title: Twenty-four-hour blood pressure is not dependent on endogenous circadian rhythm.
abstract: The effects of shifted working and sleeping phases on the diurnal blood pressure rhythm were investigated in 15 physically working industrial shift workers at a slowly rotated three-shift system. Ambulatory 24-h blood pressure monitoring was performed during the morning and night shifts. In the two shifts the mean 24-h blood pressure was identical. There were no differences in the blood pressure levels in the sleeping phases or in the working periods between the two 24-h cycles. Diurnal blood pressure fluctuations had equal amplitudes. Corresponding to the lag between the working period there was a phase difference of 8 h between the 24-h blood pressure curves. At this lag, there was a high correlation between the mean hourly blood pressure values (r = 0.683). Twenty-four-hour blood pressure curves during the first and last day of a night shift were nearly equal. Thus the effects of shift rotation on the 24-h blood pressure profile were fully expressed within the first 24 hours. The immediate and complete adaptation of the 24-h blood pressure curve to shifted activity and sleeping phases indicates that activity determines the diurnal blood pressure profile. The blood pressure is largely independent of internal circadian rhythm.
authors.affiliation: Medizinische Poliklinik, University of Münster, Federal Republic of Germany.
authors.forename: P
authors.initials: P
authors.lastname: Baumgart
authors.forename: P
authors.initials: P
authors.lastname: Walger
authors.forename: G
authors.initials: G
authors.lastname: Fuchs
authors.forename: K G
authors.initials: KG
authors.lastname: Dorst
authors.forename: H
authors.initials: H
authors.lastname: Vetter
authors.forename: K H
authors.initials: KH
authors.lastname: Rahn
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D001794:Blood Pressure; D001795:Blood Pressure Determination; D002940:Circadian Rhythm; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010561:Personnel Staffing and Scheduling; D012890:Sleep / Q000502:physiology; D014937:Work