AUTHOR=Gurton William H. , Gough Lewis A. , Sparks S. Andy , Faghy Mark A. , Reed Katharine E. 

TITLE=Sodium Bicarbonate Ingestion Improves Time-to-Exhaustion Cycling Performance and Alters Estimated Energy System Contribution: A Dose-Response Investigation

JOURNAL=Frontiers in Nutrition

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2020.00154

DOI=10.3389/fnut.2020.00154

ISSN=2296-861X

ABSTRACT=<p>This study investigated the effects of two sodium bicarbonate (NaHCO<sub>3</sub>) doses on estimated energy system contribution and performance during an intermittent high-intensity cycling test (HICT), and time-to-exhaustion (TTE) exercise. Twelve healthy males (stature: 1.75 ± 0.08 m; body mass: 67.5 ± 6.3 kg; age: 21.0 ± 1.4 years; maximal oxygen consumption: 45.1 ± 7.0 ml.kg.min<sup>−1</sup>) attended four separate laboratory visits. Maximal aerobic power (MAP) was identified from an incremental exercise test. During the three experimental visits, participants ingested either 0.2 g.kg<sup>−1</sup> BM NaHCO<sub>3</sub> (SBC2), 0.3 g.kg<sup>−1</sup> BM NaHCO<sub>3</sub> (SBC3), or 0.07 g.kg<sup>−1</sup> BM sodium chloride (placebo; PLA) at 60 min pre-exercise. The HICT involved 3 × 60 s cycling bouts (90, 95, 100% MAP) interspersed with 90 s recovery, followed by TTE cycling at 105% MAP. Blood lactate was measured after each cycling bout to calculate estimates for glycolytic contribution to exercise. Gastrointestinal (GI) upset was quantified at baseline, 30 and 60 min post-ingestion, and 5 min post-exercise. Cycling TTE increased for SBC2 (+20.2 s; <italic>p</italic> = 0.045) and SBC3 (+31.9 s; <italic>p</italic> = 0.004) compared to PLA. Glycolytic contribution increased, albeit non-significantly, during the TTE protocol for SBC2 (+7.77 kJ; <italic>p</italic> = 0.10) and SBC3 (+7.95 kJ; <italic>p</italic> = 0.07) compared to PLA. GI upset was exacerbated post-exercise after SBC3 for nausea compared to SBC2 and PLA (<italic>p</italic> &lt; 0.05), whilst SBC2 was not significantly different to PLA for any symptom (<italic>p</italic> &gt; 0.05). Both NaHCO<sub>3</sub> doses enhanced cycling performance and glycolytic contribution, however, higher doses may maximize ergogenic benefits.</p>