Cardiovascular control during whole body exercise.
It has been considered whether during whole body exercise the increase in cardiac output is large enough to support skeletal muscle blood flow. This review addresses four lines of evidence for a flow limitation to skeletal muscles during whole body exercise. First, even though during exercise the blood flow achieved by the arms is lower than that achieved by the legs (∼160 vs. ∼385 ml·min(-1)·100 g(-1)), the muscle mass that can be perfused with such flow is limited by the capacity to increase cardiac output (42 l/min, highest recorded value). Secondly, activation of the exercise pressor reflex during fatiguing work with one muscle group limits flow to other muscle groups. Another line of evidence comes from evaluation of regional blood flow during exercise where there is a discrepancy between flow to a muscle group when it is working exclusively and when it works together with other muscles. Finally, regulation of peripheral resistance by sympathetic vasoconstriction in active muscles by the arterial baroreflex is critical for blood pressure regulation during exercise. Together, these findings indicate that during whole body exercise muscle blood flow is subordinate to the control of blood pressure.
Department of Health Science and Technology, Aalborg University, Aalborg, Denmark; and svolian@hst.aau.dk.
Stefanos
S
Volianitis
The Copenhagen Muscle Research Center, Department of Anesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
Niels H
NH
Secher
D017704:Baroreflex / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology; D003198:Computer Simulation; D015444:Exercise / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000098:blood supply / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology
arm exercise; baroreflex; blood pressure; cerebral blood flow; muscle blood flow