Wearable positive end-expiratory pressure valve improves exercise performance

We tested a PEEP (4.2 cmH₂O) mouthpiece (PMP) on maximal cycling performance in healthy adults. Experiment-1, PMP vs. non-PMP mouthpiece (CON) [n  = 9 (5♂), Age = 30 ± 2 yr]; Experiment-2, PMP vs. no mouthpiece (NMP) [n = 10 (7♂), Age = 27 ± 1 yr]. At timepoint 1 in both experiments (mouthpiece condition randomized) subjects performed graded cycling testing (GXT) (Corival® cycle ergometer) to determine $$ O_{2peak (ml∗kg∗min} ^-1), O₂pulse _(mlO ^-1), GXT endurance time (GXT-T_(s)), and $$ O_{2(ml∗kg∗min} ^-1)-at-ventilatory-threshold ( $$ O₂ @VT). At timepoint 2 72 h later, subjects completed a ventilatory-threshold-endurance-ride [VTER_(s)] timed to exhaustion at $$ O₂ @VT power _(W). One week later at timepoints 3 and 4 (time-of-day controlled), subjects repeated testing protocols under the alternate mouthpiece condition. Selected results (paired T-test, p<0.05): Experiment 1 PMP vs. CON, respectively: $$ O_2peak ​= ​45.2 ​± ​2.4 vs. 42.4 ​± ​2.3 p<0.05; $$ O₂@VT ​= ​33.7 ​± ​2.0 vs. 32.3 ​± ​1.6; GXT-TTE ​= ​521.7 ​± ​73.4 vs. 495.3 ​± ​72.8 (p<0.05); VTER ​= ​846.2 ​± ​166.0 vs. 743.1 ​± ​124.7; O2pulse ​= ​24.5 ​± ​1.4 vs. 23.1 ​± ​1.3 (p<0.05). Experiment 2 PMP vs. NMP, respectively: $$ O_2peak ​= ​43.3 ​± ​1.6 vs. 41.7 ​± ​1.6 (p<0.05); $$ O₂@VT ​= ​31.1 ​± ​1.2 vs. 29.1 ​± ​1.3 (p<0.05); GXT-TTE ​= ​511.7 ​± ​49.6 vs. 486.4 ​± ​49.6 (p<0.05); VTER 872.4 ​± ​134.0 vs. 792.9 ​± ​122.4; O₂pulse ​= ​24.1 ​± ​0.9 vs. 23.4 ​± ​0.9 (p<0.05). Results demonstrate that the PMP conferred a significant performance benefit to cyclists completing high intensity cycling exercise.