Activation of the insular cortex is affected by the intensity of
exercise .
Williamson, J. W., R. McColl_, D. Mathews_, M. Ginsburg_ and J. H.
Mitchell.
University of Texas Southwestern Medical Center, Departments of
Physical Therapy*, Radiology_ and the Moss Heart Center$
APStracts 6:0251A, 1999.
The purpose of this investigation was to determine if there were
differences in the magnitude of insular cortex activation across
varying intensities of static and dynamic exercise. Eighteen healthy
volunteers were studied, eight during two intensities of leg cycling,
and 10 at different time periods during sustained static handgrip at
25% MVC or post-exercise cuff occlusion (PECO). Heart rate (HR),
blood pressure (BP), perceived exertion (RPE) and regional cerebral
blood flow (rCBF) distribution data were collected. There were
significantly greater increases in insular rCBF during lower (6.3+/
-1.7%; p < 0.05) and higher (13.3+/-3.8%; p < 0.05) intensity
cycling and across time during static handgrip (change from rest for
right insula at 2-3 min., 3.8+/-1.1%; p < 0.05 and 4-5 min., 8.6+/
-2.8%; p < 0.05). Insular rCBF was decreased during PECO (-5.5+/
-1.2%; p < 0.05) with blood pressure sustained at exercise levels.
Right insular rCBF data, but not left, were significantly related
with individual BP changes (r2=0.80; p < 0.001) and with RPE (r2
=0.79; p < 0.01) during exercise. These results suggest that the
magnitude of insular activation varies with the intensity of
exercise, which may be further related to the level of perceived
effort or central command.
Received 8 October 1998; accepted in final form 26 May 1999.
APS Manuscript Number A909-8.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 14 June 1999