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Keywords:

  • cutaneous vascular conductance;
  • exercise;
  • mean surface temperature;
  • pulmonary gas exchange;
  • respiratory physiology

Summary

Pulmonary diffusion capacity for carbon monoxide (DLCO) is reduced by approximately 10% 1–6 h after maximal exercise. The mechanisms may be interstitial alveolar oedema and reduced pulmonary capillary blood volume. It was hypothesized that thermal stress following exercise contributes to the reduction in DLCO, and that skin cooling would attenuate the postexercise reduction in DLCO. Cutaneous vascular conductance (CVC), mean surface temperature (MST), rectal temperature and DLCO were measured before and 90 min after maximal incremental cycle exercise. Thereafter, the subjects were exposed to cold air without eliciting shivering one day and another day served as control. The measurements were repeated 120 min after exercise. Twelve healthy subjects (six male) aged 20–27 years were studied. DLCO was reduced by 7·1% (SD = 6·3%, P = 0·003) and 7·6% (SD = 5·3%, P<0·001) 90 and 120 min after exercise in the control experiment. It was reduced by 5·6% (SD = 5·5%, P = 0·014) 90 min after exercise and remained reduced by 6·1% (SD = 6·1%, P = 0·012) after cooling despite a significant reduction in CVC and in MST from 31·9 (SD = 0·6)°C to 27·4 (SD = 1·9)°C. We conclude that the postexercise reduction in DLCO is present when thermal status is restored after exercise, and that it is not influenced by further skin surface cooling.