A new study suggests that peoplewho sleep 8 hours or more a night, or less than 4 hours, have a slightlyhigher risk of dying in a given time period than those who get 6 and 7hours of shut-eye.
However, the researchers notethat they can't be sure why some of the study subjects had longer or shortersleep periods, and there's no evidence that sleep patterns-or changingthem-can truly influence mortality risk.
Some sleep experts, includingthose at the National Sleep Foundation (NSF), agree.
Although the study reportsdata that is of interest, limitations in the study methodology restrictthe conclusions that can be reached, particularly about the amount ofsleep needed to sustain an individual's health, safety and well-being.
In the study researchers examinedthe findings of a previously conducted study that included, among otherthings, data on the sleep habits of 1.1million people men and women between the ages of 30 and 102.
The study subjects, friendsand family members of American Cancer Society volunteers, were interviewedin 1982 about diet, exercise, sleep and health problems and then followedup 6 years later.
Participants who reported sleeping8 or more hours or less than 4 or 5 hours a night experienced a slightlyhigher chance of dying-at least a 15%increase in risk -- within that time compared with those whoslept 7 hours a night.
Interestingly, only one ina thousand slept at the lower end of the time scale.
Furthermore, the researchers report that insomnia was not associated withexcess mortality, although the use of a prescription sleeping pill wasalso associated with a slightly increased risk of dying during the six-yearperiod.
The study does seem to indicatethat fewer than 8 hours of shuteye a night are not necessarily detrimentalto health.
The study was not designedto answer why sleeping longer may be deleterious or whether people couldextend their life spans by sleeping less. It is possible that people whosleep longer tend to suffer from sleep apnea, a condition in which impairedbreathing puts stress on the heart and brain. The need for sleep is akinto the need for food, in that getting less than people want may be betterfor them.
While agreeing that the riskof dying from reduced sleep is low, he added, "It's hard to knowif we shouldn't be worried about five hours of sleep -- if you are talkingabout being able to drive a truck a thousand miles the next day, beingable to concentrate, make important decisions, that's a whole other story."
The average American sleeps7 hours on weekdays, according to the 2001 Sleep in America Poll (conductedby the National Sleep Foundation). The new study shows that it is quitesafe to sleep five, six, or seven hours a night, and people who sleepless than eight hours do not need to worry.
The study's findings may leadthe public to be less concerned about insomnia -- a sometimes seriouscondition marked by an inability to sleep. Even mild sleep deprivationis associated with increased daytime sleepiness, which may lead to adverseoutcomes, such as accidents.
Insomnia is associated withimpaired quality of life, functional impairment, physical symptoms, andcoronary heart disease. Sleep is not bad for you and insomnia is not good.
Sleeplessness produces healthconsequences that were not measured in the study. The amount of sleepyou get impacts how alert you are, your risk for accidents, how you performat work and school. There's much more to life than how long you live.
The National Sleep Foundationemphasizes that substantial research serves as the basis for the recommendationthat adults obtain an average of seven to nine hours of sleep each night.
The group notes that individualswill require different amounts of sleep and that if someone sleeps 8.5hours a night and feels alert and energetic, it would be incorrect toreduce sleep time based on the study.
Archives of General PsychiatryFebruary 15, 2002;59:131-136
One needs to be carefulin evaluating these studies as 99 percent of the funding to support thistype of research is from pharmaceutical companies. While it does not appearthat this study was funded by the drug companies, the editorialist inthe journal are clearly paid by the drug companies that make sleepingpills.
Earlierresearch from the University of Chicago is quite clear that sleepingless than 6.5 hours will cause disruption in insulin receptor sensitivitywhich will increase one's risk for diabetes, obesity, and heart disease.
While sleeping more than8 hours may not be necessary, clearly sleeping much less than 7 hoursis likely to be highly detrimental for most people.
I am currently in the processof reviewing several books on chronobiology and hope to summarize someof the findings in the near future on this very important topic.
However, everyone agreesthat insomnia is not a good thing. If this is a problem for you, pleasebe sure to check out the first link for my sleeping guidelines.