Effects of sleep deprivation on performance of Naval seamen: I. Total sleep deprivation on performance.

Sleep deprivation leads to impairment in performance, loss of efficiency and deterioration in mood states such as tension, depression, aggression, fatigue, confusion and vigour. These can be detrimental to combat readiness and could contribute to "battle stress". In the present study, a homogeneous group of 20 seamen under total sleep deprivation was rated 6 hourly with the Stanford Sleepiness Scale (SSS), Profile of Mood States (POMS) and a battery of performance tests including the trail making, grooved peg board, digit span, digit symbol, sea-shore rhythm, flicker fusion, dynamometer and naval tasks. With the exception of the trail making test and naval tasks, the test performance was observed to correlate significantly (P < 0.05) with the SSS. A higher sleepiness score was associated with a poorer performance in test scores. On the time trends of sleep deprivation on the performance tests measured, a dip in performance was observed in all the tests at 42 hours of sleep deprivation and continuous deterioration of performance was observed after 72 hours of sleep deprivation. The cognitive, vigilance, mood and sleepiness tests were substantially affected by sleep deprivation. Greater effect was observed in tests that involved cognition, speed and precision and smaller effect was observed in routine tasks that involved gross manual movement. The decrease in performance observed at 42 hours of sleep deprivation was 5.9 standard deviation from initial values for SSS; 3.9 for sea-shore rhythm, 3.0 for grooved peg board; 2.6 for dynamometer; 2.4 for mood; 1.8 for digit span; 1.6 for trail making and digit symbol; 1.0 for naval tasks and addition; and 0.9 for flicker fusion.(ABSTRACT TRUNCATED AT 250 WORDS)