Performance, mood, and clinical symptoms in men exposed to prolonged, severe physical work and sleep deprivation.

There were 44 young men who participated in strenuous combat courses of 4 d (course I) or 5 d (course II), almost without sleep. They were tested and examined clinically each morning. Groups 1 and 2 had no organized sleep, whereas groups 3 and 4 got 3 and 6 h, respectively, in the middle of each course. Substantial impairment was observed in all tests, as well as clinical symptoms toward the end of the courses for groups 1 and 2. In the vigilance test, the reaction time task, the code test, and the profile of mood-state, significant impairment was observed even after 24 h. Complaints of symptoms came first. Disturbance of senses and behaviour appeared later. Group 4 had significantly better results than groups 1 and 2 in clinical symptoms and all tests, except the positive score in mood-state. Group 3 occupied an intermediate position. Corresponding results were obtained in the two separate courses. In the morning following the course, recovery after 4 h of sleep was less extensive for courses II than course I participants.