Ventilatory response to exercise in diabetics with autonomic
neuropathy effects of chronic lung denervation .
Tantucci, C., P. Bottini, M. L. Dottorini, E. Puxeddu, G. Casucci, L.
Scionti, C. A. Sorbini.
Dr. Claudio Tantucci, Clinica di Semeiotica Medica, University of
Ancona, Ospedale Regionale Torrette, 60020 - Ancona, Italy, Ph: (071)
883913, Fax: (071) 88391, Clinica di Semeiotica e Metodologia Medica,
University of
APStracts 3:0054A, 1996.
We have used diabetic autonomic neuropathy as a model of chronic
pulmonary denervation to study the ventilatory response to
incremental exercise in 20 diabetics, 10 with (Dan+) and 10 without
(Dan-) autonomic dysfunction, and in 10 normal controls (C). Although
both Dan+ and Dan- achieved lower VO2 and VCO2 than C at peak of
exercise, they attained similar values of either minute ventilation
(VE) or adjusted ventilation (VE/MVV). The increment of respiratory
rate with increasing adjusted ventilation was much higher in Dan+
than in Dan- and C (p<0.05). The slope of the linear VE/VCO2
relationship was 0.032+0.002 ml/min in Dan+, 0.027+0.001 ml/min in
Dan- (p<0.05) and 0.025+0.001 ml/min in C (p<0.001). Both
neuromuscular (P0.1) and ventilatory (VA) outputs in relation to
increasing VCO2 were progressively higher in Dan+ than in Dan- and C.
At peak of exercise end-tidal PCO2 was much lower in Dan+ (35.9+1.6
mmHg) than in Dan- (42.1+1.7 mmHg, p<0.02) and C (42.1+0.9 mmHg,
p<0.005). We conclude that pulmonary autonomic denervation
affects ventilatory response to stressful exercise by excessively
increasing respiratory rate and alveolar ventilation. Reduced neural
inhibitory modulation from sympathetic pulmonary afferents and/or
increased chemosensitivity may be responsible for the higher
inspiratory output.
Received 30 March 1995; accepted in final form 10 January 1996.
APS Manuscript Number A349-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 January 96