Diurnal variations of blood pressure in shift workers during day and night shifts

Abstract

The dependence of blood pressure upon internal rhythms and the short-term effects of shift rota on the blood pressure were investigated in shift workers. Blood pressure was measured every 30 min using automatic records for 24h in 17 physically working men in a chemical factory during their morning and night shifts. There were no differences of the mean blood pressure between the respective sleeping phases or between the working periods. The amplitudes of circadian blood pressure variations were equal. There was a phase difference of 8h corresponding to the lag between the working periods. At this 8-h lag the hourly means of the 24-h blood pressure were closely correlated (r=0.69). Comparisons of 24-h blood pressure profiles during the first and last days of night shift week showed that the effects of night work on the blood pressure were already fully developed within the first 24h (r=0.86). Thus the diurnal variations of the blood pressure are determined by the working and sleeping periods and largely independent of endogenous rhythm. There is no short-term alteration of the mean 24-h blood pressure after shift rota.

Relationship between shift work and onset of hypertension in a cohort of manual workers

“…Some studies on the ambulatory measurement of blood pressure among shift workers indicate that the elevation of blood pressure among shift and night workers is caused by differences in the diurnal-nocturnal blood pressure rhythm and that it does not always cause definite hypertension (21)(22)(23)(24)(25). Our results suggested a chronic effect on the blood pressure of shift workers.…”

“…The participants were classified into 1 of 4 groups according to work conditions in 1990 and 1995: (i) "day-day" workers, men who did day work in both 1990 and 1995, (ii) "day-shift" workers, men who did day work in 1990 and transferred to rotating 3-shift work We analyzed data by 3 age groups (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39), and 4 0 4 9 years). The cumulative incidence of hypertension during the 5-year period was compared between the 4 groups according to their work conditions.…”