Sodium Bicarbonate and Time-to-Exhaustion Cycling Performance: A Retrospective Analysis Exploring the Mediating Role of Expectation
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Background: Research has shown that ingesting 0.3 g·kg−1 body mass sodium bicarbonate (NaHCO 3) can improve time-to-exhaustion (TTE) cycling performance, but the influence of psychophysiological mechanisms on ergogenic effects is not yet understood. Objective: This study retrospectively examined whether changes in TTE cycling performance are mediated by positive expectations of receiving NaHCO 3 and/or the decline in blood bicarbonate during exercise. Methods: In a randomised, crossover, counterbalanced, double-blind, placebo-controlled design, 12 recreationally trained cyclists (maximal oxygen consumption, 54.4 ± 5.7 mL·kg·min−1) performed four TTE cycling tests 90 min after consuming: (1) 0.3 g·kg−1 body mass NaHCO 3 in 5 mL·kg−1 body mass solution, (2) 0.03 g·kg−1 body mass sodium chloride in solution (placebo), (3) 0.3 g·kg−1 body mass NaHCO 3 in capsules and (4) cornflour in capsules (placebo). Prior to exercise, participants rated on 1–5 Likert type scales how much they expected the treatment they believe had been given would improve performance. Capillary blood samples were measured for acid-base balance at baseline, pre-exercise and post-exercise. Results: Administering NaHCO 3 in solution and capsules improved TTE compared with their respective placebos (solution: 27.0 ± 21.9 s, p = 0.001; capsules: 23.0 ± 28.1 s, p = 0.016). Compared to capsules, NaHCO 3 administered via solution resulted in a higher expectancy about the benefits on TTE cycling performance (Median: 3.5 vs. 2.5, Z = 2.135, p = 0.033). Decline in blood bicarbonate during exercise was higher for NaHCO 3 given in solution compared to capsules (2.7 ± 2.1 mmol·L−1, p = 0.001). Mediation analyses showed that improvements in TTE cycling were indirectly related to expectancy and decline in blood bicarbonate when NaHCO 3 was administered in solution but not capsules. Conclusions: Participants’ higher expectations when NaHCO 3 is administered in solution could result in them exerting themselves harder during TTE cycling, which subsequently leads to a greater decline in blood bicarbonate and larger improvements in performance. Key Points: Ingesting 0.3 g·kg−1 body mass sodium bicarbonate in solution and capsules improved time-to-exhaustion cycling performance Positive expectancy about the benefits of sodium bicarbonate and decline in blood bicarbonate were higher when sodium bicarbonate was administered in solution compared with capsules Improvements in time-to-exhaustion cycling performance for sodium bicarbonate administered in solution were related to expectancy and the enhanced extracellular buffering response
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Both capsule-versus-solution studies provided 0.3 g/kg sodium bicarbonate in solutions and capsules acutely, though Gurton et al. 2023 provided vegetarian capsules while Hilton et al. 2019 used delayed-release capsules.
“Both provided 0.3 g/kg in solutions and capsules acutely, though (W. H. Gurton, Matta, et al. 2023) provided vegetarian capsules while (Hilton et al. 2019) used delayed‐release capsules.”
From Gastrointestinal Symptoms Associated With Sodium Bicarbonate Supplementation Protocols: A Systematic Review (2026) · cites this paper as W. H. Gurton, Matta, et al. 2023
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- Authors
- Gurton, W. H., Matta, G. G., Gough, L. A., Ranchordas, M. K., King, D. G., & Hurst, P.
- Affiliations
- Canterbury Christ Church University (GB)
- Birmingham City University (GB)
- Sheffield Hallam University (GB)
- University of Surrey (GB)
- Corresponding author
- Ranchordas, Mayur Krachna
- ORCID
- Venue
- Sports Medicine - Open
- Published
- 2023-07-31
- Volume
- 9
- Issue
- 1
- Pages
- 65-65
- ISSN
- 2198-9761 (ISSN-L)
- PMC
- PMC10390418
- OpenAlex
- W4385407055
- Cited by
- 15
- References
- 53
- Citations by year
- 2026: 7 · 2025: 2 · 2024: 6
- FWCI
- 4.45
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Locations
- Sports Medicine - Open (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- SHURA (Sheffield Hallam University Research Archive) (Sheffield Hallam University) (acceptedVersion)
- BCU Open Access Repository (Birmingham City University) (acceptedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Topics
- Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
- Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
- Keywords
- sodium bicarbonate, time to exhaustion, cycling performance, ergogenic aids, blood bicarbonate, acid-base balance, mediation analysis, route of administration, recreational cyclists, exercise endurance, psychophysiological mechanisms, capillary blood sampling
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