Lasers in Medical Science | 2019
Acute effects of photobiomodulation therapy applied to respiratory muscles of chronic obstructive pulmonary disease patients: a double-blind, randomized, placebo-controlled crossover trial
Abstract
To investigate the effects of photobiomodulation applied to respiratory muscles on lung function, thoracoabdominal mobility, respiratory muscle strength, and functional capacity in COPD patients. This is a randomized double-blind crossover clinical trial. Twelve male COPD patients participated in the study. Participants were randomly allocated to receive two photobiomodulation sessions, 1\xa0week apart: (1) an effective photobiomodulation session applied at the main respiratory muscles by means of a cluster with 69 light-emitting diodes (LEDs), containing 35 red (630\u2009±\u200910\xa0nm; 10\xa0mW; 0.2\xa0cm 2 ) and 34 near-infrared (830\u2009±\u200920\xa0nm; 10\xa0mW; 0.2\xa0cm 2 ) LEDs and (2) a sham photobiomodulation session, following the same procedures without emitting light. The primary outcomes were pulmonary function (spirometric indexes); thoracoabdominal mobility (cirtometry); respiratory muscle strength (maximal respiratory pressures), assessed at three moments: (1) baseline, (2) 1\xa0h after intervention, and (3) 24\xa0h after intervention; and the functional capacity, assessed by the 6-min walk test (6MWT) at baseline and 24\xa0h after intervention. No significant interactions were found for spirometric variables, maximal respiratory pressures, and cirtometry. However, there was a Time × Condition interaction ( F \u2009=\u200918.63; p \u2009=\u20090.001; η 2 p \u2009=\u20090.62) in the walked distance on the 6MWT, with a significant increase after photobiomodulation intervention ( p \u2009<\u20090.01) compared with the baseline. Photobiomodulation applied to respiratory muscles was effective in improving acute functional capacity in COPD patients. To the best of our knowledge, this is the first study assessing the effects of photobiomodulation applied to respiratory muscles in patients with COPD.