Exercise-induced bronchospasm at low temperature in elite runners.

BACKGROUND Healthy elite runners often report bronchial symptoms when training in subzero temperatures. The occurrence and causes of exercise-induced bronchospasm after heavy exercise in cold air were investigated in elite runners. METHODS Thirty two non-asthmatic runners, mostly from Finnish national teams, volunteered to take part in the study. They answered a questionnaire and were subjected at subzero temperature to a heavy exercise challenge test combined with lung function testing. RESULTS Sixteen of the runners were atopic on skin prick tests. The mean (SD) maximal change in forced expiratory volume in one second (FEV1) after the exercise challenge was -4.8 (7.1)% in the atopic runners, and +2.1 (3.4)% in the non-atopic runners. When the mean maximal change in FEV1 minus 2SD (-4.7%) of the exercise response of the non-atopic runners was taken as the lower limit of a "normal" result, eight of the atopic runners responded abnormally. CONCLUSIONS Heavy exercise at temperatures below zero causes bronchospasm in a high proportion of elite runners with atopy. Although the changes in lung function are mostly small, they may affect the maximal performance of atopic runners. Non-atopic runners are not affected.