San Clemente, CA. FIK, JH, and AW served as scientific consultants for StemTech International. Authors’ contributions

CAR, JH, FIK, and AW contributed to the study conception and design, SDR and JM screened the subjects and provided medical oversight, CAR, JYW acquired the data, JP performed the data analysis, CAR, JH, FIK, and AW interpreted the data; All authors were involved in drafting the manuscript and have given final approval of the published version.”
“Introduction Alkalizing agents have been used in high performance sports as a strategy to postpone the SYN-117 mw onset of fatigue during high intensity exercise by slowing the decline in muscle and blood pH [1, 2]. Studies have confirmed that increasing the extracellular pH, via an alkalizer, promotes the

efflux of lactate mTOR inhibitor and H+ from the active muscles [1, 3–5]. Therefore, artificially inducing alkalosis prior to anaerobic exercise may reduce intracellular acidosis and increase the time to fatigue [6, 7] The process known as “bicarbonate loading”, in which sodium bicarbonate is ingested pre-performance, is a popular method of blood alkalization among athletes [6, 8]. According to a recent meta-analysis by Carr et al. [8], sodium bicarbonate enhances performance by 1.7% (±2.0%) for a 60 sec maximal effort, with a dose of 0.3 g kg-1 of body mass being the optimal dose. However, the gastrointestinal (GI) acceptance profile of sodium bicarbonate ADP ribosylation factor is narrow and 10% of humans cannot adequately tolerate the doses needed to elicit an ergogenic effect [6, 9].

Thus, ingesting sodium bicarbonate in high enough doses to induce an adequate modification of the acid–base balance during exercise can be detrimental to performance [6, 9, 10]. Sodium citrate (Na-CIT) is another alkalizing agent that has been studied in sports over a broad array of doses, times and distances but the results on its ergogenic effect have been inconclusive [2–4, 10–14]. Indeed, the meta-analysis by Carr et al. [8] reported an unclear effect on performance (0.0 ± 1.3%) for a 60 sec maximal effort, with a dose of 0.5 g kg-1. Due to this uncertainty, in combination with its lower commercial availability, STI571 mouse Na-CIT has not been used as an alternative to sodium bicarbonate although it has a higher GI tolerance [2, 5, 6]. Na-CIT can enter the sarcolemma through a recently discovered plasma membrane citrate transporter [15], providing new evidence to support its potential effect on performance. Competitive swimming is an ideal model for studying the effectiveness of alkalizing agents due to its high reliance on anaerobic metabolism. Events range in duration from 22 sec (50 m freestyle) to 15 min (1500 m freestyle) with the highest blood lactate concentrations found in the 200 m (~2 min) events. Typical post-race blood lactate concentrations for these events are 6.4, 9.1, and 14.