Override of the spontaneous respiratory pattern generator during
voluntary control of breathing reduces parasympathetic influence in
cardiovascular regulation.
Patwardhan, A. R., S. Vallurupalli, J. M. Evans, E. N. Bruce, and C.
F. Knapp.
Center for Biomedical Engineering, University of Kentucky,
Lexington, KY 40506-0070
APStracts 2:0180A, 1995.
We investigated the effects of voluntary control of breathing on
autonomic function in cardiovascular regulation. Variability in heart
rate was compared between five minutes of spontaneous and controlled
breathing. During controlled breathing, for five minutes, subjects
voluntarily reproduced their own spontaneous breathing pattern (both
rate and volume on a breath by breath basis). Using this experimental
design, we could unmask the effects of voluntary over-ride of the
spontaneous respiratory pattern generator on autonomic function in
cardiovascular regulation without the confounding effects of altered
respiratory pattern. Results from ten subjects showed that during
voluntary control of breathing, mean values of heart rate and blood
pressure increased, while fractal and spectral powers in heart rate
in the respiratory frequency region decreased. End tidal CO2 was
similar during spontaneous and controlled breathing. These results
indicate that the act of voluntary control of breathing decreases the
influence of the vagal component, which is the principal
parasympathetic influence in cardiovascular regulation.
Received 10 February 1995; accepted in final form 24 April 1995.
APS Manuscript Number A155-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 9 May 1995.