The effectiveness of sodium bicarbonate as an ergogenic aid in normoxia and hypoxia: the importance of ingestion dose and timing

Abstract

The use of sodium bicarbonate (NaHCO3) as an ergogenic aid has been widely researched and also practiced by the athletic community. Despite this, fundamental issues have not been addressed, including a full profile of NaHCO3�s effects on the bicarbonate ion (HCO3-), the dose-dependent effects on performance and gastrointestinal discomfort (GI), and the most optimal timing of ingestion. Recently, an individualised NaHCO3 ingestion strategy has been advocated, which entails supplementing NaHCO3 at a pre-determined time to peak pH or HCO3-. The reproducibility of both the blood and performance responses using this strategy remains unknown however, and therefore Study 1 investigated the reproducibility of the blood acid base balance responses following NaHCO3 ingestion in two separate doses of 0.2 g.kg-1 BM (SBC2) and 0.3 g.kg-1 BM NaHCO3 (SBC3). This study revealed that pH and HCO3- kinetics following both doses were highly reproducible, although HCO3- displayed greater reproducibility. Furthermore, both doses increased pH and HCO3- to a level that would suggest ergogenic benefits could be elicited. As a result, both the reproducibility of the performance responses (Study 2) and the performance effects against a placebo (Study 3) were investigated following both SBC2 and SBC3, administered at a pre-determined individual time to peak HCO3-. Both SBC treatments revealed highly reproducible performance responses, and displayed similar improvements in performance compared to a placebo during a 4 km cycling time trial (TT). Once methods to enhance the application of NaHCO3 to exercise performance in normoxia were identified, this supplement was then applied to acute hypoxia and recovery. Study 4 investigated the effects of NaHCO3 ingestion on 4 km TT performance at acute moderate hypoxia (~3000 m). Again, both SBC treatments improved performance compared to placebo. The acid base balance recovery profile following exercise was also monitored for 40 min post-exercise, whereby both SBC treatments displayed a similar magnitude of acid base balance recovery compared to a placebo. Study 5 therefore investigated the effects of both SBC2 and SBC3 on repeated 4 km TT (TT1 and TT2) cycling, interspersed by a 40 min recovery at acute moderate hypoxic conditions (~3000 m). Repeated efforts were improved more greatly following SBC3, revealing significant improvements vs. placebo in both TT1 and TT2, and a greater magnitude of effect compared to SBC2. Collectively, these studies highlight the importance of the dose, and timing of NaHCO3 ingestion to improve exercise performance both at normoxia and hypoxia

Date of Award	3 Oct 2018
Original language	English
Awarding Institution	Edge Hill University
Supervisor	LARS MCNAUGHTON (Director of Studies) & STUART SPARKS (Supervisor)