Effects Of Sleep Deprivation Of Different Sections On Sleep Architecture, Cortisol And Cognition Function In Healthy Men

Objectives: To study the effects of short-term sleep deprivation on sleep architecture, cortisol and cognition function in healthy men, and also to investigate the relationship between sleep architecture, cortisol and cognition function.Methods: 10 healthy men (age, 21.9±1.2 years) participated in the program and were randomly divided into two groups, I and II. Participants in group I only had a sleep from 0:00 p.m. to 3:00 a.m. during the first test period of 7 days, and then the following 7 days was washing-out period to ensure a complete recovery. In the second 7-day test period, participants in this group only sleep from 3:00 a.m. to 6:00 a.m. The total program lasted therefore 21 days. Group II had the same sleep deprivation (SD) but in reverse order. Each test period of sleep deprivation included the first day of normal sleep, then four days of sleep deprivation and 2 days of sleep recovery. During the 7-day test, overnight studies of polysomnogram (PSG), continuous analysis of sleep process and sleep architecture were performed. Blood and cortisol samples were collected at 7:00 a.m. during mornings of 2, 3, 4, 5, 6, 7 day. State-trait anxiety inventory (STAI), psychoomotor vigilance task (PVT) and other cognitive performance were tested during noons of 2, 3, 4, 5, 6, 7.Results: (1) With the extension of deprivation time after sleep deprivation, the decrease of S2%, the increase of both S3% and S4%, the differentiation of REM sleep and lessening of L-REM (mean, P<0.05) were observed. Comparing the data collected during sleep deprivation at different time, REM and L-REM have significant differences (P<0.01). All these changes reached their maximum at the 4th day during test periods. (2) The cortisol concentration was decreased during all sleep deprivation and the lowest concentration was achieved at the 4th day of sleep deprivation(P<0.05). (3) The tests on cognitive performance showed that sleep deprivation impaired memory, operation ability and attention(P<0.05). The drops of attention were more obvious during sleep group from 12:00 p.m. to 3:00 a.m. than that from 3:00 a.m. to 6:00 a.m(P<0.05). (4) Sleep deprivation also caused anxiety(P<0.05).Conclusions: Partial sleep deprivation has negative effects on human, increasing SWS and anxiety, and decreasing cognitive performance and cortisol concentration. All these changes reach maximum at the 4th day of sleep deprivation. Sleep deprivation from 12:00 p.m. to 3:00 a.m. has a stronger effect on cognitive performance than that from 3:00 a.m. to 6:00 a.m., but weaker effects on cortisol concentration and Immunity function. All performances can be recovered after short-term partial sleep deprivation by 2-day recovery sleep.