There are three types of abnormal blood pressure responses during exercise: hypotensive reaction, inadequate rise in blood pressure, and hypertensive reaction. At rest, an abnormal high blood pressure has an adverse prognostic implication. This is not true for a low blood pressure at rest. During exercise, however, the contrary is observed: an inadequate rise or even a fall in blood pressure below resting values indicates a significantly increased risk for cardiac events, whereas a hypertensive reaction in patients with a normal resting blood pressure has no adverse prognostic implications.