The effects of age, activity status, and blood pressure on systolic time intervals (ST1), including electromechanical systole (QS2), left ventricular ejection time (LEVT), pre-ejection period (PEP), and their heart rate-corrected indices, QS21, LEVT1, and PEP1, were analyzed in 315 male subjects aged 20-89 years. An elevated diastolic blood pressure (≥ 90 mm Hg) was significantly correlated with prolongation of the PEP, PEP1 and QS21. An elevated systolic blood pressure (≥ 140 mm Hg) was significantly correlated with prolongation of the LEVT, LEVTI, QS2, and QS21. Neither coronary heart disease, functional class 1 (67 subjects), nor estimated daily physical activity (range 1623-5752 cal/24 hours) were significantly related to ST1. In 218 healthy normotensive subjects, a significant but small prolongation of the pep and pepi (4 msec/decade) and QS21 (5 msec/decade) was found from the 3rd through the 6th decade with a decline in these intervals in the 7th and 8th decades. An interpretation of these findings is offered.