Blood pressure regulation during exercise.

This brief review examines five problems concerning arterial blood pressure regulation during exercise. These are: 1. A history and summary of evidence that baroreflexes are, or are not, active during exercise. 2. What might be other "regulators" of blood pressure during exercise? The characteristics of a blood pressure-raising reflex from ischemic and active skeletal muscle (muscle chemoreflex) is reviewed along with a putative role for centrally generated motor command signals (central command). 3. How blood pressure is maintained during exercise. The importance of regional vasoconstriction, particularly in active skeletal muscle, is reviewed. 4. How well matched are cardiac output and total vascular conductance? Does demand for muscle blood flow outstrip cardiac pumping capacity? 5. Reflex control of blood pressure by both baroreflexes and muscle chemoreflexes. The importance of baroreflexes and evidence for resetting is reviewed. A new hypothesis is stated.