Submarines and 18-Hour Work Shift Work Schedules,
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1996
- Accession Number
- ADA306497
Entities
People
- David F. Neri
- Jeffrey T. Grill
- Phillip D. Hunt
- Tamsin L. Kelly
Organizations
- Naval Health Research Center