Efeitos agudos da fototerapia por LED na fadiga muscular e nas respostas cardiorrespiratórias ao exercício físico em pacientes com doença pulmonar obstrutiva crônica

Abstract

Peripheral muscle dysfunction is a common finding in patients with chronic obstructive pulmonary disease (COPD) once two thirds of patients interrupt the exercise by muscle fatigue as limiting or symptom associated with dyspnea. The objective of this study was to evaluate the acute effects of light emitting diode (LED) on muscle function, exercise capacity and cardiorespiratory responses in dynamic and isometric exercise in patients with COPD. Twenty patients were selected with moderate to severe obstruction (FEV1 70% of predict). Patients performed test of maximum voluntary isometric contraction (MVIC), sustained isometric contraction 60% (SIC) with of the concomitant electromyographic record MVIC, application of LED or placebo (PL) of randomly. The dynamic exercise protocol followed the same procedures; however, the endurance test was conducted in cycle ergometer. Twenty patients (FEV1 46 ± 13% prev) received LED and PL with 1 week of interval between visits. Statistical difference was found between pre-LED and post-LED (31 ± 8 s vs 54 ± 13 s) and when compared pre-and post-placebo (27 ± 9 s vs 31 ± 10 s; respectively), the greatest decline in median frequency (MF) was observed during the endurance test post-PL compared to LED (P= 0.008), straight tilt MF along the endurance test was smaller post-LED in relation post-placebo (-0.65 ± 0.34 vs. -1.47 ± 0.72; P= 0.015). We observed increase in endurance time during post-LED in dynamic protocol when compared after placebo. We conclude that the application of LED was able to increase the time of isometric and dynamic endurance in patients with COPD.