Effects of inspiratory muscle warm-up on perceptual, physiological, and performance outcomes during high-intensity exercise in normoxia and hypoxia

Some evidence shows that an inspiratory muscle warm-up (IMW) could enhance exercise performance; however, the mechanistic basis is unclear. PURPOSE: To examine how IMW affects the sensory and affective components of dyspnea, exercise performance, and locomotor muscle oxygenation. METHODS: Thirteen recreationally active individuals (23 ± 5 yr, 5 women) performed a cycling time to exhaustion test (~80-85% VȮ 2 max) preceded by either IMW (2x30 breaths, 40% maximal inspiratory pressure) or SHAM (2x30 breaths, 15% maximal inspiratory pressure) in normoxic (F I O 2 = 0.21) and hypoxic (F I O 2 = 0.16) conditions (i.e., 4 trials total). NIRS, dyspnea (i.e., breathing intensity and breathing unpleasantness), and cardiorespiratory parameters were measured throughout. Cardiorespiratory variables were analyzed using the individual isotime method. RESULTS: There were no differences in mean dyspnea responses between IMW and SHAM ( p > 0.05). Mean Δ tissue saturation index (TSI) did not reach statistical significance between IMW and SHAM in normoxia ( p = 0.110) or hypoxia ( p = 0.07). Mean performance was not different in normoxia ( p = 0.636) or hypoxia ( p = 0.512). In normoxia, V̇ E ( p = 0.059) and f B ( p = 0.056) approached significance with IMW values greater compared to SHAM in the third isotime. CONCLUSION: Group improvements in dyspnea, performance, and ΔTSI were not seen following IMW. However, the degree of select individual responses suggest this intervention has interindividual applicability that should not be overlooked. No external funding was received for this work. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.