Performance of artillery teams in simulated sustained combat was studied. The Field Artillery Fire Direction Center (FDC) was selected as a model team for study. Standard scenario mission demands (MD) consisted of unplanned missions, preplanning, prioritizing, on call missions, revising, updating, multiple session sequences, position reports, lulls, and nonstandard missions. Each MD required either immediate and/or delayed actions. Major duties of radio telephone operator (RTO), horizontal control operator (HCO), vertical control operator (VCO), computer (COM), and fire direction officer (FDO) were assigned for each MD. Two experimental designs were utilized. Design-I had a single 86 hour operational challenge, design-II had two 38 hour challenges separated by a 34 hour rest. Design-I was open ended since 86 hours exceeded limits for sleep deprived subjects. FDC teams included five 18 to 24 years old males. Each subject was equipped with radio transmitter, physiological cassette recorder, wrist actograph, electrocardiograph, and in some instances electroencephalograph electrodes. Teams spent 6 hours in scenario epoch in the simulation facility. All teams responded to competitive challenges and became involved with simulation. Team one withdrew after 48 hours and team four after 45 hours. Teams two and three completed both 38 hour challenges. Accuracy of firing data for unplanned missions was well maintained by all teams, however timeliness suffered in all but one team. All teams showed increased efficiency after pretraining. Preplanned target processing was less adequate at 36 hours for teams one and four than for teams two and three. Results of physical and medical tests indicated reduced physical aerobic endurance. The authors state that the study supports the expectation that well trained manual FDC teams could function effectively in high task load situations for 38 hours without sleep.
The Twenty-Four Hour Workday: Proceedings of a Symposium on Variations in Work-Sleep Schedules, Division of Biomedical and Behavioral Science, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, DHHS (NIOSH) Publication No. 81-127