Abstract

OBJECTIVES: To evaluate coach drivers' work stress during work and in the course of recovery from work by measurement of urinary catecholamines and cortisol. METHODS: The urinary excretion rate of adrenaline, noradrenaline, and cortisol of 10 coach drivers was studied during a long distance trip of three days and two consecutive days off. Each driver was asked to provide seven urine samples on the working days and six urine samples on the days off. The second day off was considered as the baseline. RESULTS: An occupationally induced disturbance of the circadian rhythmicity was found for adrenaline and noradrenaline but not for cortisol. The mean excretion rates of adrenaline on the first working day and most samples on all working days were higher than the baseline. For both adrenaline and noradrenaline the mean excretion rates on the first day off were lower than the baseline. For cortisol, the mean excretion rate on all working days was higher than the baseline. A trend towards accumulation of cortisol excretion from the first working day to the third working day was found. A backward shift in peak concentrations was found for adrenaline and noradrenaline on the second working day, as was a forward shift in peak concentration of cortisol on both days off. CONCLUSIONS: Long distance coach drivers showed occupationally induced reactivity in rates of urinary excretion of adrenaline, noradrenaline, and cortisol. After the outward journey the rates of excretion of catecholamines did not return to baseline values. The course of recovery in adrenaline excretion after the journey showed a new phenomenon, which has been called "fatigue debt". It is recommended that longer resting times in shuttle bus trips and fixed days off after these kind of trips should be planned. Extensive future research should be focused on the additional relations between fatigue debt and health complaints.