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

William H Gurton; Lewis A Gough; S Andy Sparks; Mark A Faghy; Katharine E Reed

doi:10.3389/fnut.2020.00154

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

Front Nutr. 2020 Sep 8:7:154. doi: 10.3389/fnut.2020.00154. eCollection 2020.

Authors

William H Gurton¹, Lewis A Gough², S Andy Sparks³, Mark A Faghy⁴, Katharine E Reed¹

Affiliations

¹ School of Sport, Rehabilitation and Exercise Science, University of Essex, Colchester, United Kingdom.
² Research Centre for Life and Sport Sciences (CLaSS) School of Health Sciences, Birmingham City University, Birmingham, United Kingdom.
³ Sports Nutrition and Performance Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, United Kingdom.
⁴ Human Sciences Research Centre, University of Derby, Derby, United Kingdom.

Abstract

This study investigated the effects of two sodium bicarbonate (NaHCO₃) 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^-1) 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^-1 BM NaHCO₃ (SBC2), 0.3 g.kg^-1 BM NaHCO₃ (SBC3), or 0.07 g.kg^-1 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; p = 0.045) and SBC3 (+31.9 s; p = 0.004) compared to PLA. Glycolytic contribution increased, albeit non-significantly, during the TTE protocol for SBC2 (+7.77 kJ; p = 0.10) and SBC3 (+7.95 kJ; p = 0.07) compared to PLA. GI upset was exacerbated post-exercise after SBC3 for nausea compared to SBC2 and PLA (p < 0.05), whilst SBC2 was not significantly different to PLA for any symptom (p > 0.05). Both NaHCO₃ doses enhanced cycling performance and glycolytic contribution, however, higher doses may maximize ergogenic benefits.

Keywords: alkalosis; anaerobic; ergogenic aid; extracellular buffer; fatigue; high-intensity exercise.