WASHINGTON—Try sleeping on your head, strapped in with a bungee cord, in a noisy little room with five other people. Oh, and the air's stale, the windows don't open and the world outside cycles from daylight to darkness 15 times a day.
That's what former NASA astronaut Jerry Linenger endured for 143 nights in space, most of it aboard Mir, the old Russian space station. Mars-exploring astronauts would have to put up with the same nasty conditions for more than a year.
Although NASA has almost no money for sleep research these days, a new low-budget study is due to head aloft with the next shuttle launch, tentatively in May. It's a collaboration among two Irish researchers, a California maker of vest-like lightweight shirts that measure vital signs and a German astronaut who's willing to wear one. The European Space Agency is picking up the tab.
According to Linenger, a physician, there's no question that sleep deprivation degraded his fellow astronauts' performance. "I'd be talking to them and they'd literally be falling asleep," he recalled. "They'd go back to work and 15 minutes later they'd be falling asleep again."
Sleeping pills help. But they're not perfect, and astronauts in orbit still suffer disruption of their circadian rhythms, the behavioral and physiological pace set by Earth's 24-hour rotation. Although astronauts keep diaries of their sleep and its quality, it's proved hard to study closely. That's partly because astronauts balked at the half-hour it took them to put on the traditional oversized hairnet with electrode tentacles that researchers use to monitor sleep.
"Sleep is their free time, and they don't want to be lab rats when they're doing it," said Derek O'Keeffe, a University of Limerick biomedical engineer and research partner in the new sleep study.
O'Keeffe and Marc O'Griofa of University College Dublin will use an off-the-shelf monitoring shirt, made by VivoMetrics of Ventura, Calif., which requires no costly design or testing because it's been approved since 2002 by the U.S. Food and Drug Administration.
Wires embedded in the 8-ounce sleeveless Lycra garment measure respiration while an electrocardiogram gauges heart rate. A tiny monitor powered by a rechargeable 7.4-volt lithium battery records up to 24 hours of results on mini-cards.
The health-care provider Kaiser Permanente uses VivoMetrics' LifeShirt to diagnose sleep disorders in children, and its use in sleep research is growing. The shirt also is being eyed as a cost-saving way in the future to monitor patients' chronic illnesses at home.
German astronaut Thomas Reiter, who's heading into space on the shuttle Discovery's next mission, is the guinea pig. He intends to wear a LifeShirt for five nights at a time at the beginning, middle and end of his projected 150-day stay on the International Space Station.
Linenger said his strategy was to don eyeshades and force himself to go to sleep at midnight Moscow time, in deference to his Russian hosts, and wake up at 6 a.m. Moscow time. In his weightless world, he strapped himself to the bulkhead with a bungee cord to mimic the weight of blankets and gravity.
Despite his efforts, sleeping aboard the space station "was like sleeping at a noisy motel," he said, "and after four months of not getting much deep sleep at night, I started losing it."
On short missions, astronauts can tough it out because they're "very fit and very disciplined," said Tim Monk, a professor of psychiatry at the University of Pittsburgh Medical School.
"But on long-duration missions, sleep starts to disintegrate," he said, "and that's an issue we've got to start taking seriously."