EXERCISE-INDUCED AIRWAY NARROWING IN ARMY RECRUITS WITH A HISTORY OF CHILDHOOD ASTHMA

The aim of this study was to determine whether the addition of cold, d ry, inspired air to maximum heart rate (MHR) exercise increased the nu mber of subjects demonstrating abnormal airway narrowing, when applied to symptom-free army recruits with a history of asthma in childhood. One hundred recruits with a history of asthma in childhood underwent t wo exercise challenges to maximum heart rate, breathing either room ai r or cold dry air in randomized order, The percentage fall index(%FI) was calculated for each challenge, a positive result being greater tha n or equal to 15%. A total of 29 subjects had a positive % fall index, 12 subjects were positive to both challenges, 7 to the room air alone and 10 to the cold air challenge alone, In these subjects (n=29), the mean (so) % fall index to the cold air challenge was 22.7 (11.0)% com pared with 16.3 (9.5)% for the room air challenge. We conclude that wh en employed as a screening test for abnormal airway narrowing, the add ition of cold, dry, inspired air during exercise does not increase the number of subjects with a positive response, but the magnitude of the response is increased.