Ventilatory response to exercise in diabetic subjects with autonomic neuropathy

J Appl Physiol (1985). 1996 Nov;81(5):1978-86. doi: 10.1152/jappl.1996.81.5.1978.


We have used diabetic autonomic neuropathy as a model of chronic pulmonary denervation to study the ventilatory response to incremental exercise in 20 diabetic subjects, 10 with (Dan+) and 10 without (Dan-) autonomic dysfunction, and in 10 normal control subjects. Although both Dan+ and Dan- subjects achieved lower O2 consumption and CO2 production (VCO2) than control subjects at peak of exercise, they attained similar values of either minute ventilation (VE) or adjusted ventilation (VE/maximal voluntary ventilation). The increment of respiratory rate with increasing adjusted ventilation was much higher in Dan+ than in Dan- and control subjects (P < 0.05). The slope of the linear VE/VCO2 relationship was 0.032 +/- 0.002, 0.027 +/- 0.001 (P < 0.05), and 0.025 +/- 0.001 (P < 0.001) ml/min in Dan+, Dan-, and control subjects, respectively. Both neuromuscular and ventilatory outputs in relation to increasing VCO2 were progressively higher in Dan+ than in Dan- and control subjects. At peak of exercise, end-tidal PCO2 was much lower in Dan+ (35.9 +/- 1.6 Torr) than in Dan- (42.1 +/- 1.7 Torr; P < 0.02) and control (42.1 +/- 0.9 Torr; P < 0.005) subjects. 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.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anaerobic Threshold / physiology
  • Autonomic Nervous System Diseases / physiopathology*
  • Blood Glucose / metabolism
  • Carbon Dioxide / metabolism
  • Diabetic Neuropathies / physiopathology*
  • Electrocardiography
  • Exercise / physiology*
  • Humans
  • Lactic Acid / blood
  • Male
  • Oxygen Consumption / physiology
  • Pulmonary Gas Exchange / physiology
  • Respiratory Function Tests
  • Respiratory Mechanics / physiology*


  • Blood Glucose
  • Carbon Dioxide
  • Lactic Acid