Specificity of exercise in exercise-induced asthma.

Ventilatory function after three types of exercise-running, cycling, and swimming-was studied in 10 control subjects and 40 asthmatic patients. All performed eight minutes of submaximal aerobic exercise during each of the programmes, which were conducted in a randomly selected order. Biotelemetric monitoring of heart rates was used to equate the intensity of the exertion undertaken during the three systems of exercise. No control subject showed any significant variation in ventilatory capacity after exercise, and the responses after the three forms of exercise did not differ.In asthmatics exercise-induced asthma was observed after 72.5% of running tests, 65% of cycling tests, and 35% of swimming tests. In addition, those patients who developed exercise-induced asthma after swimming were noted to have significantly smaller falls in FEV(1) levels than were recorded after running and cycling. These results were statistically significant (P <0.01).The unexplained aetiology of increased airways resistance after exercise in asthmatics is discussed. This study indicates that swimming should be recommended in preference to running or cycling as an exercise programme for adults and children with asthma.