Influência aguda da irradiação intravascular de sangue a laser modificada (ILIB) sobre a potência anaeróbia e estimadores cardiovasculares em sujeitos ativos

Abstract

Introduction: Intravascular Laser Irradiation of Blood (ILIB) is a low-power laser technique with systemic effects. It has demonstrated various effects through different mechanisms of action, such as activation of the antioxidant system, inhibition of the systemic inflammatory process, increased blood fluidity, and improvements in hemorheological properties related to erythrocytes. Objective: To investigate the acute influence of ILIB on muscular power and cardiovascular aspects, including heart rate variability (HRV), in physically active individuals subjected to a submaximal effort test. Methodology: This study is a randomized controlled crossover clinical trial. Fourteen male participants, university students with an average age of 23.1 ± 4.1 years, and regular physical activity practitioners, were evaluated. Volunteers participated in two intervention groups (ILIB and placebo) at separate times, for the ILIB intervention, the following parameters were adopted, 30 min of irradiation, wavelength of 660nm, power of 100mW and beam area of 3mm. In the first phase, subjects were assessed for sample characterization and underwent an evaluation session, including assessment of cardiovascular indicators, resting blood lactate levels, and response to the effort test. Subsequently, participants received a session of the experimental protocol, which was randomized. After completing the experimental protocol sessions, a new session was conducted to reassess cardiovascular indicators and resting blood lactate levels and response to the effort test. After seven days, the entire collection was repeated, with participants undergoing the remaining experimental protocol. Results: During the Wingate test, the analyzed variables included maximum power, relative maximum power, mean power, relative mean power, and fatigue index. Only the fatigue index showed a statistically significant difference (p<0,05) in the post-ILIB stage (43,2±9,9%) compared to the post-PB (52,5±14,9%). Resting heart rate (HR) showed a reduction after ILIB use (63,0±8,3 bpm) compared to the other stages. Additionally, for blood lactate, the recovery period after ILIB use (5.9 ± 2.7 mmol/L) showed a significant difference (p<0,05) compared to the other stages. In HRV, the RMSSD and pNN50 showed a significant difference (p<0,05) in post-ILIB rest (1,83±0,12 ms; 1,64 ± 0,11%), compared to the pre-ILIB (1,53±0,19 ms; 1,21±0,32%). The HF index also showed a significant difference (p<0,05) between the post-ILIB stage (1,70±0,03 ms²) and the post-PB stage (1,49 ±0,28 ms). Conclusion: The use of ILIB delayed the onset of fatigue in a submaximal exercise test and reduced blood lactate concentration during short-term recovery. Furthermore, ILIB increased heart rate variability, indicating enhanced parasympathetic activity.