Accession Number : ADA306497

Title :   Submarines and 18-Hour Work Shift Work Schedules,

Corporate Author : NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA

Personal Author(s) : Kelly, Tamsin L. ; Grill, Jeffrey T. ; Hunt, Phillip D. ; Neri, David F.

PDF Url : ADA306497

Report Date : FEB 1996

Pagination or Media Count : 35

Abstract : Circadian rhythms are fluctuations in physiological and behavioral parameters, cycling at a rate of about once every 24 hr, which are controlled by a biological clock. The endogenous circadian clock has been shown to cycle at a rate (tau) unique to each individual that is generally longer than 24 hr (24.25-25 hr). The most accurate method for determining tau is a laboratory protocol called forced desynchrony. In forced desynchrony, subjects are isolated from time cues and bright light. The sleep-wake schedule is lengthened or shortened to the point that it is physiologically impossible for a person to synchronize with. Under these conditions, circadian rhythm free run at the cycle length of the endogenous clock. The submarine 6-on/i 2-off schedule is very similar to such protocols, requiring subjects to live by an 1 8-hr day under conditions of isolation from bright light. A study of personnel living on this schedule aboard a submarine was completed. Measures included the circadian rhythm of salivary melatonin, sleep logs, actigraphs, and a performance assessment battery (PAB) administered on hand-held computers. Preliminary results from the PAB, the sleep logs, and the actigraphs are presented. Subjects appear to get sufficient sleep and to maintain acceptable performance levels on this work schedule.

Descriptors :   *CIRCADIAN RHYTHMS, *PHYSIOLOGY, *BEHAVIOR, *SLEEP DEPRIVATION, *SUBMARINES, *SLEEP, BIOLOGY, CLOCKS, COMPUTERS, PARAMETERS, LIGHT, ISOLATION, ACCURACY, CYCLES, REDUCTION, BRIGHTNESS, SCHEDULING, LENGTH, PERSONNEL, RECORDS, HAND HELD, SALIVA, MELATONIN.

Subject Categories : Anatomy and Physiology
      Psychology
      Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE