VO2 kinetics in asthmatic adolescents: A pilot study

In normal subjects, ventilatory rate and oxygen ventilation (VO 2 ) increases during exercise from a resting state until maximal levels are attained, whereas it seems that in asthmatic patients this increase is higher. The aim of the study was to evaluate the kinetics of VO 2 during a constant-load exercise in a group of 11-16 y.o. asthmatic patients. 17 adolescents with mild stable asthma were studied. On the first day a progressive workload was applied to calculate the presumable aerobic threshold, which was assumed to be 80% of the maximum load tolerated. On the next day the subjects were asked to pedal at this constant load and the VO 2 kinetics were studied with a K4B2 and a Cosmed® cycloergometer. In 9 patients (53%) there was an increasing trend of VO 2 consumption, whereas in 5 (29%) this trend was not highlighted. In 3 patients (18%) data was unobtainable because of incompletion of test or non-cooperation. In conclusion, it was not possible to outline a common pattern of VO 2 consumption, but in more than a half of our patients the behaviour of VO 2 consumption during constant load was similar to that of the normal population.