Effect of combined β-alanine and sodium bicarbonate supplementation on cycling performance


Journal Title (Medline/Pubmed accepted abbreviation): Med. Sci. Sports Exerc.
Year: 2012
Volume:44
Issue: 8
Page numbers: 1545-1551
Summary of background and research design:
Background:  Carnosine is a molecule found in muscle that is made of two amino acids- β-alanine and histidine.  It acts as an intracellular buffer, thereby controlling intra-cellular pH and preserving healthy function of the cell during the stress of exercise.  Habitual supplementation with β-alanine can increase  muscle carnosine concentrations. 
Bicarbonate is a natural buffering system in the blood, and also plays a large role in buffering pH within the cell.  It is thought that, during exercise, a rise in lactate and protons (H+) can accumulate in muscle and can contribute to muscular fatigue.  Buffers can help remove these molecules and allow for greater work to be done.

Hypothesis:  The combination of habitual β-alanine supplementation and one-time bicarbonate supplementation will increase the performance of trained athletes on a maximal cycling trail lasting 4 min.

Subjects:  Highly trained male cyclists (n = 14), age 25.4 ± 7.2 y

Experimental design:  double-blinded, placebo-controlled, randomized, repeated measures

Treatments:
β-alanine- 65 mg/kg body weight per day, divided into 4 doses, taken with meals, or a placebo- dextrose (sugar) in the same dose
Sodium bicarbonate (NaHCO3)- 0.3 g/kg body weight taken with 10 mL/kg of water, or a placebo, were administered after the period of β-alanine supplementation.

Protocol:  The participants were first familiarized with the exercise equipment (a stationary bicycle) and evaluated for oxygen capacity (VO2max), maximum heart rate, and maximum aerobic output.  At a subsequent visit to the laboratory, they completed baseline testing.  Performance testing involved a 9 min warm-up followed by 4 min of maximum output.  Their peak and average power were monitored as well as total work done.  Blood samples were collected before and after exercise.  They then took β-alanine (or the placebo) for 4 weeks.  During the 4 wks of β-alanine supplementation, in order to control training, the participants were asked to complete short duration, high intensity cycling sprints twice per week according to a specific protocol.  They kept a diary of all exercise.  During the 5th week, they reported to the laboratory on 2 occasions separated by 2-4 days.  They ingested either NaHCO3 or a placebo in 6 doses over the span of 60 min.  After a 30 min rest, they completed the same performance testing protocol as at baseline.  Blood samples were acquired before and after NaHCO3 ingestion and after exercise.
Summary of research findings: 
  • The participants that took the placebo for 28 days (instead of β-alanine) performed similarly as at baseline when they took the placebo (instead of NaHCO3).
  • However, the participants that took the placebo instead of β-alanine showed an improvement of about 31% when they consumed the NaHCO3.  In fact, there was a 90% likelihood that NaHCO3 was associated with the observed performance benefit.
  • A small but non-significant effect on performance was seen with β-alanine supplementation in the absence of NaHCO3 (about 1.5% increase in average power and total workload, p = 0.20).
  • Consumption of β-alanine and NaHCO3 led to a significant increase in performance compared to no supplementation.  Six of the seven participants that were taking β-alanine performed better with NaHCO3 than with the placebo.
  • NaHCO3 made the blood more alkaline (less acidic) before exercise compared with the placebo (p < 0.001).
  • Two of the 14 participants reported a slight tingling sensation after taking β-alanine.  Three of the 14 participants reported gastrointestinal discomfort after supplementation with NaHCO3.

Key practice applications:  Supplementation with β-alanine led to a 37% likelihood of increased performance and a 0% likelihood of decreased performance when taken by these highly trained cyclists for 28 days.  NaHCO3 improved their performance to a greater degree.  There was only a small additive effect of β-alanine and NaHCO3. Other studies have found that highly trained athletes have a well-developed buffering capacity and β-alanine supplementation does not improve that capacity much further.  Although the effect of β-alanine appeared to be trivial, that effect may be enough to make a difference in highly competitive races.

Key search terms for this article (5-7 terms): β-alanine, carnosine, buffer, sodium carbonate, baking soda, sprints.
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