Related Experiment Videos
Sleep and circadian rhythms in four orbiting astronauts
T H Monk1, D J Buysse, B D Billy
1Sleep and Chronobiology Center, University of Pittsburgh School of Medicine, PA 15213, USA.
Journal of Biological Rhythms
|June 6, 1998
Summary
Astronauts experienced reduced sleep duration and less delta sleep during spaceflight, despite stable circadian rhythms and performance. These sleep changes were consistent throughout the 17-day mission.
Area of Science:
- Space physiology
- Sleep science
- Chronobiology
Background:
- Spaceflight poses unique challenges to human physiology, including sleep and circadian rhythms.
- Understanding these effects is crucial for astronaut health and mission success.
Purpose of the Study:
- To measure sleep and circadian rhythms in astronauts during a 17-day space mission.
- To investigate the isolated effects of microgravity on sleep and circadian regulation.
Main Methods:
- Polysomnography and sleep diaries for sleep recording.
- Core body temperature, actigraphy, and urine samples for circadian rhythm assessment.
- Computerized tests, questionnaires, and visual analogue scales for performance, mood, and alertness.
Main Results:
- Circadian rhythms remained stable in phase and amplitude in orbit, aligning with work/rest schedules.
- In-flight sleep was reduced (mean 6.1 hours), with a decrease in delta sleep observed.
- Mood, alertness, and performance remained satisfactory, with no further degradation from early to late flight.
Conclusions:
- Spaceflight on STS-78 did not disrupt astronauts' circadian rhythms or significantly impair performance and mood.
- However, spaceflight did lead to reduced total sleep time and decreased delta sleep.
- No further sleep degradation occurred as the mission progressed.