Internal Desynchronization of Circadian Rhythms and Tolerance to Shift Work

摘要: Intolerance to shift work may result from individual susceptibility an internal desynchronization. Some workers (SW) who show desynchronization of their circadian rhythms (e.g., sleep-wake, body temperature, and grip strength both hands) exhibit symptoms SW intolerance, such as sleep alteration, persistent fatigue, medication dependence, mood disturbances, including depression. Existing time series data previously collected 48 male Caucasian French were reanalyzed specifically test the hypothesis that synchronization is associated with intolerance symptoms. The entry subjects into study was randomized. Three groups formed thereafter: good tolerance (n=14); poor tolerance, evident by medical complaints for at least one year (n=19); former (n=15) very had been discharged night 1.5 yr span but symptom-free study. Individual longitudinal selected variables (self-recorded sleep-wake using a log, self-measured hands Colin Gentile dynamometer, oral temperature clinical thermometer) gathered 15 days, during or two shifts. Measurements performed 4-5 times/24 h. Power spectra used quantify prominent period (tau) t-test, chi square, correlation coefficient statistical tools. mean (+/-SEM) age greater than (44.9+/-2.1 yrs vs. 40.1+/-2.6 yrs, p<.001) (very tolerance; 33.4+/-1.7, p<.001). shift-work duration (yrs) longer in (19.9+/-2.2 15.7+/-2.2; p<0.002) (10.7+/-1.2; p<.0001). between subject stronger tolerant (r=0.97, p<.0001) non-tolerant (r=0.80, p<0.001) (r=0.72, p<.01). rhythm tau 24 h all subjects. number desynchronized (tau differing h) (chi square=38.9, In Former (i.e., individuals assessed follow-up studies done 20 after return day work), reduced absent. results suggest are particularly sensitive organization.