The NASA-funded study, detailed in this month's Aviation, Space and Environmental Medicine, was designed to examine the protocols the space agency uses to assign sleep-wake schedules that ensure astronauts are always able to handle their demanding tasks at peak performance. The findings suggest changes should be made in the way NASA schedules sleep periods on missions, but also have meaning for anyone who has had to deal with a significant time change and still function.
"Many of us find that we have to change our sleep schedule, perhaps to accommodate work or school start times, or a change in our commute time," said Timothy H. Monk, Ph.D., professor of psychiatry at the University of Pittsburgh School of Medicine and lead author. "We often wonder if we should make the change all at once, or more gradually over several days or weeks. This research has the eventual aim of helping us make that decision in the best way possible."
According to Dr. Monk, early in the history of manned space flight, NASA realized that it had to have a method for assigning sleep periods to correspond to astronauts' biological clock rhythms if they were to get enough rest to do their assignments. "If they scheduled sleep for the wrong time, an astronaut could end up having disrupted and unrefreshing sleep, leaving them feeling tired and irritable, and perhaps more apt to make mistakes."
Getting the right amount of sleep at the right time is more complicated in space than it is on Earth. On Earth, people are used to having time cues tell their bodies when it is time to sleep
or to wake up. The strongest of these is the 24-hour day-night cycle, which comes from the fact that we live and have evolved on a planet with a 24-hour rotation. Like most a