TO GIVE astronauts a good night's sleep, the best option is to cover them with electrodes. That's the conclusion from the latest investigation of orbital insomnia.
Crew members on space shuttle missions typically get only five or six hours of restless sleep each night. Some astronauts have resorted to sleeping pills, but these can affect alertness and reaction time. So for the past six years, NASA has given its astronauts melatonin, a hormone released by the body during darkness that makes us feel sleepy.
Charles Czeisler of Harvard Medical School in Boston knew that melatonin pills only seem to improve sleep for people whose bodies are not producing normal levels of melatonin. So he decided to test whether the pills were really helping shuttle astronauts.
During two shuttle flights last year, five astronauts took either melatonin or a placebo before sleep. On some days they wore a simple wristwatch monitor, while on others they wore numerous electrodes and monitors to record their sleep patterns.
Melatonin had no effect on either the quality of sleep or on the astronauts' performance in psychomotor tests next day. Surprisingly, the astronauts seemed to sleep best when they were covered with electrodes, even though some had joked that no one could sleep while wearing so many monitors.
Czeisler revealed his findings at a meeting at the National Academy of Sciences in Washington DC last week. He believes astronauts can't sleep because they are preoccupied by their duties. He suggests that covering them in monitoring equipment convinces them that sleep is an integral part of their mission, and that this allows them to relax enough to rest normally.
Author: Nell Boyce, Washington DC
New Scientist issue 24th April 1999
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