Experimental Physiology
91.1 pp 89-102
DOI: 10.1113/expphysiol.2005.032367
© The Physiological Society 2006
The mammalian exercise pressor reflex in health and disease
Scott A Smith1,
Jere H Mitchell2,3 and
Mary G Garry2
Departments of 1 Physical Therapy2 Internal Medicine3 Physiology, Harry S. Moss Heart Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
The exercise pressor reflex (a peripheral neural reflex originating in skeletal muscle) contributes significantly to the regulation of the cardiovascular system during exercise. Exercise-induced signals that comprise the afferent arm of the reflex are generated by activation of mechanically (muscle mechanoreflex) and chemically sensitive (muscle metaboreflex) skeletal muscle receptors. Activation of these receptors and their associated afferent fibres reflexively adjusts sympathetic and parasympathetic nerve activity during exercise. In heart failure, the cardiovascular response to exercise is augmented. Owing to the peripheral skeletal myopathy that develops in heart failure (e.g. muscle atrophy, decreased peripheral blood flow, fibre-type transformation and reduced oxidative capacity), the exercise pressor reflex has been implicated as a possible mechanism by which the cardiovascular response to physical activity is exaggerated in this disease. Accumulating evidence supports this conclusion. This review therefore focuses on the role of the exercise pressor reflex in regulating the cardiovascular system during exercise in both health and disease. Updates on our current understanding of the exercise pressor reflex neural pathway as well as experimental models used to study this reflex are presented. In addition, special emphasis is placed on the changes in exercise pressor reflex activity that develop in heart failure, including the contributions of the muscle mechanoreflex and metaboreflex to this pressor reflex dysfunction.
(Received 28 September 2005;
accepted after revision 18 October 2005; first published online 10 November 2005)
Corresponding author M. G. Garry: University of Texas Southwestern Medical Center, Harry S. Moss Heart Center, Department of Internal Medicine, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9174 USA. Email: mary.garry{at}utsouthwestern.edu
Copyright © 2006 by the The Physiological Society.