The primary objective of this study was to investigate the effects of a 4-week respiratory muscle endurance training (eRMT) program on the physiological and psychological aspects of central fatigue using, respectively, near-infrared spectroscopy (NIRS) and quantification of effort perceptions during maximal exercise. A secondary objective was to assess any impact of eRMT on respiratory health and exercise performance. This study compared pre- and post-eRMT data from the same group of healthy adults. The results indicated that eRMT did not have any effect on respiratory function, exercise time to exhaustion, or physiological responses to exercise but significantly decreased ratings of perceived exertion (RPE) during exercise. An increase in the concentrations of oxygenated hemoglobin [O2Hb], deoxygenated hemoglobin [HHb], and total hemoglobin [tHb] during exercise was observed post-eRMT compared to pre-eRMT, and this increase differed by hemisphere. Based on these preliminary findings, we suggest an eRMTinduced left-to-right hemodynamic shift during exercise, consistent with the change from a novel to a learned task.
