Arterial baroreflex resetting during exercise: a current perspective

Within the past 20 years numerous animal and human experiments have provided supportive evidence of arterial baroreflex resetting during exercise. In addition, it has been demonstrated that both the feedforward mechanism of central command and the feedback mechanism associated with skeletal muscle afferents (the exercise pressor reflex) play both independent and interactive roles in the resetting of the arterial baroreflex with exercise. A fundamental alteration associated with baroreflex resetting during exercise is the movement of the operating point of the reflex away from the centring point and closer to the threshold, thereby increasing the ability of the reflex to buffer hypertensive stimuli. Recent studies suggest that central command and the cardiopulmonary baroreceptors may play a role in this movement of the operating point on the baroreflex-heart rate and baroreflex-blood pressure curve, respectively. Current research is focusing on the investigation of central neural mechanisms involved in cardiovascular control, including use of electrophysiological and molecular biological techniques in rat and mouse models to investigate baroreflex resetting as well as use of state of the art brain imaging techniques in humans. However, the purpose of this review is to describe the role of the arterial baroreflex in the regulation of arterial blood pressure during physical activity from a historical perspective with a particular emphasis on human investigations.