A single section of stretch of the respiratory muscles does not influence the pulmonary volume of asthmatics during exercise

Abstract

Goal: Evaluate the acute effects of respiratory muscles (RM) stretching in lung volume, respiratory frequency (RF), minute volume (MV), shortening speed index of RM and exercise tolerance in asthmatic.

Methods: crossover study, randomized, double blind, allocation in stretching group (SG) and placebo group (PG). Lung volumes, RF, MV and shortening speed index of RM were compared by two-way ANOVA, Bonferroni’s post hoc. For the time of exercise tolerance and perceived exertion, the paired t-test.

Results: asthmatic 11 (35.5 ± 7.8 years, BMI = 24.4 ± 2.4 Kg/m², FVC and FEV₁ of 95.8 ± 10.3 and 11.5 ± 85.3% of the predicted). There were no differences in lung volumes (SG vs. PG) in exercise, intra-group differences occurring during its steps (p < 0.01). The RF and MV were similar in the groups (p = 0.52 and 0.68). The index of the RM speed showed no differences between the groups (p = 0.27). The time of exercise tolerance was similar in the groups (p = 0.31). The variance of the Borg scale (fatigue) was lower in SG (p = 0.02).

Conclusion: The stretching of RM does not modify pulmonary volumes, RF, MV, and RM shortening speed index of asthmatic in the exercise. There was no influence on exercise tolerance, but we observed less fatigue in SG.