Sleep-Wake Actigraphy and Light Exposure During Spaceflight-Long (Sleep-Long) examines the effects of space flight and ambient light exposure on the sleep-wake cycles of crewmembers during long-duration stays on board the International Space Station.Principal Investigator(s)
Johnson Space Center, Human Research Program, Houston, TX, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)ISS Expedition Duration:
September 2006 - March 2011
14,15,16,17,18,19/20,21/22,23/24,25/26Previous ISS Missions
Sleep-Short, a similar investigation was performed with short duration crewmembers during STS-104, STS-109, STS-111, STS-112, STS-113, STS-114, STS-121, STS-115, STS-116, STS-118, STS-120, STS-122, STS-123, STS-124, STS-125, STS-126, STS-127, STS-128, STS-129, STS-130, STS-131, and STS-132.
The success and effectiveness of manned spaceflight depends on the ability of crewmembers to maintain a high level of cognitive performance and vigilance while operating and monitoring sophisticated instrumentation. During short-duration space flights, crewmembers commonly experience sleep disruption and may experience misalignment of circadian (of or relating to biological processes occurring with a cycle of approximately 24 hours) phase during space flight. Both of these conditions are associated with insomnia, impairment of alertness, and cognitive performance.
There is little information on the effect of long-duration spaceflight on sleep and circadian rhythm organization. This experiment uses state of the art ambulatory technology to monitor sleep-wake activity patterns and light exposure in crewmembers on board the International Space Station (ISS). Subjects wear a small light-weight activity and light recording device (Actiwatch) for the entire duration of their mission. The sleep-wake activity and light exposure patterns obtained in-flight are compared with baseline data collected on Earth before and after space flight. The data collected increases understanding of how space flight affects sleep as well as aids in the development of effective countermeasures for long-duration space flight.
The information derived from this study will lead to a better understanding of the effects of space flight on sleep-wake cycles. The countermeasures that may be developed based on the findings of this study, could improve sleep during missions, which in turn will help maintain alertness and lessen fatigue of the crew during long-duration space flights.Earth Applications
A better understanding of insomnia is relevant to the millions of people on Earth who suffer nightly from insomnia. The advancement of state of the art technology for monitoring, diagnosing, and assessing treatment effectiveness is vital to the continued treatment of insomnia on Earth. This work has the potential to greatly benefit the health, productivity and safety of groups with a high prevalence of insomnia, such as shift workers and the elderly.
A total of 20 long-duration crewmembers are required as subjects for the experiment. Baseline data for each subject is collected for two weeks between Launch minus 120 (L-120) days and L–75, as well as from L-11 through L-0. Recovery in sleep patterns after space flight will be assessed from Return plus 0 (R+0) days to R+7.Operational Protocols
Crewmembers put on the Actiwatches as soon as possible upon entry into orbit and wear them throughout the flight. Crewmembers maintain sleep logs; they are required to keep the log for seven consecutive days, every three weeks or during three separate weeks throughout the mission that meet specific schedule criteria. Crewmembers download data from the Actiwatches every 26 days and change the battery at the end of the increment. On the last day of the mission, crewmembers take off and stow the Actiwatches.
Analysis of the Sleep-Long data is ongoing.
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