Getting 8 hours? You may be sleeping TOO much

How many hours of sleep should you get each night for optimal health?

If you’re like me, your knee-jerk reaction to that question is “8 hours.” But research is shedding new light on the conventional wisdom about sleep – and the new answers it provides may surprise you.

Sleep’s “gold standard” may be deadly

Scientists analyzed the sleep habits of more than 1.1 million people who participated in the American Cancer Society’s (ACS) Cancer Prevention Study II. The study subjects were mainly friends and relatives of ACS volunteers, with ages ranging from 30 and 102. They all completed health questionnaires in 1982; among other things, the survey asked the average number of hours they slept each night, how many times a month they experienced insomnia, and how often they had used prescription sleeping pills in the last month. Then the researchers followed up with the participants six years later to determine if they were still alive and, if not, what had caused their deaths.

When they analyzed the data, the scientists found some interesting trends. According to the study, people who reported sleeping eight hours or more had a “significantly increased mortality hazard.” In fact, people who reported sleeping more than 8 1/2 hours per night were 15 percent more likely to have died during follow up than those who slept less.

In contrast, less sleep wasn’t as dangerous until the average sleep hours got down to very low numbers. For example, to match that 15% increased risk, women had to sleep less than 3 1/2 hours per night, and men had to sleep less than 4 1/2 hours.

No sleep is still better than drug-induced sleep

Interestingly, the study found no association between periodic insomnia and morbidity. But it DID find a significant link between prescription sleeping pill use and high risk of death. There were some limitations to this aspect of the study; the data didn’t specify the type of prescription drugs taken, or identify specific compounds in them that might have caused this effect. And the authors note that the most common types of sleeping pills used when the data was collected have largely been replaced by a new drug class that may not have the same effect. But it is an important point to consider if you use, or have considered using, prescription sleeping pills on a regular basis.

So if you’ve been thinking that you don’t get enough sleep, think again. This study suggests that it’s best to sleep between 6 1/2 and 7 1/2 hours each night – and that sleeping even less than that on a regular basis won’t hurt you. And it also shows that you may be better off getting less sleep – and even going through periodic bouts of insomnia – than taking the prescription sleeping pills used by participants.

Then again, if you’ve trained yourself to get 10 hours of shut-eye each night, you might want to re-examine that habit as well. Previous studies have linked too much sleep with depression and other ailments. If you think you may be sleeping too much, talk to your doctor about what it might mean and what you might do to correct any underlying problems.

We all know that the body needs adequate sleep to heal itself and remain healthy. And everyone’s sleep needs are different, based on a whole host of factors. But this study shows that you can have too much of a good thing where sleep is concerned.

Source: Archives of General Psychiatry 2002;59:131-136

Copyright 1997-2002 by Institute of Health Sciences, L.L.C.