Negligible benefit of oral single-dose sodium bicarbonate on continuous running performance: systematic review with meta-analysis of randomized, double-blind, placebo-controlled trials.

After adjusting for GI-related study withdrawals and publication bias, the treatment effect of sodium bicarbonate on continuous running performance was negligible and not statistically significant.

• SMD = 0.18; 95% CI: -0.01, 0.36; p = 0.06; I² = 0%; moderate certainty evidence
• The SMD of 0.18 falls in the 'negligible benefit' range (0.00–0.19) as defined by the authors
• Analysis included 11 studies with 126 participants, all using a cross-over design
• Random-effects meta-analysis was used with trim-and-fill method for publication bias adjustment and intent-to-treat methods for GI-related withdrawals

In studies enrolling males only, the treatment effect of sodium bicarbonate on running performance was small and statistically significant.

• SMD = 0.40; 95% CI: 0.18, 0.63; p < 0.001 in the 8 studies that enrolled males only
• An SMD of 0.40 falls in the 'small benefit' range (0.20–0.49) as defined by the authors
• 84% of subjects across all included studies were male
• In meta-regression, male sex was associated with greater SB performance benefits (p = 0.03)

Gastrointestinal symptoms occurred significantly more frequently with sodium bicarbonate supplementation than with placebo.

• GI symptoms occurred in 29.5% of SB participants vs. 2.6% of placebo participants
• Odds ratio = 5.9; p = 0.003; low certainty evidence
• GI-related study withdrawal rates were 8.7% with SB vs. 1.6% with placebo
• GI-related withdrawal odds ratio = 2.9; p = 0.049; moderate certainty evidence

Higher body mass was associated with greater sodium bicarbonate performance benefits in meta-regression.

• Higher body mass was significantly associated with greater SB performance benefits (p = 0.04) in univariable meta-regression
• Male sex (p = 0.03) and higher body mass (p = 0.04) were the two factors identified in meta-regression as associated with treatment effect magnitude
• Meta-regression was univariable in design

The included studies had specific characteristics regarding dosing, participant demographics, and test duration.

• Typical SB dose was 0.3 g/kg body weight
• Performance test durations ranged from 1 to 30 minutes with a median of 4 minutes
• All 11 studies used a cross-over design
• Most (84%) subjects were male across the 11 studies comprising 126 participants
• Studies were published through 31 December 2024 and identified via Medline, Embase, and Cochrane Central Register of Controlled Trials