Comparison between acute effects of β-alanine supplementation on psychophysiological scales, blood lactate, training impulse and heart rate variability during high-intensity functional training

The aim of the present study was to evaluate the effects of acute β-alanine supplementation on the rate of perceived exertion, training impulse and heart rate variability during high intensity functional training. Twelve trained men (age: 22.0 ± 5.0 years old; body mass index: 23.6 ± 4.2 Kg/m2; fat mass: 9.8 ± 2.3; VO2max: 54.0 ± 4.5 mL/kg/min) participated in the present study. At the first visit to the training center, they performed a cardiopulmonary exercise test in the rowing ergometer to determine the maximum oxygen consumption. At the two subsequent visits, participants were randomized as-signed to the following conditions: a) placebo supplementation and b) 6.4g of β-alanine supple-mentation. The training protocol adopted was to execute the maximal number of repetitions of 5 pull-ups, 10 push-ups, and 15 squats per round in 20 minutes. Simultaneously, the following training load parameters were measured and then also compared during the two experimental conditions: session load (SL), training impulse (TRIMP), blood lactate concentration (BLC) and heart rate variability (HRV). β-alanine supplementation increased performance (p <0.05) and reduced BLC (p <0.05). Additionally, the internal training load parameters showed strong correlations with performance after β-alanine supplementation (SL: r=0.80, p <0.01; TRIMP: r=0.80, p <0.01; and HRV: r=0.79, p <0.01). Therefore, β-alanine supplementation may increase performance in high intensity functional fitness training.