title: The effects of beta-alanine supplementation on physical working capacity at heart rate threshold.
abstract: Beta-alanine (BA) supplementation has been shown to delay neuromuscular fatigue as a result of increased muscle carnosine concentrations. Carnosine has also been found in brain and cardiac tissue. The physical working capacity test at heart rate threshold (PWC(HRT)) is a global estimate of the onset of fatigue during exercise, influenced by central and peripheral factors. The purpose of this study was to determine the effects of 28 days of BA supplementation on the PWC(HRT). Thirty subjects (mean ± SD; age: 21·0 ± 2·1 years; body mass: 72·7 ± 14·5 kg; height: 170·1 ± 7·9 cm) were randomly assigned to BA (n = 15) or placebo (PL, n = 15) groups. Testing included eight to nine total visits: an enrolment day, physical screening, peak oxygen consumption (V(·)O(2peak)) and two PWC(HRT) assessments over 4 days. Significant differences existed between BA and PL for PWC(HRT) (P = 0·001; mean∆: BA∆ = +24·2 watts, PL∆ = +11·2 watts), but not for V(·)O(2peak) (P = 0·222), time to exhaustion (TTE; P = 0·562) or ventilatory threshold (VT; P = 0·134). Results suggest that BA may increase heart rate training threshold. These results, in combination with one previous study reporting a potential effect of BA on HR, suggest that future studies should evaluate both central and peripheral aspects of fatigue with BA intake.
authors.affiliation: Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Abbie E
authors.initials: AE
authors.lastname: Smith-Ryan
authors.forename: Mary N
authors.initials: MN
authors.lastname: Woessner
authors.forename: Malia N
authors.initials: MN
authors.lastname: Melvin
authors.forename: Hailee L
authors.initials: HL
authors.lastname: Wingfield
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Hackney
mesh_terms: D000328:Adult; D019587:Dietary Supplements; D004334:Drug Administration Schedule; D017079:Exercise Tolerance / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D018763:Muscle Fatigue / Q000187:drug effects; D053580:Muscle Strength / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D009657:North Carolina; D010101:Oxygen Consumption / Q000187:drug effects; D013997:Time Factors; D016896:Treatment Outcome; D015091:beta-Alanine / Q000008:administration & dosage*
chemical_list: D015091:beta-Alanine
keywords: aerobic exercise; carnosine; clinical evaluation; ergogenic aid; pH