The Relationship Between Sleep and Life Expectancy

Woman awake in bed next to a sleeping man

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Though it may seem counterintuitive, sleep is a busy time for your body. Various processes are at work that help everything from your cardiovascular system to your brain function at their best. It's because of this that getting enough sleep can improve your overall health, which may help boost your longevity. While inadequate sleep can have the opposite effect, so too can too much sleep.

Ultimately, finding the sweet spot where you're getting just the right amount of sleep for your body⁠ can contribute to a long and healthy life.

Research suggests that regularly sleeping for less than seven hours a night can have negative effects on the cardiovascular, endocrine, immune, and nervous systems. Side effects of sleep deprivation can include obesity, diabetes, heart disease, and hypertension, anxiety, depression, and alcohol abuse.

Why Your Body Needs Sleep

The point of sleep is not just to help you feel more refreshed, but to allow the cells in your muscles, organs, and brain to repair and renew each night. Sleep also helps regulate your metabolism and how your body releases hormones. When these processes are out of whack due to a lack of sleep, it can increase your risk of health problems.

While sleep could be affecting your risk on its own, it's also possible that an underlying issue could be affecting your rest. For example, poor sleep is linked to heart disease and obesity, but it could also be that pre-existing heart disease and obesity is leading to breathing problems like sleep apnea, which is negatively affecting your sleep, and, as a result, your overall health and longevity.

Sleeping too little also puts you at risk for being involved in potentially fatal accidents. A 2014 study found that sleeping six hours per night increases your risk of having a car crash by 33% compared to sleeping seven or eight hours a night. The researchers concluded that 9% of all motor vehicle accidents could be attributed to people sleeping less than seven hours a night.

Health Risks of Too Much Sleep

It's not just too little sleep that can be harmful. Sleeping too much can be a sign of health problems, too. In one study, sleeping for a long duration—which was characterized as more than 10 hours a night—was associated with psychiatric diseases and higher BMI, but not with the other chronic medical conditions related to too little sleep.

It's not likely that sleeping too much causes these issues, but rather that oversleeping could be a signal something is wrong. For example, excess sleepiness is a symptom of depression. If you find yourself wanting to sleep more than usual, consult with a healthcare provider about your symptoms.

What Is the Best Sleep Duration for Longevity?

Research indicates that the sweet spot for sleep duration is seven or eight hours a night. However, the amount of sleep that a person needs can vary from individual to individual.

In one study, researchers followed over 21,000 twins for more than 22 years. They asked questions about the twins' sleep habits and looked at their longevity. Twins make great research subjects because most of them grow up in the same environment and have the same, or similar, genetic makeups. Because of this, researchers can isolate the impact of a behavior (say, sleep duration) on an outcome (like longevity).

The participants were asked questions at the beginning and end of the study. The questions concerned sleep duration, use of sleep medications, and quality of sleep. What they found was that if people slept less than seven hours a night or more than eight hours a night, they had an increased risk of death (17% to 24%). Using sleep medications, which indicates trouble sleeping, also increased the risk of mortality by about a third.

How to Sleep Better Tonight

If you aren't currently getting the sleep you need, there are steps you can take clock more Zzzs:

  • Have a consistent to-bed and wake-up time, even on weekends.
  • Avoid using electronics before bed, and store them overnight somewhere other than your bedroom.
  • Keep your bedroom as dark as possible.
  • Don't eat or drink alcohol or caffeine close to bedtime.
  • Exercise regularly.
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