[Effect of 12-hour work shifts of dispatchers of electric networks on their cardiovascular systems].

Blood pressure, heart rate and haemodynamics parameters in dispatchers of electric networks were studied in productive conditions under two days rotation of 12-hour shifts (17 subjects, 1224 subject-observations). It was revealed, that taking and giving periods of the shifts activate cardiovascular system work to the pronounced extent (significant increase of blood pressure at the beginning and in the end of the shifts and heart rate--at the beginning of the shifts). That is accompanied with unfavourable changes of bloodcirculation selfregulation (BCS): Predominantly heart BCS that is forming at the beginning of the shifts, especially in the evening, gradually convert towards the mainly vascular one, that is especially pronounced after 8 hours of continuous working in the day shifts. Significant predominance of the vascular BCS is noted during second consecutive day shifts, predominance of the heart BCS is noted during second consecutive night shifts. This evidences the difficulty of the second consecutive 12-hour shifts to be maintained from the cardiovascular system. Breaking of BCS, that is repeated systematically, can promote forming of the steady unfavourable changes of dispatchers' cardiovascular system state.