title: The effect of high ambient temperature on the adjustment of operators to fast rotating 12-hour shiftwork.
abstract: The aim of the investigation was to study the effect of high ambient temperature (HAT) on the adjustment to fast rotating 12-h shifts by following the time-of-day variations of certain circadian and stress indicators. We investigated 12 male HAT operators and 21 individuals working in normal ambient temperature (NAT) in a thermoelectric power plant. The shift system of both groups comprised an 8-day cycle of 2 shifts per day (day shift: 0700 to 1900; night shift: 1900 to 0700), with 2 successive days of the same shift followed by 2 days off. We followed variations in oral temperature, 11-oxycorticoids, as well as catecholamines adrenaline and noradrenaline excretion at 4-h intervals during 2 day and 2 night shifts. Our data show daily oriented circadian rhythms of operators working on fast rotating 12-h shifts in conditions of HAT and NAT. Reduced general activation was observed in the second half of the prolonged 12-h night shifts, more pronounced in HAT operators. The stress indicators investigated here showed a stress reaction in HAT operators at the beginning of the first day shift. Both prolonged 12-h shifts and high ambient temperature impose extra demands and may have an impact on the performance and work safety of the operators.
authors.affiliation: Department of Physiology, Psychology and Ergonomics, National Center of Hygiene, Medical Ecology and Nutrition, 15 Dimiter Nestorov Boul., 1431 Sofia, Bulgaria.
authors.forename: K K
authors.initials: KK
authors.lastname: Vangelova
authors.forename: C E
authors.initials: CE
authors.lastname: Deyanov
mesh_terms: D000305:Adrenal Cortex Hormones / Q000652:urine; D000328:Adult; D000704:Analysis of Variance; D001831:Body Temperature; D002940:Circadian Rhythm; D004837:Epinephrine / Q000652:urine; D018882:Heat Stress Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008297:Male; D009638:Norepinephrine / Q000652:urine; D016273:Occupational Exposure; D011210:Power Plants; D013997:Time Factors
chemical_list: D000305:Adrenal Cortex Hormones; D009638:Norepinephrine; D004837:Epinephrine