Objective: To evaluate the acute effect of moderate-intensity physical exercise on spirometric variables in asthmatic subjects.
Methodology: A before-and-after type of quasi-experimental design. Ten subjects were included (mean age= 23 ± 4 years), which were divided into two groups: five asthmatic subjects and five healthy subjects. Both groups performed 10 min of warm-up, 20 min of treadmill exercise at an intensity of 60 % of the Heart Rate Reserve, and a final cool-down of 5 minutes. Lung function was assessed before and 15 minutes after exercise.
Results: There were statistically significant differences between groups (with asthma = 6 % vs. without asthma = -1 %, p = 0.03) in the pre-post-exercise changes of the ratio of the forced expiratory volume in one second and the forced vital capacity (FEV1/FVC). The multivariate analysis showed that post-exercise FVC in subjects with asthma was significantly lower than in subjects without asthma, after adjusting for the baseline assessment and total body mass.
Conclusion: Moderate-intensity exercise on a treadmill did not shows clinically significant differences in the changes pre-post exercise of the studied spirometric variables, since the changes on FEV1 or FVC did not exceed 10 % having as reference the baseline evaluation.
Keywords: Asthma, Exercise-Induced; Airway Obstruction; Body Composition; Motor Activity; Spirometry.