It is well-known, that sleep is an antistress adaptation factor, and human capacity for work depends on sleep quality. Also, excessive workload could lead to sleep disorders.
The aim of this research was to study sleep changes during ground simulation of an interplanetary manned flight “Mars-520”.
Night polysomnography of 6 healthy men was recorded before, 4 times during (6 weeks after the onset, 2 weeks before “Mars landing” (33th week of isolation), 2 weeks after the landing part of the experiment (41 week) and 6 weeks before the end (67 week)) and after the end of the 520-days isolation. Recordings scoring was performed among the standard criteria. We compared the sleep parameters (after transformation to normal distribution) between the periods of the experiment by repeated measure ANOVA. If ANOVA demonstrated significant difference (p<0.05), we performed pairwise comparison by Tukey's test. Additionally, we analyzed distribution of nights with low sleep efficiency in the periods by proportion test. Cutoff for sleep efficiency was 25% quartile.
Sleep efficiency decreased, sleep latency prolonged and delta-sleep latency shortened, especially 1,5 months before the end of the isolation. Frequency of nights with low sleep efficiency augment on the eve of the important for the crew events: landing simulation and the end of the isolation. Two weeks after Mars landing frequency of nights with low efficiency significantly decreased.