Beta-alanine fails to improve on 5,000 m running time despite increasing PAT1 expression in long-distance runners.

Background Beta-alanine has become a dietary supplement widely used by athletes due to its ergogenic effect. However, there is still no consensus on the performance benefit of beta-alanine on exercise lasting longer than ten minutes. The present study aimed to evaluate the effect of beta-alanine supplementation on running performance and the expression of TauT and PAT1. Methods This double-blind, randomized study enrolled 16 long-distance runners (37 ± 8 years) who were randomly allocated to two groups: Placebo (PLA) and Beta-alanine (BA) (4.8 g·day-1) for four weeks. Maximal oxygen consumption, anthropometry, body composition, and food intake were determined. Before and after the intervention, the athletes undertook a 5,000 m running time trial. Venous blood (TauT and PAT1 expressions) and ear lobe capillary blood (lactate) collected before and after exercise. Between tests, we monitored the training variables. Results The results were analyzed by T-tests and an ANOVA of repeated measures, with Sidak's post hoc (p Conclusions Although beta-alanine supplementation increased PAT1 expression, there was no statistically significant improvement in 5,000 m running performance. However, individual responses should be considered as the BA showed a higher delta than the PLA.