clinical trial
Circadian Disruption in the 354-Hour Lunar Day: Sleep Architecture and Melatonin Dynamics
Dr. Marta Kowalska
· European Lunar Health Authority
Lunar Sleep Medicine · Vol. 1, No. 2 · February 10, 2028
Abstract
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 characterize the lunar circadian phenotype.
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 demonstrated benefit: blue light blocking glasses after 20:00 habitat time (melatonin onset normalized in 60% of users), structured 0.5mg melatonin supplementation 30 minutes before target sleep time, and strict light-dark habitat scheduling including blackout of common areas after 22:00.
For residents experiencing severe circadian disruption, short-term low-dose zolpidem or melatonin receptor agonists are appropriate adjuncts while behavioral interventions take effect.
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 demonstrated benefit: blue light blocking glasses after 20:00 habitat time (melatonin onset normalized in 60% of users), structured 0.5mg melatonin supplementation 30 minutes before target sleep time, and strict light-dark habitat scheduling including blackout of common areas after 22:00.
For residents experiencing severe circadian disruption, short-term low-dose zolpidem or melatonin receptor agonists are appropriate adjuncts while behavioral interventions take effect.
Keywords
circadian, sleep, melatonin, cortisol, actigraphy, lunar day, insomnia, light