This study, published in the European Journal of Sport Science, investigates the effects of sodium bicarbonate (SB) supplementation on performance and physiological responses in well-trained cyclists. The randomized controlled trial involved 24 participants, including 15 males and 9 females, with a maximal oxygen uptake (V˙O2 max) of 72 ± 5 mL·min-1·kg-1 for males and 57 ± 6 mL·min-1·kg-1 for females.
Participants underwent a screening and familiarization session before two experimental sessions in a double-blind, crossover design. They ingested SB (approximately 0.26 g·kg-1) or a placebo two hours prior to the experimental sessions. Each session included a step-test protocol followed by five high-intensity interval training (HIT) bouts, consisting of three 40-second maximal efforts with 60 seconds of recovery, and four 30-second Wingate sprints.
The results indicated that during HIT bouts, power output (PO) was significantly higher in the SB condition, with a mean difference of 8.1 ± 22.1 W (p = 0.045). Additionally, oxygen uptake was increased by 60.1 ± 124.7 mL·min-1 (p = 0.006), and the time spent above 90% V˙O2 max was greater by 23.7 ± 52.6 seconds (p = 0.012). In the Wingate sprints, cyclists also demonstrated significantly greater PO following SB ingestion, with a mean difference of 11.6 ± 26.8 W (p = 0.002).
Moreover, the study found that SB supplementation led to higher blood levels of bicarbonate, pH, and lactate (all p < 0.001). However, cycling economy and fractional utilization of V˙O2 max were unaffected by SB supplementation (p = 0.977 and p = 0.818, respectively).
In conclusion, SB supplementation appears to enhance power output and time spent above 90% V˙O2 max during high-intensity interval training and improves performance in repeated Wingate sprints. However, the long-term adaptations, such as improvements in V˙O2 max and sprint performance, require further investigation.
What this study does not show
This study does not demonstrate whether sodium bicarbonate supplementation leads to long-term improvements in overall athletic performance or adaptations in V˙O2 max.
Evidence scorecard
- Analytic validity: established
- Clinical validity: established
- Clinical utility: partial
The evidence is based on a randomized controlled trial involving human participants.