Although its a common belief that 8 hours of sleep is required for optimal health, a six-year study of more than one million adults ages 30 to 102 has shown that people who get only 6 to 7 hours a night have a lower death rate. Individuals who sleep 8 hours or more, or less than 4 hours a night, were shown to have a significantly increased death rate compared to those whose who averaged 6 to 7 hours.
Researchers from the University of California, San Diego (UCSD) School of Medicine and the American Cancer Society collaborated on the study, which appeared in the February 15, 2002 issue of the Archives of General Psychiatry, a journal of the American Medical Association.
Although the data indicated the highest mortality rates with long-duration sleep, the study could not explain the causes or reasons for this association.
First author Daniel F. Kripke, M.D., a UCSD professor of psychiatry who specializes in sleep research, said we dont know if long sleep periods lead to death. Additional studies are needed to determine if setting your alarm clock earlier will actually improve your health.
But, he added individuals who now average 6.5 hours of sleep a night, can be reassured that this is a safe amount of sleep. From a health standpoint, there is no reason to sleep longer.
The study, which addressed sleep issues as part of the Cancer Prevention Study II (CPSII) of the American Cancer Society, also indicated that participants who reported occasional bouts of insomnia did not have an increased mortality rate, but those individuals who took sleeping pills were more likely to die sooner.
Insomnia is not synonymous with short sleep, the authors said in the article. Patients commonly complain of insomnia when their sleep durations are well within the range of people without sleep symptoms.
They added that physicians believe most patient complaints about insomnia are actually related to depression, rather tha
Contact: Sue Pondrom
University of California - San Diego