The assessment of blood pressure during bicycle ergometry or treadmill exercise is considered of paramount importance in establishing the eligibility of an athlete to enter competitive sports. One of the potential risks related to an exaggerated blood pressure response to stress testing is that in the long run repetitive blood pressure peaks triggered by physical activity may determine chronic target organ damage or favour the occurrence of an acute cardiovascular event. Our concern should be addressed particularly to the competitive athlete, insofar as training seems to increase the blood pressure reactivity to dynamic exercise. However, studies performed in young borderline hypertensive subjects have demonstrated that blood pressure level during steady-state long lasting exercise can not be predicted by the maximum blood pressure attained during a short-lasting incremental effort. Several prospective studies have demonstrated that excessive increases in blood pressure during exercise may be a marker of future sustained hypertension and of increased risk of cardiovascular mortality. The steeper rise in exercise blood pressure in normotensive subjects prone to develop hypertension and its complications seems to be due to a failure to reduce total peripheral resistance adequately during exercise, as a result of initial structural vascular changes which would pre-date the tonic elevation in the blood pressure.