Enteric-coated sodium bicarbonate supplementation improves high-intensity cycling performance in trained cyclists

Abstract

Purpose Enteric-coated sodium bicarbonate (NaHCO 3) can attenuate gastrointestinal (GI) symptoms following acute bicarbonate loading, although the subsequent effects on exercise performance have not been investigated. The purpose of this study was to examine the effects of enteric-coated NaHCO 3 supplementation on high-intensity exercise performance and GI symptoms. Methods Eleven trained male cyclists completed three 4 km time trials after consuming; a placebo or 0.3 g•kg-1 body mass NaHCO 3 in enteric-coated or gelatin capsules. Exercise trials were timed with individual peak blood bicarbonate ion concentration ([HCO 3-]). Blood acid-base balance was measured pre-ingestion, pre-exercise, and post-exercise, whereas GI symptoms were recorded pre-ingestion and immediately pre-exercise. Results Pre-exercise blood [HCO3 − ] and potential hydrogen (pH) were greater for both NaHCO 3 conditions (P < 0.0005) when compared to placebo. Performance time was faster with enteric-coated (− 8.5 ± 9.6 s, P = 0.044) and gelatin (− 9.6 ± 7.2 s, P = 0.004) NaHCO 3 compared to placebo, with no significant difference between conditions (mean difference = 1.1 ± 5.3 s, P = 1.000). Physiological responses were similar between conditions, although blood lactate ion concentration was higher with gelatin NaHCO 3 (2.4 ± 1.7 mmol•L-1 , P = 0.003) compared with placebo. Furthermore, fewer participants experienced GI symptoms with enteric-coated (n = 3) compared to gelatin (n = 7) NaHCO 3. Discussion Acute enteric-coated NaHCO 3 consumption mitigates GI symptoms at the onset of exercise and improves subsequent 4 km cycling TT performance. Athletes who experience GI side-effects after acute bicarbonate loading may, therefore, benefit from enteric-coated NaHCO 3 supplementation prior to exercise performance.

Does varying the ingestion period of sodium citrate influence blood alkalosis and gastrointestinal symptoms?

“…Delayed-release or enteric-coated capsules have been reported to delay the occurrence of peak blood alkalosis when compared to gelatine capsules (by approx. 20-24 min [43,44]) in a similar fashion to that seen when comparing the 15 and 60 min ingestion periods in the current investigation (by approx. 20 min).…”

Sodium Bicarbonate Ingestion Improves Time-to-Exhaustion Cycling Performance and Alters Estimated Energy System Contribution: A Dose-Response Investigation

“…McNaughton (17) reported exacerbated GI upset following higher NaHCO 3 doses, while Gough et al (12) observed reduced occurrence of bowel urgency and bloating for 0.2 g.kg −1 compared to 0.3 g.kg −1 BM NaHCO 3 . Reducing the dose is a simple strategy that might remove some of the negative connotations of ingesting this supplement, whilst it is far more cost effective than some of the recent strategies employed to reduce the GI upset following NaHCO 3 ingestion, such as in enteric-coated capsules (18,19).…”

Capsule Size Alters the Timing of Metabolic Alkalosis Following Sodium Bicarbonate Supplementation

“…There is, however, a suggestion that encapsulation may impair or slow down bicarbonate availability through decreased gut transit time (16) changing the optimal pre-exercise ingestion time. Additionally, while the gastro-resistant properties of different capsule forms and their subsequent effects on bicarbonate bioavailability have begun to be elucidated (10,13,17), the effects of the physical properties of capsules, such as their overall size (and therefore surface area), on bicarbonate bioavailability remain unclear.…”