5 Things Sleeping Well Says About Your Health, According To Science

Many of the conversations that are had about sleep and health revolve around problems and disruptions: too much sleep, not enough, how sleep disorders form, and the many ways in which sleeping poorly can affect your health (of course, in a negative way). However, there's another side to the conversation. What does sleeping well say about your body and how it's currently faring? If you sleep like a log every night, you'll likely give no thought to this at all, but it turns out that good sleep can tell us several things about the state of your body, all of which are relevant to your overall health.

Restful, refreshing sleep that lasts eight or nine hours isn't as common as it should be among adults. The Center for Disease Control estimated in 2016 that one in three Americans doesn't get enough sleep, and the increase in electronic devices in the bedroom, which emit sleep-disrupting blue light, hasn't helped younger generations get healthy ZZZs. If you are among the lucky people who sleep without the need for supplements or sleep aids, don't wake up in the night or experience fatigue in the daytime, and have no real worries about your nighttime functioning, that's an important element of your health. Here's what good sleep can tell you about your body.

1You Have A Well-Functioning Body Clock

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The body clock isn't one thing: it's a complex and highly intricate system of cues and signals that involves every cell in the body, sending and receiving cues on when to sleep, when to eat, body temperature, metabolism and other cyclical factors. This circadian rhythm, as it's called, is controlled and influenced by many different things — and scientists are still discovering new elements of complexity in it. One thing we do know for sure, however, is that good, deep sleep is a symptom of a healthy body clock.

Alongside the circadian clock, which works on a roughly 24-hour cycle, there's another system involved in your sleeping. That system, explains the Harvard Healthy Sleepy center, is "the sleep/wake homeostat, which monitors our need for sleep based on how long we have been awake." These two interact to produce healthy, restful sleep.

The body clock doesn't just tell you when you go to sleep. It also affects your sleep quality; studies on magnesium, a key mineral in the maintenance of the body clock throughout the body, have discovered that it affects sleep quality and restfulness. If your circadian rhythms are disrupted — for instance, by jet lag — your sleep becomes more irregular and less satisfying, and your need for sleep becomes disconnected from your body's cues for rest.

Getting a good night's sleep means that these systems are purring along, and that has implications for many other mechanisms in the body. For instance, circadian rhythms have a big role in regulating metabolism — the process through which your body maintains energy and things that keep it alive — and good sleep is a signal that you're metabolically healthy. Internal clocks are also tied to your digestion, so you're more likely to have a healthy gut, too.

2Your Immune System Is Doing Well

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Some of the assumptions that can be made about a body that sleeps well can be inferred from what is known about bodies that don't. We know, for instance, that poor sleep has a serious effect on the immune system. Studies have shown that chronic sleep deprivation crashes the immune system, leaving you more vulnerable to infections, bacteria and passing germs because your immune response is less effective than usual.

The immune system is strongly linked to sleep, and requires it for proper functioning. A study in 2017, for instance, suggested that it's "immunoregulatory," or helps the immune system regulate and flourish. That means that, if you're getting your full eight hours of refreshing rest, the body's immune system is likely operating healthily and protecting you from threats, unless there are other factors interfering with it.

3You're Protected By Your Vaccinations

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One of the unusual health benefits of good sleep has only been discovered recently: that people with excellent sleep respond more strongly to vaccinations than sleep-deprived people. This is a fascinating development likely related to the strength of the immune system: vaccinations are better accepted by people whose immune systems are well-rested and capable of adapting to the vaccinations themselves. Dr. Michael Twery explained to the National Institutes of Health, "[W]ell-rested people who received the flu vaccine developed stronger protection against the illness." Sleeping well means that your vaccinations are protecting you against new threats.

4You Experience Strong Restorative Benefits

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When you sleep, your body does a lot of restorative work — and good, healthy sleep cycles give that restoration time to do its stuff. The link between sleep and restorative cycles is still little understood, says Harvard's Healthy Sleep center, but the evidence is persuasive: "many of the major restorative functions in the body like muscle growth, tissue repair, protein synthesis, and growth hormone release occur mostly, or in some cases only, during sleep. Other rejuvenating aspects of sleep are specific to the brain and cognitive function." Sleep has been shown to help injury recovery — so if you sleep well, your body is likely healing well from bumps in the road and tough exercise.

5You're Relaxed Rather Than Stressed

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One of the most-mentioned factors that interferes with sleep is stress. "[F]eeling stressed out increases your physiological and psychological arousal in ways that are incompatible with the state your body and mind need to enter relaxed, restorative sleep," notes the National Sleep Foundation. Dropping off easily and sleeping through the night indicates that while you may be experiencing stress, you're coping with it in ways that aren't heightening your arousal at night. People who practice mindfulness or exercise regularly, both of which are known stress-busters, are more likely to have deep, satisfying sleep, according to expert.

Overall, good, restful sleep shows that your overall health report card is likely pretty stellar. It's not a guarantee, though. If you sleep well but have other symptoms, your high-quality snoozes don't mean everything is automatically fine. And if your famously great slumber suddenly starts to become disrupted for no apparent reason, it's a good idea to see a doctor.