Thermoregulatory and respiratory responses in asthmatic and nonasthmatic subjects breathing cold and warm air during exercise in the cold

1.The effects of whole-body exposure to ambient temperature of −15 °C on thermoregulatory and respiratory responses in asthmatic and nonasthmatic subjects were investigated. The subjects were exposed to inhalation of cold dry and warm humid air during 30 min submaximal exercise.2.Exercise-induced bronchoconstriction in the asthmatic group was significantly reduced, but not eliminated by inspiration of warm, humid air. The reduction was significantly larger in the asthmatic than in the nonasthmatic group.3.Higher oxygen uptake was measured when cold, rather than warm humid air was breathed during exercise in both groups.4.Mean skin temperature and maximal finger temperature were higher when breathing warm compared with cold air.