Sleep, circadian rhythm & workload
Also: Sleep risk
Isolation & ConfinementBehavioral Health & SleepIn-flightLEO short-durationLEO long-durationLunar surfaceMars transit & surfacePublicClinicianResearcher
- Short sleep (about 6 h/night) and circadian disruption are routine in spaceflight. ◆◆◆◇ Moderate · F
- Sleep medication use on the ISS is about 10 times higher than in ordinary outpatient medicine. ◆◆◆◇ Moderate · F
- NASA rates the operational risk 5×2 for every mission type. On the ISS it is "accepted with optimization"; for Mars it "requires mitigation". ◆◆◆◆ High · E
Proposed certainty (◆ High → ◇ Very low) and evidence-type tags: F flight · A analog · M model/animal · C computational · E expert/operational/standards. AI-proposed, pending reviewer confirmation. How to read the grades.
NASA risk title (verbatim)
Risk of Performance Decrements and Adverse Health Outcomes Resulting from Sleep Loss, Circadian Desynchronization, and Work Overload
NASA short title: Sleep · HRP element: Human Factors and Behavioral Performance (HFBP) · Status: Active [current research ongoing] [1]
What it is
This risk covers short sleep, a body clock out of step with the work schedule (circadian desynchronization) and too much work, and how they degrade performance and health [1].
Current evidence
- Crews sleep about 6 hours per night in flight, and their sleep and circadian misalignment grows [1].
- Work overload and scheduling problems are documented [1].
- Ground studies show these factors cause short-term problems with performance, mood and metabolism, even when people feel they have adapted. They are also linked to long-term disease risk [1].
- On the ISS, crew used sleep medications about 10 times more often than adults in ordinary outpatient medicine [4].
- In the 520-day Mars-500 simulation, crew members became less active over time, and their sleep duration and timing changed [5].
NASA’s risk posture
NASA scores each risk for each design reference mission (DRM) as likelihood × consequence (LxC). Both run from 1 (lowest) to 5 (highest) on the HSRB’s 5×5 matrix [1][3]. Each score comes with a disposition, such as “Accepted”, “Requires Characterization” or “Requires Mitigation”. These ratings were last approved by NASA’s Human System Risk Board (HSRB) in 3/2022 [1].
| Mission | Duration | In-mission (operations) | Long-term health |
|---|---|---|---|
| LEO | Short (under 30 d) | 5x2 · Accepted with Optimization | 3x1 · Accepted with Monitoring |
| LEO | Long (30 d–1 yr) | 5x2 · Accepted with Optimization | 3x1 · Accepted with Monitoring |
| Lunar orbit | Short | 5x2 · Requires Characterization | 3x1 · Accepted with Monitoring |
| Lunar orbit | Long | 5x2 · Requires Characterization | 3x1 · Accepted with Monitoring |
| Lunar orbit + surface | Short | 5x2 · Requires Characterization | 3x1 · Accepted with Monitoring |
| Lunar orbit + surface | Long | 5x2 · Requires Characterization | 3x1 · Accepted with Monitoring |
| Mars preparatory | Under 1 yr | 5x2 · Requires Mitigation | 4x2 · Requires Mitigation |
| Mars planetary | 730–1,224 d | 5x2 · Requires Mitigation | 4x2 · Requires Mitigation |
Copied from the Human Research Roadmap on 2026-10-14. Ratings change. Check the live record before citing.
Open knowledge gaps
NASA lists 2 knowledge gaps for this risk, 2 of them open as of 2026-10-14 [1]. Each gap ID links to its page on the Human Research Roadmap (HRR).
