HEART-RATE-VARIABILITY IN HEALTH AND DISEASE

Beat-to-beat fluctuations in heart rate (HR) or instantaneous HR is ma inly determined by activity of the cardiac sympathetic and parasympath etic systems. Despite the need for standardization in methodology to f acilitate the interpretation and comparison of results, the data prese nted in this review clearly show that there are individual differences in heart rate variability (HRV) and that these differences partly ref lect differences in the degree of parasympathetic and sympathetic stim ulation of the heart. HRV and its spectral components can be easily an d noninvasively assessed and can provide valuable information to the o ccupational physician. Measurements of HRV and the quantification of i ts spectral components are powerful predictors of cardiovascular morbi dity and mortality. Therefore it may help assess the return to work of patients with ischemic heart disease. Studies in the workplace can al so indicate the effects of various stresses of the work environment on such patients and even on asymptomatic workers.