Effect of Sodium Bicarbonate on Gastrointestinal Injury During Repeated Sprints in the Heat

Authors

Ozan Kumbasar, University of New Mexico - Main CampusFollow
Jonathan W. Specht, University of Northern IowaFollow
Marissa Ramirez, University of New MexicoFollow
Jennifer Raef, University of New MexicoFollow
Mackenzie Schwartz, University at BuffaloFollow
Alyssa R. Bailly, University of New MexicoFollow
Oscar Chavez Jr., University of New MexicoFollow
Jade X. Dawson, University of New MexicoFollow
Jessica Apodaca, University of New MexicoFollow
Raul Freire, Arizona State UniversityFollow
Withley C. Atkins, University of New MexicoFollow
Flávio de Castro Magalhães, University of New MexicoFollow
Jason Siegler, Arizona State UniversityFollow
Fabiano T. Amorim, University of New MexicoFollow

Abstract

Sodium bicarbonate (SB) is a widely used supplement that can enhance repeat sprint performance; however, a common side effect is gastrointestinal (GI) distress. Exercise in the heat can cause intestinal injury and endotoxemia, but no study has examined whether SB heightens this injury. PURPOSE: To determine whether SB ingestion exacerbates intestinal discomfort, injury, and endotoxemia during repeated sprints in the heat. METHODS: Ten endurance-trained athletes (6 male) completed randomized, counterbalanced, double-blind trials in which they ingested capsules containing SB (0.2 g·kg⁻¹ body mass) or placebo following a high-carbohydrate meal. The trials consisted of a 22-min warm-up followed by four sets of 5 × 6-s maximal standing cycling sprints in 40 °C (dry bulb) heat. Core temperature was continuously recorded. Plasma samples from pre- and post-trial were analyzed for markers of intestinal injury (intestinal fatty acid-binding protein, I-FABP) and endotoxemia (lipopolysaccharide-binding protein, LBP; soluble cluster of differentiation 14, sCD14). GI symptoms were assessed using a questionnaire at three time points: pre-exercise, 10-min into the warm-up, and upon completion of the trial. RESULTS: SB did not alter GI symptoms compared with placebo (p > 0.05). Exercise in the heat increased in I-FABP (time effect: p = 0.03), indicating intestinal injury; however, no condition or interaction effects were observed (p > 0.05). Specifically, I-FABP concentrations increased from 650 ± 481 pg/mL to 941 ± 380 pg/mL in the placebo trial and 439 ± 232 pg/mL to 836 ± 432 pg/mL in the SB trial. LBP and sCD14 concentrations were unaffected by time, condition, and interaction (p > 0.05), suggesting no evidence of endotoxemia. Core temperature increased from pre- to post-exercise in both trials (p < 0.001), but SB had no effect (p = 0.25). Values rose from 36.7 ± 0.3 °C to 38.0 ± 0.4 °C in the placebo trial and from 36.7 ± 0.3 °C to 38.1 ± 0.4 °C in the SB trial. CONCLUSION: SB, when ingested after a high-carbohydrate meal, enhances repeat sprint performance in the heat without increasing heat strain, GI symptoms, intestinal injury, or endotoxemia. These findings indicate that SB taken in this manner is a safe and effective ergogenic aid for high-intensity exercise in the heat without inducing adverse GI health consequences.

Recommended Citation

Kumbasar, Ozan; Specht, Jonathan W.; Ramirez, Marissa; Raef, Jennifer; Schwartz, Mackenzie; Bailly, Alyssa R.; Chavez, Oscar Jr.; Dawson, Jade X.; Apodaca, Jessica; Freire, Raul; Atkins, Withley C.; de Castro Magalhães, Flávio; Siegler, Jason; and Amorim, Fabiano T. (2025) "Effect of Sodium Bicarbonate on Gastrointestinal Injury During Repeated Sprints in the Heat," International Journal of Exercise Science: Conference Proceedings: Vol. 14: Iss. 5, Article 95.
Available at: https://digitalcommons.wku.edu/ijesab/vol14/iss5/95