[Participation of mental workload in circulatory system reaction to occupational work]

The aim of the study was to determine the degree to which the heart rate during and after work of variable physical and mental load was affected by the mental workload of moderate intensity. The subjects were 150 women aged 17-57. 24-hour recordings of their heart rates during work, leisure and sleep were taken using the Medilog recording-analysing system. Mental workload was determined in two ways: by the AET method, which enabled objective evaluation of the load, and by a method which involved subjective evaluation of work requirements and the ability to cope with them. Using the multiple regression analysis, the degree to which concurrent elements of mental and physical workload an serve as predictors of heart rate during work, leisure and sleep. The results show that physical workload is the more essential factor affecting the reaction of the circulatory system under the circumstances of concurrent mental and physical workload. By extending the measurements to involve off-duty hours, it was possible to determine that the consequences of mental workload manifested also after the work. The prolonged effect of mental workload on the heart rate was evident only when the subjective method of workload estimation was used. This points to the individual character of mental workload. The findings indicate on one hand that the share of mental workload should not be neglected during evaluation of the effects of occupational workload on the physiological reactions and, on the other, that the heart rate measurement is a useful tool for indicating essential elements of workload.