The use of sleeping pills reported by as many as three-quarters of astronauts who've gone into space is worrying because they can dull the ability to become wake and react quickly to emergencies, a study finds.
Anyone who has used sleeping aids to deal with a sleepless night is familiar with the "do not drive or operate machinery" warning and others prominently displayed on the medication's container.
Yet many astronauts, who arguably have to operate some of the most complex machinery on -- or more to the point, off -- Earth have turned to medicinal sleep aids, study researchers found.
An extensive study by U.S. researchers of sleeping patterns of astronauts on both the International Space Station and during space shuttle missions found "widespread use of sleeping medications such as zolpidem and zaleplon during space flight."
"Sleep deficiency is pervasive among crew members," says study lead author Laura K. Barger, a physiologist in the Division of Sleep and Circadian Disorders at Brigham and Women's Hospital in Boston.
Not only do they have trouble sleeping while in space, the researchers found; most astronauts are not even getting enough hours of sleep during the months of preparation in the run-up to their missions.
Complaints of sleep deprivation are common among astronauts beginning as much as 3 months before a mission as training becomes more intense, the researchers reported.
Resorting to sleeping pills once in space presents the risk of astronauts not being able to perform their duties optimally if suddenly awakened from sleep, for example in the case of any sort of emergency alarm, Barger says.
She cites a U. S. Federal Drug Administration caution against the use of sleeping pills by people engaged in hazardous occupations where full mental alertness and motor coordination is required.
"You have to weigh the benefits of hypnotics against those risks," Barger says. "We need to have better countermeasures to improve sleep."
NASA, which along with the National Space Biomedical Research Institute funded the study, issued a statement saying, "Our astronauts work in harsh, complex environments where they are sometimes subjected to uncomfortable and high stress situations."
The agency said it was committed to identifying and implementing measures designed to ensure astronauts could achieve the same quantity and quality of sleep while in space as is possible on Earth.
Barger agrees more effective measures are needed, as "sleep deficiency has been associated with performance decrements in numerous laboratory and field-based studies."
