To evaluate the accuracy of continuous non-invasive blood pressure measurements in the finger during exercise, Finapres blood pressures of six normotensive healthy males were measured during increasing levels of bicycle exercise, using simultaneously registered ipsilateral intrabrachial artery pressures as a reference. At rest, finger systolic blood pressure was higher and finger diastolic and mean arterial pressures were lower than the corresponding intrabrachial pressures in five of the six subjects. During exercise, average finger diastolic and mean arterial pressures did not differ further from these intrabrachial pressures, but finger systolic pressure increased considerably more than the direct systolic pressure, exceeding it by 26 +/- 20 mmHg (mean +/- s.d.) at maximal exercise. This latter finding potentially limits the use of finger blood pressure measurements during exercise.