If you're feeling wide awake when everyone else is sleeping, new research on sleep disorders in blind people, reported in the Oct. 12 issue of The New England Journal of Medicine , may help you get back in sync. It illustrates the importance of the biological clock in sleep-wake regulation, and shows that 'treating' the clock can 'treat' some sleep disorders. Dijk, who is a chronobiologist at the University of Surrey in Guildford, England, was not involved in the study. Normally, our body clock is set for a cycle slightly longer than 24 hours, which is why we tend to sleep later each morning, then go to bed later each night if we have time off and don't set the alarm. But the 24-hour cycle of daylight and darkness tends to get us back on track.
Blind people drift later each day.
He's an associate professor of medicine at Hokkaido University in Sapporo, Japan, and was not involved in the study. In Lewy's study, seven totally blind subjects with sleep disturbances were given either melatonin or a sugar pill one hour before their preferred bedtime for several weeks. After their sleep patterns were recorded, each patient was switched over to the other treatment. Neither the patients nor the nurses knew which medication was being given. Before treatment and while taking the sugar pill, all seven subjects had sleep problems related to an abnormal daily cycle.