Effects of High-Intensity Inspiratory Muscle Warm-Up on High-Intensity Exercise Performance and Muscle Oxygenation.

Abstract

An inspiratory muscle warm-up (IMW) improves inspiratory muscle function, but the effects of high-intensity exercise are inconsistent. We aimed to determine the effects of high-intensity IMW on high-intensity exercise performance and muscle oxygenation. Ten healthy men (maximal oxygen uptake [V˙O2max] 52.2 [5.0]mL·kg-1·min-1) performed constant-load exercise to exhaustion on a cycle ergometer at V˙O2max under 2 IMW conditions: a placebo condition (PLA) and a high-intensity IMW condition (HIGH). The inspiratory loads were set at 15% and 80% of maximal inspiratory pressure, respectively. Maximal inspiratory pressure was measured before and after IMW. Oxyhemoglobin was measured in the vastus lateralis by near-infrared spectroscopy during exercise. Rating of perceived exertion (RPE)for a leg was measured after 1 and 2minutes of exercise. Exercise tolerance was significantly higher under HIGH than PLA (228 [49]s vs 218 [49]s, P = .003). Maximal inspiratory pressure was significantly increased by IMW under HIGH (from 125 [20] to 136 [25] cm H2O, P = .031). Oxyhemoglobin was significantly higher under HIGH than PLA at 80% of the total duration of exercise (P = .048). RPE for the leg was significantly lower under HIGH than PLA after 2minutes of exercise (P = .019). Given that oxyhemoglobin is an index of local oxygen supply, the results of this study suggest that high-intensity IMW increases the oxygen supply to active limbs. It may also reflect a reduction in RPE in the leg. In addition, high-intensity IMW may improve exercise performance.