Effect of training and recovery on airway inflammation in an animal model of 'ski asthma'

摘要

Repeated strenuous exercise while breathing cold air is believed to induce chronic airway inflammation and hyperreactivity, a condition referred to in humans as 'ski asthma'. However, the time course of development and resolution of ski asthma is unknown. We have previously shown that multi-day aerobic exercise induces airway inflammation and hyperreactivity in racing sled dogs. In the present study, a similar group of subjects was examined at multiple times during training to test the hypothesis that ski asthma spontaneously resolves during seasonal detraining, but is re-induced during training in the cold weather. At the beginning of training, bronchoalveolar lavage fluid (BALF) from detrained elite sled dogs (n = 16) had higher concentrations oflymphocytes (median 53.63 vs. 8.30 cells mu l~(-1)) and neutrophils (median 23.03 vs. 1.10 cells mu l~(-1)) compared with normal laboratory dogs (n = 5). However, there was no significant effect of training on BALF nucleated cell concentrations from exercised sled dogs (n = 11) compared with sedentary sled dogs (n = 8). In contrast to our hypothesis, our data support the contention that cold weather exercise-induced airway inflammation can persist through seasonal detraining, but that routine training does not cause significant worsening of the condition.