The effect of sodium bicarbonate mini-tablets ingested in a carbohydrate hydrogel system on 40 km cycling time trial performance and metabolism in trained male cyclists

Abstract

Introduction: Sodium bicarbonate (NaHCO₃) ingestion has been found to be ergogenic in high-intensity exercise that ranges from 1 to 10 min; however, limited studies have investigated high-intensity exercise beyond this duration.

Purpose: The present study aimed to determine the effect of NaHCO₃ ingested using a carbohydrate hydrogel delivery system on 40 km time trial (TT) performance in trained male cyclists.

Methods: Fourteen trained male cyclists ingested 0.3 g kg^-1 BM NaHCO₃ (Maurten AB, Sweden) to determine individualised peak alkalosis, which established time of ingestion prior to exercise. Participants completed a 40 km familiarisation TT, and two 40 km experimental TTs after ingestion of either NaHCO₃ or placebo in a randomised, double-blind, crossover design.

Results: NaHCO₃ supplementation improved performance (mean improvement = 54.14 s ± 18.16 s; p = 0.002, g = 0.22) and increased blood buffering capacity prior to (HCO₃^- mean increase = 5.6 ± 0.2 mmol L^-1, p < 0.001) and throughout exercise (f = 84.82, p < 0.001, pη² = 0.87) compared to placebo. There were no differences in total gastrointestinal symptoms (GIS) between conditions either pre- (NaHCO₃, 22 AU; Placebo, 44 AU; p = 0.088, r = 0.46) or post-exercise (NaHCO₃, 76 AU; Placebo, 63 AU; p = 0.606, r = 0.14).

Conclusion: The present study suggests that ingesting NaHCO₃ mini-tablets in a carbohydrate hydrogel can enhance 40 km TT performance in trained male cyclists, with minimal GIS. This ingestion strategy could therefore be considered by cyclists looking for a performance enhancing ergogenic aid.

Keywords: Alkalosis; Ergogenic aid; Extracellular buffering; High intensity exercise.

Fig. 1

Mean and individual values for total time (A), and mean power (B) following sodium bicarbonate (NaHCO₃) and placebo ingestion. “*” denotes a significant difference between conditions (p < 0.01)

Fig. 2

Mean ± SD split time (A), mean power (B) and mean speed (C). “∞” denotes significant increase from first timepoint (0–10 km) (p < 0.01), “-” denotes significant increase from second timepoint (10–20 km) (p < 0.05), “ = ” denotes significant decrease from third timepoint (20–30 km) (p < 0.05), “#” denotes significant decrease from first timepoint (0–10 km) (p < 0.001), “^” denotes significant decrease from second timepoint (10–20 km) (p < 0.01), and + denotes significant increase from third timepoint (20–30 km) (p < 0.05). “*” denotes a significant condition difference throughout all timepoints (p < 0.01)

Fig. 3

Mean ± SD blood HCO₃⁻ (A) and blood pH (B) responses before and throughout 40 km TT after NaHCO₃ and placebo ingestion. “ + ” denotes significant increase from first time point (baseline) (p < 0.01), “∞” denotes significant decrease from first (pre-exercise) and second (post warm-up) time point (p < 0.01), “-” denotes significant decrease from second time point (pre-exercise) (p = 0.01), “ = ” denotes significant increase from fourth time point (10 km) (p < 0.05), “#” denotes significant decrease from sixth time point (30 km) (p < 0.005), “*” denotes a significant condition difference between NaHCO₃ and placebo conditions (p < 0.01)

Fig. 4

Mean ± SD VCO₂ (A), VO₂ (B), RER (C), heart rate (D), blood lactate (E), and RPE (F) responses throughout 40 km TT after NaHCO₃ and placebo ingestion. “^” denotes significant decrease from first timepoint (9-10 km) (p < 0.05). “#” denotes significant increase from first timepoint (10 km) (p < 0.001). “+” denotes significant increase from second timepoint (20 km) (p < 0.01). “-” denotes significant increase from third timepoint (30 km) (p < 0.01). “*” denotes significant condition difference at all timepoints (p < 0.01)