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BioMed Research International
Volume 2013 (2013), Article ID 893506, 18 pages
http://dx.doi.org/10.1155/2013/893506
Review Article

Evaluating the Importance of the Carotid Chemoreceptors in Controlling Breathing during Exercise in Man

School of Sport, Exercise & Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK

Received 25 April 2013; Accepted 8 July 2013

Academic Editor: Maxime Cannesson

Copyright © 2013 M. J. Parkes. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Only the carotid chemoreceptors stimulate breathing during hypoxia in Man. They are also ideally located to warn if the brain’s oxygen supply falls, or if hypercapnia occurs. Since their discovery ~80 years ago stimulation, ablation, and recording experiments still leave 3 substantial difficulties in establishing how important the carotid chemoreceptors are in controlling breathing during exercise in Man: (i) they are in the wrong location to measure metabolic rate (but are ideally located to measure any mismatch), (ii) they receive no known signal during exercise linking them with metabolic rate and no overt mismatch signals occur and (iii) their denervation in Man fails to prevent breathing matching metabolic rate in exercise. New research is needed to enable recording from carotid chemoreceptors in Man to establish whether there is any factor that rises with metabolic rate and greatly increases carotid chemoreceptor activity during exercise. Available evidence so far in Man indicates that carotid chemoreceptors are either one of two mechanisms that explain breathing matching metabolic rate or have no importance. We still lack key experimental evidence to distinguish between these two possibilities.