Effect Of High Velocity/Hyperoxic Breathing Therapy On Blood Lactate Kinetics After A Wingate Test

PURPOSE: Maximal effort exercise elevates blood lactate concentration ([La-]b) causing acidosis and fatigue. Post-exercise, [La-]b peaks, then returns towards baseline over an hour. High velocity breathing therapy (HVT) delivers O2, purportedly improving CO2 elimination and ventilatory efficiency. HVT might hasten [La-]b decline, speeding recovery. This study investigated HVT's impact on [La-]b kinetics after intense exercise (Wingate test). METHODS: 15 participants (8 M; 7F; 26 ± 2y) completed a 30s Wingate test, followed by 60 min of recovery under 4 randomized HVT conditions: 21% O2 at 5 L/min, 21% O2 at 35 L/min, 100% O2 at 5 L/min, and 100% O2 at 35 L/min. Cycle ergometer resistance was 0.085 kp/kg body mass. Assessments included Wingate performance metrics, Perceived Recovery Status, Rating-of-Fatigue, and [La-]b. Blood samples were collected pre-exercise and during recovery for [La-]b analysis (Lactate Plus). Recovery [La-]b values were fit to a biexponential equation (Freund et al. 1981) to identify time constants for [La-]b increase (tau1) and decrease (tau2) as well as peak [La-]b and time to peak [La-]b. RESULTS: Recovery status was the same prior to each test (p = 0.2759), as were peak power (p = 0.3896), final power (p = 0.2801), and fatigue index (p = 0.2046). Rating of fatigue improved during recovery with no difference among conditions (p = 0.6773). Peak [La-]b declined numerically but not significantly (p = 0.2211) across conditions from 21% O2 at 5 L/min (11.7 ± 2.2 mM) to 21% O2 at 35 L/min (11.5 ± 2.3 mM) to 100% O2 at 5 L/min (11.3 ± 1.8 mM), and to 100% O2 at 35 L/min (11.0 ± 2.2 mM). There was no difference among conditions for time to peak [La-]b (p = 0.1125; grand mean = 6.5 ± 2.0 min), tau1 (p = 0.7407; grand mean = 4.9 ± 2.4 min), or tau2 (p = 0.5701; grand mean = 23.4 ± 6.9 min). However, there was a tendency for a significantly smaller [La-]b area under the curve over the entire recovery period for 100% O2 at 35 L/min (p = 0.0530). CONCLUSIONS: There was a potential small effect of high velocity air flow in combination with hyperoxia on venous [La-]b kinetics during recovery from maximal effort exercise. FUNDING: Contract from Vapotherm, Inc. Authors Bergeski and Whittle are Vapotherm, Inc. employees. Study design and implementation were independently approved and performed by Auburn University researchers. Supported by: Vapotherm, Inc. research contract