Regular conditioning has been well documented to exert a beneficial effect on cardiovascular risk factors and to improve overall cardiovascular health and to reduce the incidence of coronary disease. There are conflicting results concerning the effect of physical exercise on blood pressure (BP) in hypertensive patients and its importance in the treatment of hypertension. Therefore 10 male patients with mild arterial hypertension were studied in order to define the BP response to long-term aerobic training (60 min twice a week) under resting conditions, during standardised ergometric workload, during isometric exercise, during cold pressor testing and during 24-h BP monitoring. After 18 months of regular training there were significant reductions in arterial pressures at rest, during and after standardised ergometry and during isometric and cold pressor testing when compared with pre-training. The heart rate also decreased significantly during exercise testing thus implying a decrease in myocardial oxygen consumption. After long-term training, a reduction in systolic and diastolic BP could also be shown during 24-h ambulatory BP monitoring. These results demonstrate that long-term aerobic training leads to a decrease in systolic and diastolic BP at rest, during exercise and during 24-h BP monitoring and imply a beneficial effect in the management of hypertension that is nearly comparable to that of drug therapy.