Most adults would benefit substantially from at least another hour of sleep at night, according to research at Detroit's Henry Ford Hospital, which was published in an issue of the journal Sleep.
The study observed a group of 24 healthy men, half of whom typically slept 7 hours a night and half of whom slept 8 hours. For a week, they went to bed early and slept an hour extra.When the men were asked to perform tests of attention and vigilance during that period - such as measuring driving skills or monitoring equipment as might be required in a nuclear power plant control room - both the long and short sleepers recorded measurable improvements.
The researchers say the results suggest that sleep maximization helps not just those who are sleep-deprived but allows those who are already functioning at a high level during the day to become even sharper.
According to Timothy Roehrs, a psychologist at the hospital, the study also counters the conventional wisdom that oversleeping is undesirable.