Effects of Beta-alanine Supplementation and High Intensity Interval training among Recreationally Active Females

Beta-alanine is a non-essential amino acid that when combined with L-histidine forms the dipeptide carnosine. Recent research has shown that supplementary intake of beta-alanine can substantially increase carnosine content in muscle fibers and has been associated with attenuating fatigue and enhancing high intensity exercise performance. The aim of this study was to examine the effects of 4 weeks of beta-alanine supplementation combined with high intensity interval training (HIIT) on indices of aerobic and anaerobic performance, rowing performance, and body composition. Twenty-one recreationally active females (22.2 ± 2.2 yrs.) participated in a double blind, placebo controlled study and were randomly assigned to one of 3 groups: beta-alanine (BA, n = 8), placebo (PLA, n = 7), or control (CON, n = 6). Prior to and following 4 weeks of supplementation all groups had anthropometric measurements done and body composition was determined using dual energy x-ray absorptiometry (DEXA). Participants also performed a graded exercise test on the rowing ergometer to determine VO2 peak, ventilatory threshold (VT), and time to exhaustion (TTE). Additionally, participants came back to the lab to complete a 1,000 m time trial (TT) to determine time for completion and peak power output (PPO). During the 4 week intervention the BA and PLA groups completed a 7 minute 1: 1 (work: recovery) HIIT protocol that was a pre-determined workload whilst consuming either 6.4 g/day of BA or PLA. All three groups showed significant improvements from pre to post testing in VO2 peak, TTE, VT, TT, PPO and a reduction in total BF% in arms (p ≤ 0.05). While several of the variables had significant interactions between groups: VO2 peak, TTE, TT, PPO, BF% legs, and BF% trunk, (p ≤ 0.05), post hoc testing revealed that peak power output was the only the variable that showed a significant difference between the BA and PLA groups as compared to the CON group during post testing (p = 0.00). The results of this study suggest that HIIT can enhance measures of aerobic capacity and increase PPO, while beta-alanine supplementation did not seem to have much of an effect on training