Near-Infrared Spectroscopy Used to Assess Physiological Muscle Adaptations in Exercise Clinical Trials: A Systematic Review
Usingmuscle oxygenation to evaluate the therapeutic effects of physical exercise in pathologies through near-infrared spectroscopy (NIRS) is of great interest. The aimof this reviewwas to highlight the use ofmuscle oxygenation in exercise interventions in clinical trials and to present the technological characteristics related to the equipment used in these studies. PubMed,WOS, and Scopus databaseswere reviewed up to December 2021. Scientific articles that evaluatedmuscle oxygenation after exercise interventions in the sick adult population were selected. The PEDro scale was used to analyze the risk of bias (internal validity). The resultswere presented grouped in tables considering the risk of bias scores, characteristics of the devices, and the effects of exercise onmuscle oxygenation. All the stages were carried out using preferred reporting items for systematic reviews and meta-analyses (PRISMA). The search strategy yielded 820 clinical studies, of which 18met the eligibility criteria. This reviewdetailed the characteristics of 11NIRS devices used in clinical trials that used physical exercise as an intervention. The use of this technologymade it possible to observe changes inmuscle oxygenation/deoxygenation parameters such as tissue saturation, oxyhemoglobin, total hemoglobin, and deoxyhemoglobin in clinical trials of patientswith chronic disease. Itwas concluded that NIRS is a non-invasivemethod that can be used in clinical studies to detect the effects of physical exercise training onmuscle oxygenation, hemodynamics, andmetabolism. Itwill be necessary to unify criteria such as the measurement site, frequency, wavelength, and variables for analysis. This will make it possible to compare differentmodels of exercise/training in terms of time, intensity, frequency, and type to obtainmore precise conclusions about their benefits for patients.