How much sleep is enough, or how much sleep is too much has been a controversial topic for many years? Regardless of the amount needed, sleep has been well acknowledged to affect everything from our athletic performance to our income according to a recent Time article (June 10, 2008) Daniel Kripke, co-director of research at the Scripps Clinic Sleep Center in La Jolla, California recently looked at this incredibly important question. In 2002, he studied death rates of over 1 million adults in the U.S. as part of a cancer prevention study, and reported their average nightly amount of sleep. His results were very surprising, and more recently they’ve been corroborated by similar studies in Europe and East Asia. The following is his explanation of the results.
Question: How much sleep is ideal?
Answer: Recent studies have found that people who sleep between 6 ½ hours to 7 ½ hours a night according to their report live the longest. People who fall out of that range, sleeping more than 8 hours or less than 6 ½ hours do not live quite as long. According to recent research, sleeping too long has just as much risk as sleeping too little. The biggest surprise is that sleeping too much seems to be more than eight hours. These studies have found in fact, that sleeping 8½ hours might be a little worse than sleeping only five.
Morbidity and sickness seem to form a U-shaped curve, with very short sleep and very long sleep both being associated with many illnesses such as obesity, depression and heart disease, as well as others. The ideal amount of sleep however for different health measures isn’t quite as conclusive. The data seems to indicate that for some health conditions the ideal amount of sleep needed is 7 or 8 hours, while other health conditions seem to indicate that 6 and some even 9 hours would be ideal. According to this research, diabetes for example, was lowest among 7-hour sleepers. The measures for the various conditions weren’t as clear and definite as the mortality data.
“I think we can speculate [about why people who sleep 6.5 to 7.5 hours live longer], but we have to admit that we don’t really understand the reasons. We don’t really know yet what is cause and what is effect” stated Kripke . “So we don’t know if a short sleeper can live longer by extending their sleep, and we don’t know if a long sleeper can live longer by setting the alarm clock a bit earlier. We’re hoping to organize tests of those questions.”
The reasons he wanted to publicize this information was that he wanted to prevent a lot of insomnia and distress just by telling people that “short sleep is OK”. “We’ve all been told you ought to sleep eight hours, but there was never any evidence. A very common problem we see at sleep clinics is people who spend too long in bed.” Kripke then concluded by saying “They think they should sleep eight hours or nine hours, so they spend eight or nine hours in bed, with the result that they have trouble falling asleep and they wake up a lot during the night.” Unfortunately, a lot of the problem with insomnia is that people lie in bed and worry about it, according to many health experts.
There have been a large amount of controlled studies in Great Britain and other parts of Europe as well as in the United States, that show that insomnia treatment frequently begins with getting out of bed when you are not sleepy, and restricting your time in bed may actually help people to sleep better. They frequently get over their fear of going to bed and become more confident that when they get into bed that they will sleep. In conclusion, frequently spending less time in bed may actually make your sleep better in many cases. This is almost undoubtedly a much more powerful and effective long-term treatment for insomnia than taking sleep medications.
Information adapted from Time article by Laura Blue (June 10, 2008) How Much Sleep Do You Really Need?
Additional Information and webpage by Paul Susic Ph.D Licensed Psychologist