Inspiratory muscle training improves autonomic modulation and exercise tolerance in chronic obstructive pulmonary disease subjects: A randomized-controlled trial.

OBJECTIVES

We aimed to evaluate the effect a regular inspiratory muscle training program on autonomic modulation measured by heart rate variability, exercise capacity and respiratory function in chronic obstructive pulmonary disease subjects (COPD).

DESIGN

Single-center controlled study, with balanced randomization (1:1 for two arms).

SETTING

A COPD reference hospital localized in Sao Luís, Brazil.

PARTICIPANTS

22 COPD subjects joined the study.

INTERVENTIONS

Three times a week for four weeks inspiratory muscle training (IMT) at 30% of PI.

MAIN OUTCOME MEASURES

Pulmonary capacities and inspiratory pressure, total six-minute walk test and, cardiac autonomic modulation.

RESULTS

The intervention group showed improvements in the cardiac autonomic modulation, with increased vagal modulation (total variability and HF [ms; adjusted p < 0.05]); increased expiratory and inspiratory capacities and, increased distance in the 6-min walk test.

CONCLUSION

12 weeks of IMT at 30% of the maximal inspiratory pressure increased cardiac autonomic modulation, expiratory and inspiratory and exercise capacity in COPD subjects.