Light-emitting diode therapy (photobiomodulation) effects on oxygen uptake and cardiac output dynamics during moderate exercise
transitions: a randomized, crossover, double-blind, and placebo-controlled study.
Lasers Med Sci. 2018 Jul;33(5):1065-1071
Authors: Beltrame T, Ferraresi C, Parizotto NA, Bagnato VS, Hughson RL
Light-emitting diodes (LEDs) might have a beneficial impact on cytochrome-c oxidase enzyme activity. Thus, it was hypothesized that photobiomodulation by light-emitting diode therapy (LEDT) could influence aerobic
metabolism dynamics. Possible LEDT-mediated aerobic
improvements were investigated mainly by a precise characterization of the pulmonary O2 uptake dynamics during moderate exercise
transitions. Eight healthy young adults were enrolled in this randomized, double-blind, placebo-controlled, crossover study. A multi-diode array of LEDs was used for muscular pre-conditioning 30 min and 6 h before exercise testing. Pulmonary O2 uptake, carbon dioxide output, cardiac output, heart rate, stroke volume, and total arteriovenous oxygen difference dynamics were evaluated by frequency domain analysis. Comparisons revealed no statistical (p > 0.05) differences between LEDT and placebo
, suggesting no significant changes in aerobic system dynamics. These results challenge earlier publications that reported changes in pulmonary O2 uptake during incremental exercise until exhaustion after LEDT. Perhaps, increments in peak pulmonary O2 uptake after LEDT may be a consequence of higher exercise tolerance caused by non-aerobic-related factors as opposed to an improved aerobic response.
PMID: 29516305 [PubMed - indexed for MEDLINE]