The muscle pump indeed raises muscle blood flow during locomotion.

POINT-COUNTERPOINT COMMENTSThe muscle pump indeed raises muscle blood flow during locomotion.Carl F. RotheCarl F. RothePublished Online:01 Aug 2005https://doi.org/10.1152/japplphysiol.00602.2005MoreSectionsPDF (32 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations This letter is in response to the Point-Counterpoint series “The muscle pump is/is not an important determinant of muscle blood flow during exercise” that appeared in the July issue (vol. 99: 371–375, 2005; doi:10.1152/japplphysiol.00381; http://jap.physiology.org/content/vol99/issue1).Letter to Editor: Because well-trained running humans can develop cardiac outputs of 35 l/min with heart rates of 190 beats/min and stroke volumes increased to 189 ml (2), Clifford et al. (1), in their rebuttal, should have explained how vasodilatation, without a muscle pump, could account for such high flows through the active skeletal muscle. They should not have been so cavalier in declaring that “ ‘The emperor has no clothes'—the muscle pump is not an important determinate of muscle blood flow during exercise.” Laughlin and Joyner (3), in a 2003 Invited Editorial, stated, “It is possible that the muscle pump is of greatest importance in perfusion of active skeletal muscle in dependent limbs of humans.”Clifford et al. (1) also state, “By definition, the muscle pump can only influence blood flow for as long as venous pressure is reduced.” This unsupported definition does not apply to a pumping system that would increase the downstream venous pressure to increase right ventricular end diastolic volume and then stroke volume and cardiac output. There is a reason that venous valves evolved. As a corollary, atrial contraction increases flow into the ventricle near the end of diastole to increase the end diastolic volume to increase cardiac output. Their function is also minor during normal activity but becomes important during strenuous exercise. My Cardiovascular Interactions Project includes a six-compartment, closed-circuit mathematical model that helps understand the complex interactions between the heart and peripheral circulation during exercise (4). The muscle pump indeed raises muscle blood flow during locomotion.REFERENCES1 Clifford PS, Hamann JJ, Valic Z, and Buckwalter JB. The muscle pump is not an important determinant of muscle blood flow during exercise. J Appl Physiol 99: 371–375, 2005.Link | ISI | Google Scholar2 Ekblom B and Hermansen L. Cardiac output in athletes. J Appl Physiol 25: 619–625, 1968.Link | ISI | Google Scholar3 Laughlin MH and Joyner M. Closer to the edge? Contractions, pressures, waterfalls, and blood flow to contracting skeletal muscle. J Appl Physiol 94: 3–5, 2003.Link | ISI | Google Scholar4 Rothe CF and Gersting JM J. Cardiovascular interactions: an interactive tutorial and mathematical model. Adv Physiol Educ 26: 98–108, 2002.Link | ISI | Google Scholar Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByMagnetorheological composites for biomedical applicationsCardiovascular Response During Exercise28 November 2019Tunable Properties of Magnetoactive Elastomers for Biomedical ApplicationsPhysics Procedia, Vol. 82Cardiovascular Response During Exercise8 July 2013Soft Iron/Silicon Composite Tubes for Magnetic Peristaltic Pumping: Frequency-Dependent Pressure and Volume Flow6 March 2013 | Advanced Functional Materials, Vol. 23, No. 31Gender comparison of psychophysical forces, cardiopulmonary, and muscle metabolic responses during a simulated cart pushing taskGait & Posture, Vol. 32, No. 4Psychophysiological Responses in Women During Cart Pushing on Different Frictional Walkways19 November 2009 | Human Factors: The Journal of the Human Factors and Ergonomics Society, Vol. 51, No. 5Haemodynamic responses to exercise, ATP infusion and thigh compression in humans: insight into the role of muscle mechanisms on cardiovascular function1 May 2008 | The Journal of Physiology, Vol. 586, No. 9 More from this issue > Volume 99Issue 2August 2005Pages 773-773 Copyright & PermissionsCopyright © 2005 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00602.2005PubMed16020443History Published online 1 August 2005 Published in print 1 August 2005 Metrics