FRIDAY, July 25 (HealthDay News) -- The elderly have a lower tendency to sleep during the day and sleep about 1.5 hours less per day than younger people, which could have implications for age-related insomnia, researchers report in the Aug. 5 issue of Current Biology.
Elizabeth B. Klerman, M.D., Ph.D., from Harvard Medical School in Boston, and Derk-Jan Dijk, Ph.D., from the University of Surrey in Guildford, United Kingdom, examined sleep duration and structure at home and in the hospital for three to seven days in 18 older (60-76 years old) and 35 younger (18-32 years old) healthy men and women.
The researchers found that the older subjects initially had less daytime sleep propensity. Total daily sleep duration fell during the experiment to a mean of 7.4 hours in older adults and 8.9 hours in younger adults. Rapid- and non-rapid-eye-movement sleep were about equally responsible for the decline, the report indicates.
"Thus, in the absence of social and circadian constraints, both daytime sleep propensity and the maximal capacity for sleep are reduced in older people," Klerman and Dijk conclude. "These data have important implications for understanding age-related insomnia."
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