Cold air inhalation does not affect the severity of EIB after exercise or eucapnic voluntary hyperventilation.

INTRODUCTION

Exercise-induced bronchoconstriction (EIB) is thought to result from osmotic and thermal events of air conditioning during exercise at high ventilation rates. The purpose of this study was to evaluate lung function after exercise and eucapnic voluntary hyperventilation (EVH) while breathing both room-temperature and cold-temperature dry bottled air.

METHODS

Twenty-two subjects were identified as EIB probable by a fall of >or=7% in forced expiratory volume in the first second of exhalation (FEV1) using a 6-min room-temperature EVH challenge (RTEVH; 22.0 degrees C). Subjects then randomly performed three 6-min challenges: cold-temperature EVH (CTEVH; -1 degrees C), room-temperature exercise (RTEX; 22.0 degrees C), and cold-temperature exercise (CTEX; -1 degrees C), with a period of at least 48 h observed between challenges. Spirometry was performed at baseline and at 5, 10, 15, and 20 min postchallenge.

RESULTS

Reasonable agreement was found between challenge modes and room-temperature and cold-temperature challenges. Postchallenge percent falls in FEV1 were -15.21, -13.80, -13.12, and -10.69 for RTEVH, CTEVH, RTEX, and CTEX, respectively. RTEVH resulted in a significantly greater percent fall in FEV1 than CTEX (P=0.048); no other differences in FEV1 were observed.

CONCLUSION

Similar postchallenge percent falls in FEV1 for room- and cold-temperature EVH and exercise suggest that dryness is essential to test conditions, as cold temperature did not have an additive effect to the EIB response.