perspective
Circadian Disruption in the 354-Hour Lunar Day: Sleep Architecture and Melatonin Dynamics: Population Analysis
Dr. M. Bianchi
· Lunar Medical Research Cooperative
Lunar Sleep Medicine · Vol. 4, No. 3 · June 29, 2024
Abstract
Follow-up investigation building on prior work. The lunar day (29.5 Earth days) imposes a light-dark cycle incompatible with human circadian biology. Habitat lighting protocols designed to simulate a 24-hour cycle are partially effective but incompletely prevent circadian disruption. Actigraphy, cortisol, and melatonin data from 38 residents char...
Extended analysis and updated findings. The human circadian clock is calibrated to a 24-hour light-dark cycle through hundreds of thousands of years of evolution. In a lunar habitat, artificial lighting simulates this cycle with reasonable fidelity — but imperfectly. Light leakage through observation ports during the 14-day lunar 'day', habitat activity patterns, and irregular work schedules combine to create a challenging circadian environment.
We monitored 38 residents over 90 days using wrist actigraphy, morning cortisol, and midnight melatonin. Mean sleep efficiency was 78% (below the healthy adult norm of 85%). Melatonin onset was delayed by a mean of 47 minutes relative to pre-mission baseline. Cortisol awakening response was blunted, indicating disrupted hypothalamic-pituitary-adrenal axis function.
Interventions with d...
We monitored 38 residents over 90 days using wrist actigraphy, morning cortisol, and midnight melatonin. Mean sleep efficiency was 78% (below the healthy adult norm of 85%). Melatonin onset was delayed by a mean of 47 minutes relative to pre-mission baseline. Cortisol awakening response was blunted, indicating disrupted hypothalamic-pituitary-adrenal axis function.
Interventions with d...
Keywords
circadian, sleep, melatonin, cortisol, actigraphy, lunar day, insomnia, light