β-Alanine supplementation reduces acidosis but not oxygen uptake response during high-intensity cycling exercise

• Published in: European journal of applied physiology 2010-02, Vol.108 (3), p.495-503
• Main Authors: Baguet, Audrey, Koppo, Katrien, Pottier, Andries, Derave, Wim
• Format: Article
• Language: English
• Subjects: Acidosis - metabolism; Acidosis - physiopathology; Acidosis - prevention & control; Adult; beta-Alanine - administration & dosage; beta-Alanine - pharmacology; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Blood Gas Analysis; Dietary Supplements; Dose-Response Relationship, Drug; Double-Blind Method; Exercise - physiology; Exercise Test; Fundamental and applied biological sciences. Psychology; Human Physiology; Humans; Male; Muscle, Skeletal - metabolism; Occupational Medicine/Industrial Medicine; Original Article; Oxygen Consumption - drug effects; Oxygen Consumption - physiology; Pulmonary Gas Exchange - physiology; Sports Medicine; Time Factors; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s00421-009-1225-0

The oral ingestion of β-alanine, the rate-limiting precursor in carnosine synthesis, has been shown to elevate the muscle carnosine content. Carnosine is thought to act as a physiologically relevant pH buffer during exercise but direct evidence is lacking. Acidosis has been hypothesised to influence oxygen uptake kinetics during high-intensity exercise. The present study aimed to investigate whether oral β-alanine supplementation could reduce acidosis during high-intensity cycling and thereby affect oxygen uptake kinetics. 14 male physical education students participated in this placebo-controlled, double-blind study. Subjects were supplemented orally for 4 weeks with 4.8 g/day placebo or β-alanine. Before and after supplementation, subjects performed a 6-min cycling exercise bout at an intensity of 50% of the difference between ventilatory threshold (VT) and . Capillary blood samples were taken for determination of pH, lactate, bicarbonate and base excess, and pulmonary oxygen uptake kinetics were determined with a bi-exponential model fitted to the averaged breath-by-breath data of three repetitions. Exercise-induced acidosis was significantly reduced following β-alanine supplementation compared to placebo, without affecting blood lactate and bicarbonate concentrations. The time delay of the fast component (Td 1 ) of the oxygen uptake kinetics was significantly reduced following β-alanine supplementation compared to placebo, although this did not reduce oxygen deficit. The parameters of the slow component did not differ between groups. These results indicate that chronic β-alanine supplementation, which presumably increased muscle carnosine content, can attenuate the fall in blood pH during high-intensity exercise. This may contribute to the ergogenic effect of the supplement found in some exercise modes.