Sustained operations and military performance

A militarily realistic schedule is one that demands several days with only very limited opportunities for sleep, followed by several days without any opportunity for sleep. A trial was carried out to study the effects of total sleep deprivation following partial sleep deprivation. Twelve infantry soldiers, divided into two groups of six, took part in a 6-day trial in which the experimental group was scheduled for 1.5 h of sleep every 24 h for 3 days followed by 3 days in which no sleep was scheduled. The control group was scheduled to have 4 h of sleep every 24 h for 6 days. Following the sleep-deprivation period, unlimited sleep was permitted for both groups in a 40.25-h (1.7-day) rest period. Three of the six subjects in the experimental group completed the 152 h (6.3-day) trial; all six subjects in the control group completed the trial. On the last sleep-deprivation day, cognitive performance was 37% of the baseline value for the experimental group and 94% for the control group.