Actiwatch (Actiwatch) - 05.13.15
The Actiwatch is a waterproof, nonintrusive, sleep-wake activity monitor worn on the wrist of a crewmember. The device contains a miniature uniaxial accelerometer that produces a signal as the subject moves. The data are stored in nonvolatile memory within the Actiwatch until they are downloaded for analysis. Science Results for Everyone
Information Pending Facility Details
Suzanne McCollum, Johnson Space Center, Houston, TX, United States
Cambridge Neurotechnology Ltd., Cambridge, MA, United Kingdom
Sponsoring Space Agency
Japan Aerospace Exploration Agency (JAXA)
Japan Aerospace Exploration Agency
ISS Expedition Duration
September 2006 - March 2011
Previous ISS Missions
The Actiwatch has supported investigations on several space shuttle missions.
- The Actiwatch monitor provides data on the amount of ambient light the subject is exposed to and the amount of movement produced by the subject.
- The data collected from the Actiwatch is used to determine if space travel has an impact on the sleep-wake patterns of crewmembers.
The Actiwatch is a small, lightweight, wrist-worn device that simultaneously detects body movement and light intensity. It is used to evaluate sleep-wake adaptation and circadian cycle. The device is battery powered and can be used to collect data continuously in intervals ranging from 90 hours to 227 days depending on the sampling rate. The Actiwatch's internal, nonvolatile memory and programming allows it to store data indefinitely until it can be downloaded. Crewmembers will put on the Actiwatch as required by the investigation, download data from the Actiwatch as needed, and change the battery at the end of the increment. The Actiwatch provides computer software for setup and data retrieval via a RS-232 serial port connection to a personal computer (PC). The PC must be IBM compatible and have a 486 processor (minimum); 8-MB RAM (minimum); Windows 95, Windows 98, or Windows NT 4.0 or higher; a 100-MB hard drive; a 9-pin RS-232 serial port; and Super Video Graphics Array 9 SVGA (800 x 600 pixels required to display all data displays).^ back to top
- Crewmembers wear Actiwatches for a period specified by the investigators.
- The Actiwatch records wrist activity, allowing investigators to estimate the crewmember's activity, and records the amount of light the crewmember is exposed to.
Ground Based Results Publications
Monk TH, Buysse DJ, Billy BD. Using daily 30-min phase advances to achieve a 6-hour advance: Circadian rhythm, sleep, and alertness. Aviation, Space, and Environmental Medicine. 2006 Jul; 77(7): 677-686. PMID: 16856351.
NASA Image: S109E6062: View of STS-109 Commander Scott Altman activating the Actiwatch while seated at the pilot's station on the orbiter Columbia's forward flight deck.
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