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The Military Performance of Soldiers in Continuous Operations: Exercises "Early Call" I and II.

NIOSH 1981 Jul:549-579
Effects of sleep loss on performance of soldiers in defensive positions were studied. The test group in Exercise Early Call-I consisted of 36 young infantrymen. The trial was divided into five exercises. Exercises one and five were controls with 6 hours of sleep in the field. The sleep schedule in three other platoons was zero (P0), 1.5 (P1.5), and 3 (P3) hours per day. The 9 day sleep deprivation period consisted of a 3 day stay in three defensive positions at locations where common military activities were performed. The trial was carried out in cool wet weather. Weapon handling, shooting, cognitive functioning, and physical fitness were assessed daily. Physiological and biomedical tests were performed. Subjective measures included self rating and observer assessment. All of P0 troop withdrew by day four and 39 percent of P1.5 platoon left by day five. Forty eight percent of the latter and 91 percent of P3 platoon completed the exercise. Results showed that shooting skill did not deteriorate, but vigilance did. Motivation appeared to be an important factor. Observers considered that physical tasks were performed at an acceptable level by P0 platoon for 3 days, by P1.5 for 6 days, and by P3 platoon for 9 days. Design of Early Call- II consisted of 3.75 days of continuous activity followed by 6 days with limited opportunity for sleep. There was no scheduled sleep during the first 90 hours and 4 hours sleep in every 24 hours for the next 6 days. The trial was designed as a tactical exercise at various ranges and test sites involving traveling 26 miles per day during winter. All ten subjects completed the trial. Their effectiveness was impaired by day two and improved with 4 hours sleep. The author concludes that effects of sleep loss are psychological, small amounts of sleep are beneficial, sleep deprivation results in likelihood of physiological sleep pattern development in the brain, and that hostile climates interact with sleep loss and influence survival times.
Sleep-deprivation; Military-personnel; Endurance-tests; Work-capability; Work-performance; Physiological-testing; Mental-fatigue; Physical-stress;
Publication Date
Document Type
Conference/Symposia Proceedings;
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
(NIOSH) 81-127
NIOSH Division
Source Name
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