Circadian Temperature Rhythm Amplitude and Long Term Tolerance of Shiftworking.
Reinberg-A; Andlauer-P; Vieux-N
NIOSH 1981 Jul:87-103
The amplitude of body temperature circadian rhythm was assessed as an index for prediction of longterm tolerance of shiftwork schedules. Body temperature was studied to determine whether rapid adjustment of acrophase (Ap) to phase shift of socioecological synchronizers (SESs) was associated with small circadian amplitude and to assess whether good clinical tolerance of shiftwork was related to large amplitude of oral temperature circadian rhythm. One study used 25 male shiftworkers in two French oil refineries who had been on shiftwork from 1 to 16 years. One group (age range 24 to 48 years) was on weekly rotations. Another group (age range 21 to 28 years) was on rapid rotations of 3 to 4 days. Self measurements of oral temperature, grip strength, and peak expiratory flow were performed every 4 hours except during sleep over a period of 6 to 8 weeks. Negative correlations were established between amplitude of circadian rhythm and Ap shift for oral temperature, peak expiratory flow, and urinary 17-hydroxycorticosterone. Another study involved 48 shiftworkers in French steel and chemical plants. Steel workers were on a 7 day rotation, and chemical operators rotated every 2 days. Clinical tolerance of shiftwork was assessed by incidence and intensity of digestive, neurological, and sleep disturbances. Significant differences between tolerant and nontolerant shiftworkers were noted only for amplitude. Small circadian amplitude was associated with poor tolerance. Another study considered the relationship between amplitude, shiftwork tolerance, and age using 29 oil refinery operators on rapidly rotating shifts. Oral temperature was measured every 4 hours except during sleep, and a 3 week longitudinal series was obtained for each individual. A negative correlation was noted for amplitude and Ap shift for oral temperature. Cosinor analysis indicated that only temperature circadian amplitude differed between shift tolerant and nontolerant subjects. The authors conclude that rapidly rotating shifts encourage development of long term tolerance to shiftwork associated with large amplitude and slow adjustment in circadian temperature rhythm.
Worker-health; Work-performance; Sleep-deprivation; Work-intervals; Job-stress; Physiological-response; Worker-motivation; Psychological-effects; Biological-rhythms;
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