MONDAY, Jan. 7 (HealthDay News) -- Prolonged spaceflight could have a negative effect on astronauts' sleep, performance and mood, according to a new study.
After monitoring a crew participating in a simulated 520-day mission to Mars, researchers from the Perelman School of Medicine at the University of Pennsylvania and the Baylor College of Medicine found prolonged confinement resulted in sleep loss, fatigue, stress, mood changes and conflicts. They noted these consequences must be addressed to allow astronauts to adapt to deep spaceflight.
"The success of human interplanetary spaceflight, which is anticipated to be in this century, will depend on the ability of astronauts to remain confined and isolated from Earth much longer than previous missions or simulations," the study's co-lead author, David Dinges, chief of the division of sleep and chronobiology in the department of psychiatry at the Perelman School of Medicine, said in a University of Pennsylvania news release.
"This is the first investigation to pinpoint the crucial role that sleep-wake cycles will play in extended space missions," he added.
On June 3, 2010, a 550 cubic meter confinement facility resembling a spacecraft was closed with a six-person international team of astronauts on board. The team was expected to conduct more than 90 experiments and other tasks so researchers could assess the effects of long-term space flight on their psychological and medical well-being.
To examine the astronauts' rest-activity patterns, performance and psychological responses, the researchers recorded their body movements and light exposure, and monitored changes in their activity levels, sleep, alertness and workload.
The study found that the team became more sedentary as time passed. Over the course of the mission they moved less and slept or rested more. Most of the astronauts also had problems with sleep quality, reduced alertness and altered sleep-wake intervals, suggesting a disruption in their circadian rhythm.
The researchers concluded that astronauts must travel in spacecraft and live in ways that mimic the Earth's sleep-wake cycles, including light exposure, meal times and exercise throughout a prolonged space mission. They noted that their findings also have implications for other people who are not astronauts that lead sedentary lifestyles with disrupted sleep and prolonged exposure to artificial light.
"A takeaway message from this line of research is the life-sustaining importance that healthy sleep duration and timing plays for everyone," Dinges noted. "As a global society, we need to reevaluate how we view sleep as it relates to our overall health and ability to lead productive lives. Whether it is an astronaut being challenged to reach another planet or a newborn baby just learning to walk, the human body's need for sleep is as essential as our need for food and water, and integral to our ability to thrive."
The simulation of the Mars mission was developed by the Institute for Biomedical Problems of the Russian Academy of Sciences, and partially sponsored by the European Space Agency.
The study was published online Jan. 7 in the journal Proceedings of the National Academy of Sciences.
The U.S. National Institute of Neurological Disorders and Stroke has more about sleep.
-- Mary Elizabeth Dallas
SOURCE: University of Pennsylvania, news release, Jan. 7, 2013
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