Beta-alanine supplementation reduces acidosis but not oxygen uptake response during high-intensity cycling exercise.
The oral ingestion of beta-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 beta-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 beta-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 VO(2peak). 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 beta-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 beta-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 beta-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.
Baguet
Audrey
A
Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
Koppo
Katrien
K
Pottier
Andries
A
Derave
Wim
W
D000138:Acidosis / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D000328:Adult; D001784:Blood Gas Analysis; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D013997:Time Factors; D015091:beta-Alanine / Q000008:administration & dosage / Q000494:pharmacology*
D015091:beta-Alanine