Show NASA’s gap list (verbatim)
| Gap | NASA gap statement | Status |
|---|---|---|
| Sleep-101 | Given each crew member will experience multiple spaceflight hazards simultaneously, we need to identify and characterize the potential additive, antagonistic, or synergistic impacts of multiple stressors (e.g., Space Radiation, Altered Gravity, Isolation, altered immune, altered sleep) on crew sleep-wake cycles and/or circadian shifting, health and/or CNS/cognitive functioning to identify any identified adverse individual or team crew health, and/or operationally-relevant performance outcomes. | Open |
| Sleep-102 | We need to identify and develop an integrated, individualized suite of scheduling tools that predict the effects of sleep-wake cycles and light on performance, with validated countermeasures and on-board systems to monitor, prevent and/or treat chronic partial sleep loss, work overload, and/or circadian shifting in spaceflight. | Open |
See also Open questions.
Active countermeasure research
- Lighting. NASA lists a flexible ISS lighting system as a promising countermeasure, not yet in routine use, with research and surveillance evaluating whether it works [1].
- Scheduling tools. NASA aims for an individualized suite of scheduling tools that predict how sleep and light affect performance, paired with validated countermeasures and onboard monitoring (gap Sleep-102) [1].
Project-level detail, including status, investigators and results, is in the NASA Task Book and on each HRR gap page.
Clinical articles
For practical, clinic-facing guidance, see:
Evidence profile
- Overall certainty
- ◆◆◆◇ Moderate (proposed)
- Evidence types
- F · Flight dataA · Terrestrial analogE · Expert / operational / standards
- Literature through
- 2026-10-14
- NASA source
- Human Research Roadmap risk page (last published 05/13/25; read 2026-10-14)
Requirements referenced 2
| Requirement | Title | Plain-language meaning |
|---|---|---|
| [V1 6001] | Circadian Shifting Operations and Fatigue Management | Manage schedule shifts and fatigue. |
| [V1 4014] | Completion of Critical Tasks | Planned work hours for critical tasks account for crew capability (workload, fatigue). |
IDs as published in NASA-STD-3001 Vol. 1 Rev C (2023-09-15) and NASA-STD-3001 Vol. 2 Rev F (2026-07-14). NASA-STD-3001 binds NASA programs; it is not a regulation for commercial flights. Paraphrased. Standards quick reference.
References 5
- NASA Human Research Roadmap. Risk record: “Risk of Performance Decrements and Adverse Health Outcomes Resulting from Sleep Loss, Circadian Desynchronization, and Work Overload”. Accessed 2026-10-14. humanresearchroadmap.nasa.gov/Risks/?i=100 NASA E
- NASA Human Research Program. Evidence report for the Sleep risk (approved April 11, 2016). humanresearchroadmap.nasa.gov/evidence/reports/Sleep.pdf NASA E
- Antonsen EL, et al. Updates to the NASA human system risk management process for space exploration. NPJ Microgravity. 2023;9:72. doi:10.1038/s41526-023-00305-z PMID:37679359 Peer-reviewed E
- Wotring VE. Medication use by U.S. crewmembers on the International Space Station. FASEB J. 2015;29(11):4417–4423. doi:10.1096/fj.14-264838 PMID:26187345 Peer-reviewed F
- Basner M, et al. Mars 520-d mission simulation reveals protracted crew hypokinesis and alterations of sleep duration and timing. Proc Natl Acad Sci USA. 2013;110(7):2635–2640. doi:10.1073/pnas.1212646110 PMID:23297197 Peer-reviewed A
Machine-checked on 2026-10-14: each URL resolved, each DOI's title/journal/year matched via Crossref, and claims were checked against the source text (abstract or full NASA page). Human verification against full text is still required before review. NASA documents are U.S. Government works (public domain) and are summarized with attribution; journal articles are summarized, not reproduced.
Article info
- Authors
- Pending (AI-assisted draft)
- Reviewer
- Pending review
- Last reviewed
- Pending review
- Literature through
- 2026-10-14
- AI-assisted
- Yes (disclosed)
- COI
- Pending
- License
- CC BY-SA 4.0
- Use
- Educational only · Disclaimer
- Cite this version
- Pending first edition