DEFENCE AND CIVIL INST OF ENVIRONMENTAL MEDICINE DOWNSVIEW (ONTARIO)
The effect of sleep deprivation and physical fatigue on self-paced work output was determined in two sustained combat engineer operations. In the first Ripe Sapper, four subjects from 2 Combat Engineer Regiment went without sleep for 690 hours. During this period they performed only four physically demanding tasks, three of them in the last 24 hours. Continuous recordings of heart rate HR indicated that sleep deprivation, in the absence of physical fatigue, had no effect on work intensity and the workrecovery cycle. In the second sustained operation Longue Journee, six subjects from 5 Combat Engineer Regiment carried out a full schedule of physically demanding tasks during a period of sleep deprivation lasting 47 hours. Some of the tasks were repeated at least once so that the effects of sleep loss and physical fatigue could be assessed. For the first 14 hours of Longue Journee, the subjects worked for shorter periods and took longer rests. Rating scales confirmed that these changes coincided with the development of physical fatigue. Since sleep deprivation was without effect in Ripe Sapper, the decline in self-paced work output in Longue Journee was attributed to physical fatigue.