How much sleep do you really need? Probably a lot less than you think, says one expert. It's well known that a good night's sleep is essential for health. But oversleeping has been linked to a host of medical problems, including:
Diabetes: In a study of almost 9,000 Americans, researchers found a relationship between sleep and the risk of diabetes. People who slept more than nine hours each night had a 50 percent greater risk of diabetes than people who slept seven hours per night. This increased risk was also seen in people who slept less than five hours per night.
Obesity: Sleeping too much could make you weigh too much, as well. One recent study showed that people who slept for nine or 10 hours every night were 21 percent more likely to become obese over a six-year period.
Headaches: Sleeping longer than usual can cause head pain. Researchers believe this is due to the effect oversleeping has on certain neurotransmitters in the brain, including serotonin. People who sleep too much during the day and disrupt their nighttime sleep may also find themselves suffering from headaches in the morning.
Back pain: There was a time when doctors told people suffering from back pain to head straight to bed. But those days are long gone -- they now recommend against sleeping more than usual, when possible.
Depression: Roughly 15 percent of people with depression sleep too much. This may in turn make their depression worse, because regular sleep habits are important to the recovery process. In fact, in certain instances, sleep deprivation can be an effective treatment for depression.
Heart disease: A careful analysis of the data from the Nurses' Health Study, which involved nearly 72,000 women, showed that women who slept nine to 11 hours per night were 38 percent more likely to have coronary heart disease.
Death: Multiple studies have found that people who sleep nine or more hours a night have significantly higher death rates. No specific reason for this correlation has been determined.
Meanwhile, the common assertion that you need eight or more hours of sleep each night may be incorrect. According to some experts, most people need less than eight hours of sleep each night. Several large studies over the past 40 years show that the average healthy adult sleeps for seven to seven-and-a-half hours a night, and that should be plenty from a physical perspective. Some adults need even less than that and can function normally on just five hours of sleep a night.