Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights
Open accessAbstract
Sleep, circadian rhythm, and neurobehavioral performance measures were obtained in five astronauts before, during, and after 16-day or 10-day space missions. In space, scheduled rest-activity cycles were 20–35 min shorter than 24 h. Light-dark cycles were highly variable on the flight deck, and daytime illuminances in other compartments of the spacecraft were very low (5.0–79.4 lx). In space, the amplitude of the body temperature rhythm was reduced and the circadian rhythm of urinary cortisol appeared misaligned relative to the imposed non-24-h sleep-wake schedule. Neurobehavioral performance decrements were observed. Sleep duration, assessed by questionnaires and actigraphy, was only ∼6.5 h/day. Subjective sleep quality diminished. Polysomnography revealed more wakefulness and less slow-wave sleep during the final third of sleep episodes. Administration of melatonin (0.3 mg) on alternate nights did not improve sleep. After return to earth, rapid eye movement (REM) sleep was markedly increased. Crewmembers on these flights experienced circadian rhythm disturbances, sleep loss, decrements in neurobehavioral performance, and postflight changes in REM sleep.
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Loss of gravity resulted in altered circadian rhythmicity and impaired sleep in astronauts during a space mission.
“For example, studies in astronauts during a space mission have shown that loss of gravity resulted in altered circadian rhythmicity and impaired sleep (Dijk et al., 2001).”
From Sex-specific association of the lunar cycle with sleep (2022) · cites this paper as Dijk et al., 2001
The Abstract reports circadian rhythm disturbances and reduced sleep duration and quality in astronauts during spaceflight. But it says the mechanisms of sleep reduction have not been established, and the Conclusion says the causes of the observed changes could vary. The paper does not establish that loss of gravity caused them (page numbers were not provided for these passages). (LLM, conf=0.88)
Experimental — accuracy not yet measuredCircadian rhythms controlling sleep timing and quality are affected by non-photic cues, including gravity.
“Besides light, circadian rhythms controlling sleep timing and quality are affected by non-photic cues, including gravity.”
From Sex-specific association of the lunar cycle with sleep (2022) · cites this paper as Dijk et al., 2001
The introduction (page not provided) says that spaceflight changes both light exposure and gravitational forces and raises their potential impact on sleep and circadian rhythms. The Illuminance and Circadian Parameters section reports circadian abnormalities during flight, but attributes the failure to maintain synchrony to insufficient light exposure and drive from the sleep–wake schedule; it does not establish gravity as a cue affecting circadian rhythms. The claim states that effect more firmly than the paper supports. (LLM, conf=0.85)
Experimental — accuracy not yet measuredAstronauts sleep only about six hours per night, resulting in chronic sleep deprivation over time.
“Although the use of sleep-promoting drugs is common, astronauts sleep only about six hours per night, resulting in chronic sleep deprivation over time9–11.”
From Effects of total sleep deprivation on performance in a manual spacecraft docking task (2024) · cites this paper as [10]
Circadian rhythms, including melatonin rhythms, are involved in different aspects of facilitation of sleep.
“Circadian rhythms, including melatonin rhythms, are involved in different aspects of facilitation of sleep 57, 58.”
From The inner clock-Blue light sets the human rhythm (2019) · cites this paper as [58]
Previous research has noted increases in core body temperature during spaceflight and impaired thermoregulation during space analogs, but these studies were limited to short missions and did not investigate the effect of acute physical exercise on core body temperature.
“While previous research has noted increases in CBT during spaceflight15–17 and impaired thermoregulation during space analogs, i.e. head-down tilt bed rest18, these studies were limited to short missions and did not investigate the effect of acute physical exercise on CBT.”
From Increased core body temperature in astronauts during long-duration space missions (2017) · cites this paper as [15]
Earlier studies on core body temperature in space were short-term missions, spanning a maximum of 8-16 days of spaceflight.
“However, these studies were short-term missions, spanning a maximum of 8–16 days of spaceflight.”
From Increased core body temperature in astronauts during long-duration space missions (2017) · cites this paper as [15]
In earlier studies, higher resting core body temperature remained elevated throughout the stay on the ISS and returned to baseline 10 days after landing.
“In this case the higher resting CBT remained elevated throughout the stay on the ISS and finally returned to baseline 10 days after landing; these findings are also in line with observations of Dijk et al.15.”
From Increased core body temperature in astronauts during long-duration space missions (2017) · cites this paper as [15]
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References 37 · Cited by 268
Research works printed but not linked: 2
- Achermann P and Borbe ´ly AA. Simulations of circadian sys- tem and vigilance during space missions. In: Advances in Space Biology & Medicine, edited by Bonting SL. Greenwich, Canada: JAI, 1996, vol. 5, p 201-212.
- Aschoff J. Significance of circadian rhythms for spaceflight. In: Proceedings of the Third International Symposium on Bioastro- nautics and the Exploration of Space, edited by Bedwell TC and Strughhold H. Brooks Air Force Base: Aerospace Medical Divi- sion (AFSC), U.S. Air Force, 1965, p. 465-484.
- Authors
- Dijk, D.-J., Neri, D. F., Wyatt, J. K., Ronda, J. M., Riel, E., Ritz-De Cecco, A., Hughes, R. J., Elliott, A. R., Prisk, G. K., West, J. B., & Czeisler, C. A.
- Affiliations
- Brigham and Women's Hospital (US)
- Ames Research Center (US)
- Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115;
- University of California San Diego (US)
- ORCID
- Venue
- American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
- Publisher
- American Physiological Society
- Published
- 2001-11-01
- Volume
- 281
- Issue
- 5
- Pages
- R1647-R1664
- ISSN
- 0363-6119 (ISSN-L)
- 1522-1490
- OpenAlex
- W1905507378
- Cited by
- 268
- References
- 37
- Citations by year
- 2026: 8 · 2025: 12 · 2024: 20 · 2023: 9 · 2022: 20 · 2021: 24 · 2020: 13 · 2019: 14 · 2018: 17 · 2017: 8 · 2016: 8 · 2015: 11 · 2014: 9 · 2013: 9 · 2012: 12
- FWCI
- 3.19
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- American Journal of Physiology-Regulatory, Integrative and Comparative Physiology (publishedVersion)
- PubMed (publishedVersion)
- Open Research (University of Surrey) (submittedVersion)
- Surrey Research Insight Open Access (The University of Surrey) (submittedVersion)
- Funders
- National Aeronautics and Space Administration (NCC958)
- Massachusetts Institute of Technology
- National Space Biomedical Research Institute (NCC 9‐58)
- Ames Research Center
- University of California, San Diego
- Army Research Institute for the Behavioral and Social Sciences
- U.S. Army Research Institute of Environmental Medicine
- Topics
- Health Sciences › Medicine › Physiology › Spaceflight effects on biology
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
- Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
- Keywords
- circadian rhythm, sleep, spaceflight, astronauts, neurobehavioral performance, light-dark cycle, body temperature rhythm, urinary cortisol, sleep duration, slow-wave sleep, REM sleep, melatonin, sleep deprivation, circadian misalignment
- MeSH terms
- Activity Cycles, Adult, Body Temperature, Circadian Rhythm, Female, Humans, Hydrocortisone, Lighting, Male, Melatonin, Middle Aged, Psychomotor Performance, Surveys and Questionnaires, Sleep, Sleep, REM, Space Flight, Time Factors, Polysomnography, Photoperiod, Astronauts, Spacecraft
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