Efficacy of sodium bicarbonate ingestion strategies for protecting blinding

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.

Sodium Bicarbonate Ingestion in a Fasted State Improves 16.1-km Cycling Time-Trial Performance

“…To limit the effects of this, participants were fully briefed regarding the ingestion types being specifically designed to limit the GIS response, before the first trial. This, however, remains an inherent issue for the blinding in any ingestion study where GIS may be experienced, but the use of capsules has also been identified as an effective way to maintain blinding in SB studies (35). The choice of not including a familiarization trial is also a limitation; however, the performance of two 16.1-km TT without additional familiarization (over what the participants are used to from training, competition, and previous laboratory testing) has been shown to be very reliable with a coefficient of variation of 0.7% for performance time (25).…”