You may need a continuous positive airway pressure (CPAP) machine to help you breathe -- and sleep -- better. Milder cases of this common sleep disorder can also be managed with specially designed mouthpieces.

About 10% to 15% of adults have chronic insomnia. Many can benefit from cognitive behavioral therapy for insomnia (CBT-I), Cheung says. In this type of treatment, a doctor or psychologist with proper training helps you change sleep behaviors with a combination of psychotherapy, relaxation techniques, and other strategies. “CBT-I promotes sleep and reduces sleep anxiety,” Cheung says. If CBT-I doesn’t help, many different types of medications are available for hard-to-treat cases of insomnia.

WebMD Feature

Sources

SOURCES:

Joseph Y. Cheung, MD, sleep medicine specialist, department of pulmonary medicine, Mayo Clinic, Jacksonville, FL.

Christopher Kline, PhD, researcher, School of Education, University of Pittsburgh.

Sleep Foundation.org: “The Link Between a Lack of Sleep and Type 2 Diabetes,” “National Sleep Foundation Recommends New Sleep Times,” “Mental Health and Sleep,” “Sleep Hygiene.” 

Office of Disease Prevention and Health Promotion: “Sleep Health.”

CDC: “Sleep and Chronic Disease.”

Sleep Health: “Bi-directional associations of accelerometer-determined sedentary behavior and physical activity with reported time-in-bed: Women’s Health Study.”

Sleep: “Sleep Restriction Decreases the Physical Activity of Adults at Risk for Type 2 Diabetes.”

National Heart, Lung, and Blood Institute: “CPAP.”

American Journal of Managed Care: “The Epidemiology and Diagnosis of Insomnia.”

© 2020 WebMD, LLC. All rights reserved.

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