FRIDAY, Aug. 8, 2014 (HealthDay News) -- Lack of sleep is common among astronauts before and during spaceflight, and their widespread use of sleeping pills could pose a safety threat, a new study suggests.
Researchers analyzed the sleep habits of 64 astronauts on 80 space shuttle missions and 21 astronauts on International Space Station missions before, during and after their time in space.
In total, the team examined more than 4,000 nights of sleep on Earth and more than 4,200 nights of sleep in space, according to the study in the Aug. 8 issue of The Lancet Neurology.
NASA schedules 8.5 hours of sleep per night for crew members while in space, but astronauts' average amount of sleep per night was just under six hours on shuttle missions and just over six hours on space station missions.
Only 12 percent of sleep sessions on shuttle missions and 24 percent of space station missions lasted seven hours or more, compared with 42 percent and 50 percent, respectively, after the astronauts returned to Earth, the findings showed.
The researchers also found that lack of sleep began long before launch, with astronauts averaging less than 6.5 hours of sleep a night during the three months of training before they went into space. That's about half an hour less per night than the average American adult.
"Sleep deficiency is pervasive among crew members. It's clear that more effective measures are needed to promote adequate sleep in crew members, both during training and spaceflight, as sleep deficiency has been associated with performance decrements in numerous laboratory and field-based studies," study author Dr. Laura Barger, of Brigham and Women's Hospital and Harvard Medical School in Boston, said in a journal news release.
The use of sleep medications was also reported by three-quarters of space station crew members and 78 percent of space shuttle crew members. Sleep medications were used by crew members on more than 5
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