Orthostatic-induced Hypotension Attenuates Cold Pressor Pain Perception

In recent years, numerous studies have established a connection between blood pressure and nocioception. While this connection is well documented in the literature, its underlying physiological mechanisms have yet to be elucidated. Much attention has focused on the relationship between cardiovascular regulatory centers and nocioception, yet the intricacies of this relationship have not been fully explored. Therefore, the purpose of this investigation was to examine the role of the baroreflex system as a modulator of pain perception. Twenty normotensive males participated in two laboratory sessions. Time to cold pain threshold and pain tolerance was measured at rest during the first visit. On visit two, blood pressure was orthostatically manipulated via tilt table at postures 90o, 120o, and 180o. Orthostatic manipulation significantly lowered systolic blood pressure (SBP), pain threshold, and pain tolerance from seated baseline at 120o and 180o. The regression models for baroreceptor reflex sensitivity (BRS) assessed during seated baseline and at 120o and 180o revealed a significant negative beta weight for the effect of SBP. A significant negative beta weight for the effects of BRS, SBP, and their interaction was observed at 90o. In conclusion, orthostatic baroreceptor activation appears to exert an inhibitory effect on the brain that decreases pain sensitivity. This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/healthfac/32 Orthostatic Hypotension and Pain Perception 21 Journal of Exercise Physiologyonline (JEPonline) Volume 13 Number 1 February 2010 Managing Editor Tommy Boone, PhD, MPH Editor-in-Chief Jon K. Linderman, PhD Review Board Todd Astorino, PhD Julien Baker, PhD Tommy Boone, PhD Eric Goulet, PhD Robert Gotshall, PhD Alexander Hutchison, PhD M. Knight-Maloney, PhD Len Kravitz, PhD James Laskin, PhD Derek Marks, PhD Cristine Mermier, PhD Chantal Vella, PhD Ben Zhou, PhD Official Research Journal of the American Society of Exercise Physiologists (ASEP) ISSN 1097-975 Systems Physiology Cardiopulmonary Orthostatic-induced Hypotension Attenuates Cold Pressor Pain Perception KAREN WONDERS and DANIEL DRURY Wright State University, Department of Health, Physical Education and Recreation, Dayton, OH 45435 USA, Gettysburg College, Department of Health Sciences, Gettysburg, PA, USA