EFFECTS OF SHIFT WORK ON CARDIOVASCULAR ACTIVITY, SERUM CORTISOL AND WHITE BLOOD CELL COUNT IN A GROUP OF ITALIAN FISHERMEN

We analyzed the effects of working activity and working shifts on the circadian rhythmicity and circadian phase relations of serum cortisol level, white blood cell count, resting heart rate and systolic/diastolic blood pressure in a group of Italian fishermen. We observed a shift-induced displacement of cortisol secretion and a change in leukocyte count. Moreover, systolic/diastolic blood pressure and resting heart rate were markedly influenced by the night shift, whereas no appreciable changes were observed after the morning and afternoon shifts, compared to pre-working values. These data suggest that the human circadian system is greatly influenced by shift work, and that serum cortisol level, leukocyte count, systolic and diastolic blood pressure as well as resting heart rate are sensitive indicators of the biological responses to a stress workload in shift workers, especially after a night shift