Background By increasing bicarbonate in the blood and removing H+ ions from inside the cells, sodium bicarbonate (NaCO3) supplementation can delay muscular acidosis and improve exercise performance. However, the extent of its effectiveness is unclear.
The study This meta-analysis of randomized controlled trials assessed the effects of NaCO3supplementation on time-trial performance and time to exhaustion in athletes and sports practitioners. The 11 included studies used doses of 0.3–0.4 grams/kg of bodyweight, taken either 60–240 minutes pre-exercise or daily for 3 days before exercise testing.
The results NaCO3 supplementation improved time to exhaustion by 48%, based on 6 studies assessing 85 participants. However, there was no effect on time-trial performance, based on the results from 5 studies assessing 70 participants.
Note The authors noted that none of the studies assessed the effectiveness of supplement blinding by asking participants whether they could correctly identify which supplement was NaCO3 and which was the placebo. Because NaCO3supplementation is associated with gastrointestinal side effects, it's plausible that participants may have known which supplement was sodium bicarbonate. However, the authors did not provide information on gastrointestinal side effects in the included studies.