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Luana Farias de Oliveira, Bryan Saunders and Guilherme Giannini Artioli

Sodium bicarbonate (SB) is an ergogenic supplement shown to improve high-intensity exercise via increased blood bicarbonate buffering. Substantial amounts of the ingested bicarbonate are neutralized in the stomach. Bariatric surgery results in a small gastric pouch which dramatically reduces exposure time of any ingested food in the stomach. The aim of this study was to examine the pharmacokinetics of orally ingested SB in a postgastric bypass individual to determine the magnitude of changes in blood bicarbonate and associated side effects. We hypothesized that SB supplementation in a gastric bypass model would result in greater blood bicarbonate increases and fewer side effects than in healthy individuals due to minimal bicarbonate losses in the stomach. One postbariatric male ingested 0.3 g/kg·body mass of SB on three occasions (SB1, SB2, and SB3) and 0.3 g/kg·body mass of placebo on a further occasion. Blood bicarbonate was determined before and every 10 min following supplement ingestion for 3 hr and then every 20 min for a further 1 hr. Side effects were reported using an adapted questionnaire at identical time points. Maximal increases in blood bicarbonate with SB were +20.0, +15.2, and +12.6 mM, resulting in maximal bicarbonate concentrations of 42.8, 39.3, and 36.2 mM. Area under the curve was SB1: 8,328 mM/min; SB2: 7,747 mM/min; SB3: 7,627 mM/min, and 6,436 mM/min for placebo. Side effects with SB were scarce. Maximal bicarbonate increases were well above those shown previously, with minimal side effects, indicative of minimal neutralization of bicarbonate in the stomach. The large increases in circulating bicarbonate and minimal side effects experienced by our postgastric surgery bypass patient are indicative that minimizing neutralization of bicarbonate in the stomach, as would occur with enteric coated capsules, may optimize SB supplementation and thus warrants investigation.

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David Morawetz, Tobias Dünnwald, Martin Faulhaber, Hannes Gatterer, Lukas Höllrigl, Christian Raschner and Wolfgang Schobersberger

Background: The altering effects of hypoxia on aerobic/anaerobic performance are well documented and form the basis of this study. Application of hyperoxic gases (inspiratory fraction of oxygen [FiO2] > 0.2095) prior to competition or training (hyperoxic preconditioning) can compensate for the negative influence of acute hypoxia. Purpose: To investigate whether oxygen supplementation immediately prior to exercise (FiO2 = 1.0) improves all-out exercise performance in normobaric hypoxia (3500 m) in highly skilled skiers. Methods: In this single-blind, randomized, crossover study, 17 subjects performed a 60-second constant-load, all-out test in a normobaric hypoxic chamber. After a short period of adaptation to hypoxia (60 min), they received either pure oxygen or chamber air for 5 minutes prior to the all-out test (hyperoxic preconditioning vs nonhyperoxic preconditioning). Capillary blood was collected 3 times, and muscle oxygenation was assessed with near-infrared spectroscopy. Results: Absolute and relative peak power (P = .073 vs P = .103) as well as mean power (P = .330 vs P = .569) did not significantly differ after the hyperoxic preconditioning phase. PaO2 increased from 51.3 (3) to 451.9 (89.0) mm Hg, and SaO2 increased from 88.2% (1.7%) to 100% (0.2%) and dropped to 83.8% (4.2%) after the all-out test. Deoxygenation (P = .700) and reoxygenation rates (P = .185) did not significantly differ for both preconditioned settings. Conclusions: Therefore, the authors conclude that hyperoxic preconditioning did not enhance 60-second all-out exercise performance in acute hypoxia (3500 m).