Factors affecting ambulatory heart rate in industrial workers†

The influence of several factors on the heart-rate (HR) response to tasks performed during regular work has been evaluated in a study population of 1654 male factory employees in Israel. Each worker was monitored for approximately one hour with an ambulatory electrocardiogram. The percentage change from resting HR decreased with increasing age and, as expected, was lower in sedentary workers than in manual workers. A highly significant negative correlation between the HR response and both systolic and diastolic blood pressure was found in the manual workers only. In further multiple regression analysis, after controlling for age, relative weight, smoking status, resting HR and the presence of abnormalities on the resting ECG, the association persisted for systolic BP only. Among young workers, both smoking and relative body weight were significantly associated with a higher HR response to work. Those with ECG abnormalities had lower HR response than those with normal ECGs, but not significantly so. These findings indicate that for roughly equivalent tasks and levels of resting HR, the HR response to regular work is influenced by several constitutional and behavioural factors. It may therefore be important to consider these factors when assigning workers to tasks involving strenuous effort.