Arterial pressure and shift work activities

: Circadian blood pressure (BP) and heart rate (HR) variations are studied during activities and sleep in a group of nine subjects with shiftwork activities (3 X 8 hours with a short rotation of 2 days). BP and HR values are measured in ambulatory (outside the hospital) with and automatic device (Spacelab system 5,200) during 24 hours at 3 times according to the work periods (morning 7-12 AM, afternoon 3-11 PM, night 1-7 AM) on a month. According to BP hour variations, activities and sleep are the main determining factors. For work periods BP mean values are significantly lower during night than during day. The lower BP values are found during the sleep periods, but the values are higher when subjects sleep during the day. There is an adaptation according to work hour changes, but this adaptation is incomplete and during night activities, the circadian rythm is partly altered. These constatations must be taken in account particularly on a therapeutic point of view for hypertensive subjects for which the treatment must be adjusted.