title: Six weeks of high-intensity interval training with and without beta-alanine supplementation for improving cardiovascular fitness in women.
abstract: The purpose of the present study was to evaluate the effects of cycle ergometry high-intensity interval training (HIIT) with and without beta-alanine supplementation on maximal oxygen consumption rate (VO2 peak), cycle ergometer workload at the ventilatory threshold (VT W), and body composition. Forty-four women (mean +/- SD age = 21.8 +/- 3.7 years; height = 166.5 +/- 6.6 cm; body mass (BM) = 65.9 +/- 10.8 kg; VO2 peak = 31.5 +/- 6.2 ml x kg(-1) x min(-1)) were randomly assigned to 1 of 3 groups: beta-alanine (BA, n = 14) 1.5 g + 15 g dextrose powder; placebo (PL, n = 19) 16.5 g dextrose powder; or control (CON, n = 11). Testing was conducted at baseline (week 0), after 3 weeks (week 4), and after 6 weeks (week 8). VO2 peak (ml x kg(-1) x min(-1)) and VT W were measured with a metabolic cart during graded exercise tests on a corival cycle ergometer, and body composition (percent fat = % fat and fat-free mass = FFM) were determined by air displacement plethysmography. High-intensity interval training was performed on a corival cycle ergometer 3 times per week with 5 2-minute work intervals and 1-minute passive recovery with undulating intensities (90-110% of the workload recorded at VO2 peak) during each training session. VO2 peak increased (p <or= 0.05) in the BA and PL groups at weeks 4 and 8, but did not change (p > 0.05) for the CON group. VT W increased (p <or= 0.05) for all groups at weeks 4 and 8. Body mass increased (p <or= 0.05) only for the BA group at weeks 4 and 8, whereas %fat decreased (p <or= 0.05) and FFM increased (p <or= 0.05) at weeks 4 and 8 for all groups (BA, PL, and CON). Although it is unclear why beta-alanine supplementation increased BM, there was no additive effects for increasing VO2 peak beyond the PL. Overall, these results suggested that HIIT may be an effective and time-efficient method of training to improve maximal oxygen uptake.
authors.affiliation: Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma, USA.
authors.forename: Ashley A
authors.initials: AA
authors.lastname: Walter
authors.forename: Abbie E
authors.initials: AE
authors.lastname: Smith
authors.forename: Kristina L
authors.initials: KL
authors.lastname: Kendall
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Stout
authors.forename: Joel T
authors.initials: JT
authors.lastname: Cramer
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold; D001642:Bicycling / Q000502:physiology*; D001823:Body Composition; D019587:Dietary Supplements; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D006801:Humans; D010101:Oxygen Consumption; D010806:Physical Education and Training / Q000379:methods*; D010807:Physical Endurance; D010809:Physical Fitness; D015091:beta-Alanine / Q000494:pharmacology*
chemical_list: D015091:beta-Alanine