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Sleep and Physical Health

Reviewed by Psychology Today Staff

It’s no exaggeration to say that sleep is among the most powerful tools humans have at their disposal to improve their physical health. During sleep, the body undergoes critical repair processes that help fight illness, heal wounds, and recover from the stresses of day-to-day life. Adequate amounts of restful sleep have been convincingly tied to a healthier body (both inside and out), a better immune response, and a longer life.

But sleep deprivation, unfortunately, is all too common—particularly in the U.S.—and may be at least partially to blame for many maladies that are common today. Prioritizing sleep isn’t always easy, but it may help people, on both the individual and societal levels, boost their health and potentially reduce their healthcare costs.

The Powerful Positive Effects of Sleep
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Most people are well-aware of how much better they feel, both mentally and physically, after a night of great sleep. But good sleep does much more than providing the brain and body with a boost of energy. It actually repairs them on a cellular level, addressing damage accumulated over the course of daily life and strengthening key systems that help the body fight disease, improve fitness, and look and feel healthier. Sleep has a beneficial effect on almost all of the body’s major systems—from the cardiovascular system to the muscular system to the digestive system—and could be key to fighting many of the “diseases of civilization” that wreak havoc in the modern world.

Does sleep affect heart health?

Yes, evidence suggests that adequate amounts of restful sleep are good for the heart. Both sleeping too little and sleeping too much have been linked in large studies to an increased risk of cardiovascular disease, heart attacks, and increased blood pressure. Consistent nightly sleep, on the other hand, has been associated with a decreased risk of heart problems; napping during the day may also provide some benefit. Though the exact reason isn’t fully understood, researchers speculate that time spent asleep is less stressful for the heart than time spent awake, and may lower levels of cortisol that can contribute to heart problems.

Can sleep boost your immunity?

There’s a reason that those who are sick are advised to get plenty of rest: A substantial body of evidence finds that sleep helps the body fight infections and boosts general immunity. During sleep, the immune system releases cytokines, proteins that help the body fight and ward off infection. When sleep is disrupted or inadequate, the immune response is depressed, making the body more susceptible to getting sick or to a more prolonged recovery. 

How Sleep Deprivation Affects Your Body
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Anyone who has suffered through a night of insomnia knows that the next day, they feel fatigued and sluggish; they may even feel as if they look significantly worse. But the effects of poor sleep are more than just mental; sleep deprivation, especially when it happens over the long term, is strongly associated with worse heart health, a weakened immune system, and a heightened risk of obesity, diabetes, sexual dysfunction, and even certain kinds of cancer. Understanding the myriad ways that poor sleep can hinder health may help motivate someone to make sure they’re consistently getting a good night’s rest.

Is sleeping too much tied to heart problems?

Many people are well-aware that sleep deprivation is bad for the heart. But some evidence also suggests that excessive sleep—that is, regularly sleeping significantly more than the seven to eight hours recommended by most experts—may come with a similar risk of cardiovascular disease or heart attacks. In our sleep-deprived society, many people see little risk in sleeping too much. But individuals who feel like they are consistently sleeping for extended hours at night, or who continue to feel groggy even after several nights of consistent sleep, should discuss the situation with their doctor; oversleeping may not be as benign as commonly thought.

Is there a link between sleep and diabetes?

Poor, disrupted sleep has been associated with a significantly increased risk for Type 2 diabetes. Though more research needs to be done to fully understand the connection, researchers speculate that sleep’s influence on metabolism, hormone production (including hormones that regulate appetite and satiety), and the body’s use of blood sugar may play a role. Similarly, insufficient sleep increases the risk of obesity, itself consistently associated with an increased occurrence of diabetes.

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