Inspiratory Muscle Warm-Up and Perceptual, Physiological, and Performance Outcomes During Exercise in Normoxia and Hypoxia.

Introduction: Some evidence shows that an inspiratory muscle warm-up (IMW) could enhance exercise performance; however, outcomes are mixed, and the mechanistic basis is unclear. Therefore, our purpose was 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] y, 5 women) performed a cycling time-to-exhaustion test (∼80%-85% maximal oxygen uptake) preceded by either IMW (2 × 30 breaths, 40% maximal inspiratory pressure) or SHAM (2 × 30 breaths, 15% maximal inspiratory pressure) in normoxic (FIO2 = 0.21) and hypoxic (FIO2 = 0.16) conditions (ie, 4 trials total). Near-infrared spectroscopy, dyspnea (ie, 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 > .05). Mean Δ tissue saturation index did not reach statistical significance between IMW and SHAM in normoxia (P = .110) or hypoxia (P = .07). Mean performance was not different in normoxia (P = .636) or hypoxia (P = .512). In normoxia, minute ventilation (P = .059) and breathing frequency (P = .056) approached significance with IMW values greater compared with SHAM in the third isotime.

Conclusion: Group improvements in dyspnea, performance, and Δ tissue saturation index were not seen following IMW. However, the degree of selected individual responses suggests that this intervention has interindividual applicability that should not be overlooked.