A 14-h night-shift in the control room of a fire brigade

Abstract

All 29 operators in the control room of a fire brigade performed test sessions during work and leisure time at 2-h intervals on a day with a 14-h night-shift, a day off and a day with a 10-h morning shift. The test sessions consisted of a visual search choice reaction time test and two Sternberg memory search tests (1 or 5 letters had to be memorized). Furthermore, the operators recorded their oral temperature and their subjective alertness before each test session. The subject also kept a diary of work and sleep times for 14 days. The circadian rhythm of body temperature was hardly changed by a single night-shift. Parallel to the body temperature, the subjective alertness fell significantly during the night-shift reaching a minimum value at 06:00 h. The mean reaction times increased non-significantly at the end of the night-shift and the results of the two Sternberg memory search tests showed no significant trends. The sleep of the operators after the night-shift was on average reduced to 5 hs 34 min. The results of subjective rating of alertness and reaction time test are interpreted as effects of the combined influences of circadian rhythmicity, sleep loss and time on professional task. Most results support the conclusion that a 14-h night-shift without extensive breaks is not acceptable.

Effects of Major Depression on Moment-in-Time Work Performance

“…This finding is consistent with a diurnal pattern of greater symptom severity later in the day that is often found among patients with the milder forms of depression likely to be found in working populations (44). It is also possible that depression exacerbates the fatigue and reduction in cognitive abilities that have been found to increase naturally over the workday (45)(46)(47)(48).…”

Long Shifts, Short Rests and Vulnerability to Shift Work

“…In a study of control room workers, Knauth and co-workers concluded that a shift system with 10h D-shifts followed by a single 14h N-shift was unacceptable (Knauth et al, 1995). However, the schedule was popular amongst the workers and performance was not significantly affected.…”