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Randomized Controlled Trial
. 2022 Dec;122(12):2555-2563.
doi: 10.1007/s00421-022-05031-0. Epub 2022 Sep 2.

Efficacy of sodium bicarbonate ingestion strategies for protecting blinding

William H Gurton  1   2 , Guilherme G Matta  1 , Lewis A Gough  3 , Philip Hurst  1
Affiliations
Randomized Controlled Trial

Efficacy of sodium bicarbonate ingestion strategies for protecting blinding

William H Gurton et al. Eur J Appl Physiol. 2022 Dec.

Abstract

Sodium bicarbonate (NaHCO3) is a widely researched ergogenic aid, but the optimal blinding strategy during randomised placebo-controlled trials is unknown. In this multi-study project, we aimed to determine the most efficacious ingestion strategy for blinding NaHCO3 research. During study one, 16 physically active adults tasted 0.3 g kg-1 body mass NaHCO3 or 0.03 g kg-1 body mass sodium chloride placebo treatments given in different flavour (orange, blackcurrant) and temperature (chilled, room temperature) solutions. They were required to guess which treatment they had received. During study two, 12 recreational athletes performed time-to-exhaustion (TTE) cycling trials (familiarisation, four experimental). Using a randomised, double-blind design, participants consumed 0.3 g kg-1 body mass NaHCO3 or a placebo in 5 mL kg-1 body mass chilled orange squash/water solutions or capsules and indicated what they believed they had received immediately after consumption, pre-TTE and post-TTE. In study one, NaHCO3 prepared in chilled orange squash resulted in the most unsure ratings (44%). In study two, giving NaHCO3 in capsules resulted in more unsure ratings than in solution after consumption (92 vs 33%), pre-TTE (67 vs. 17%) and post-TTE (50 vs. 17%). Administering NaHCO3 in capsules was the most efficacious blinding strategy which provides important implications for researchers conducting randomised placebo-controlled trials.

Keywords: Dietary supplements; Double-blind; Research methods; Sports nutrition.

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Conflict of interest statement

W.H.G., G.G.M., L.A.G., and P.H. can confirm that there are no competing interests related to the study outcome or the supplement investigated.

Figures

Fig. 1
Fig. 1
A–B Median and individual responses for palatability (A) and how likely to use (B) scores for NaHCO3 and placebo from study 2. Note: SB-SOL = NaHCO3 in solution; SB-CAP = NaHCO3 in capsules; PL-SOL = placebo in solution; PL-CAP = placebo in capsules. *SB-SOL vs. SB-CAP, PL-SOL & PL-CAP (p < 0.05)
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