Sodium bicarbonate supplementation improves severe-intensity intermittent exercise under moderate acute hypoxic conditions

Sanjoy K Deb,S Andy Sparks,Lewis A Gough,Lars R Mcnaughton

doi:10.1007/s00421-018-3801-7

Sanjoy K Deb, S Andy Sparks + Show 2 more

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https://doi.org/10.1007/s00421-018-3801-7

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Abstract

Acute moderate hypoxic exposure can substantially impair exercise performance, which occurs with a concurrent exacerbated rise in hydrogen cation (H+) production. The purpose of this study was therefore, to alleviate this acidic stress through sodium bicarbonate (NaHCO3) supplementation and determine the corresponding effects on severe-intensity intermittent exercise performance. Eleven recreationally active individuals participated in this randomised, double-blind, crossover study performed under acute normobaric hypoxic conditions (FiO2% = 14.5%). Pre-experimental trials involved the determination of time to attain peak bicarbonate anion concentrations ([HCO3−]) following NaHCO3 ingestion. The intermittent exercise tests involved repeated 60-s work in their severe-intensity domain and 30-s recovery at 20 W to exhaustion. Participants ingested either 0.3 g kg bm−1 of NaHCO3 or a matched placebo of 0.21 g kg bm−1 of sodium chloride prior to exercise. Exercise tolerance (+ 110.9 ± 100.6 s; 95% CI 43.3–178 s; g = 1.0) and work performed in the severe-intensity domain (+ 5.8 ± 6.6 kJ; 95% CI 1.3–9.9 kJ; g = 0.8) were enhanced with NaHCO3 supplementation. Furthermore, a larger post-exercise blood lactate concentration was reported in the experimental group (+ 4 ± 2.4 mmol l−1; 95% CI 2.2–5.9; g = 1.8), while blood [HCO3−] and pH remained elevated in the NaHCO3 condition throughout experimentation. In conclusion, this study reported a positive effect of NaHCO3 under acute moderate hypoxic conditions during intermittent exercise and therefore, may offer an ergogenic strategy to mitigate hypoxic induced declines in exercise performance.

Highlights

Acute ambient hypoxic environments are often used as an ergogenic strategy to enhance exercise-induced training adaptations (Lundby et al 2012)
An overall main effect for blood [HCO3−] was apparent (Fig. 3a), with a significantly greater concentration observed with NaHCO3 compared to placebo prior to exercise (6.9 ± 1.9 mmol l−1; 95% confidence intervals (CI) 5.6–8.1 mmol l−1)
Blood [HCO3−] remained elevated in the NaHCO3 treatment condition post-exercise compared to placebo (3.0 ± 2.0 mmol l−1; 95% CI 1.6–4.3 mmol l−1), despite the larger reduction in [HCO3−] during exercise in the NaHCO3 condition (− 14.9 ± 2.9 mmol l−1; 95% CI − 16.9 to − 13.0 mmol l−1) compared to placebo during NaHCO3 CI) difference to and placebo experimental trials. *Significant corresponding placebo time point. #Significant

Summary

Introduction

Acute ambient hypoxic environments are often used as an ergogenic strategy to enhance exercise-induced training adaptations (Lundby et al 2012). Methods that involve interspersed acute hypoxic exercise bouts within a training programme, are suggested to augment molecular training adaptations leading to enhanced anaerobic glycolytic activity (Faiss et al 2013). This benefit is not without cost as the lower availability of oxygen (O2) may elicit an ergolytic effect on exercise intensity and volume during intermittent and continuous exercise (Aldous et al 2016; Clark et al 2007). The resultant decline in exercise performance presents a challenge to the management of training load during acute hypoxic training regimes to ensure the acute cost to exercise performance does not hamper the potential medium to long-term benefits of these strategies

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