EFFECTS OF MICROGRAVITY AND ENVIRONMENTAL-FACTORS ON SLEEP

Over the past 10 years, four Russian biosatellites have been launched in orbit for 7-14 days, with two rhesus monkeys onboard to study the e ffects of flight on their sleep. Recording of electrophysiological par ameters (EEG, EMG, EOG, ECG) in these subjects was facilitated during resting periods since they had previously been implanted with electrod es, The analysis of polygraphic recordings obtained in flight shows ch anges in the structure and quality of sleep as compared to pre- and po st-flight recordings. Nocturnal waking and light sleep increased while deep sleep declined. Rapid eye movement sleep seemed to have its own course of change, increasing during the first days of flight, and decr easing thereafter. We suggest some hypotheses to explain these changes in relation to microgravity but also consider environmental factors.