Research Review By Christopher Howard©

Date Posted:

July 2009

Study Title:

Effects of ß-alanine supplementation and high-intensity interval training on endurance performance and body composition in men; a double-blind trial

Authors:

Smith AE, Walter AA, Graef JL et al.

Author's Affiliations:

Metabolic and Body Composition Laboratory & Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA.

Publication Information:

Journal of the International Society of Sports Nutrition 2009; 6:5.

Background Information:

High intensity exercise uses adenosine triphosphate (ATP), phosphocreatine (PCr) and glycogenic substrates resulting in accumulation of adenosine diphosphate (ADP), inorganic phosphate (Pi), and hydrogen ions (H+). Excessive hydrogen ion accumulation decreases intramuscular pH, which may contribute to fatigue. Therefore, it is reasonable to assume that increasing one’s ability to buffer hydrogen ions may delay fatigue. The majority of ion buffering occurs by the bicarbonate (HCO3-) system, however when exercise is of higher intensity, the ability of the bicarbonate system to buffer hydrogen ions is exceeded. In these situations, the ability of carnosine to buffer hydrogen ions becomes increasingly important. Carnosine is synthesized in muscle from ß-alanine and histidine and its production is limited by the availability of ß-alanine. To increase muscle carnosine levels, supplementation with ß-alanine has been suggested. To date, supplementation with ß-alanine has been shown to increase performance (1), and is associated with an increase in total volume of work (2).

High intensity interval training (HIIT) involves bouts of supra-maximal exercise interspersed with rest at predetermined ratios (commonly 2:1 work:rest). HIIT does not appear to increase skeletal muscle carnosine content, however such training has been theorized to improve muscle buffering capacity. To date, no study has looked at the effect of HIIT in combination with ß-alanine supplementation. Therefore the purpose of this study was to look at the effects of chronic ß-alanine supplementation in combination with HIIT on endurance performance in recreationally trained individuals.

Pertinent Results:

  • Overall, HIIT was an effective training method to significantly improve aerobic performance measures in this group of recreationally active men
  • ß-alanine supplementation seemed to enhance the benefits of HIIT
  • Both treatment groups had an increase in VO2peak during the first 3-week training period, but only the ß-alanine supplemented group saw an increase in the second 3-week training period.
  • Regarding VO2TTE (time to fatigue) – both groups demonstrated pre- to mid-test differences, with no difference between groups. Only the ß-alanine supplemented group had a significant difference from mid- to post-testing (p = 0.043).
  • Ventilatory Threshold was not significantly different between groups. Improvements from pre- to mid-testing were not significant in either group. The placebo group showed improvement from mid- to post-testing.
  • The ß-alanine group consistently trained at higher workloads and for a longer amount of time than the PL group, however this was not statistically significant.
  • Body mass did not change significantly in either group, but lean body mass was significantly increased from pre- to mid-testing in the ß-alanine group.
  • There were no significant differences with regards to the dietary intake and analyses of the two groups.

Clinical Application & Conclusions:

Based on the findings of this study, it appears that HIIT (2:1 work:rest) is an effective training method for improving VO2peak, time to exhaustion, and total work done over a 6-week cycle. Also, based on the findings of this study, it appears that ß-alanine supplementation is effective when combined with HIIT in improving the previously mentioned variables.

In addition, ß-alanine supplementation was more beneficial in creating improvements during the second 3-week training period. It is important to realize that this study was completed using relatively untrained men. Therefore, recommendations to use ß-alanine in conjunction with HIIT need to be made in light of this limitation.

Study Methods:

Subjects: 46 college aged men (average age 22) who were recreationally active 1-5 hours per week participated in this study. Subjects had not taken sports supplement in past 6 months.

Study Design:
  • Double blind, randomized study
  • Two 3-week periods of HIIT & ß-alanine supplementation
  • The first 3-week training period was completed at 90-110% of VO2peak, the second 3-week period peaked at 115%.
  • All participants completed baseline, mid-, and post- testing
  • All participants performed a continuous graded exercise test on an electrically braked cycle ergometer (Corval 400, Goningen, The Netherlands) to determine VO2peak, time to exhaustion (VO2TTE), and ventilatory threshold (VT)
  • Pedal cadence was maintained at 70rpm, while power output was initiated at 50W for a five minute warm-up. Power Output was increased 25W every two minutes until the participant could no longer maintain a cadence above 60rpm.
  • Respiratory gases were analyzed breath by breath (True One 2400 Metabolic Measurement System, Parvo-Medics Inc., Provo UT) to determine VO2peak and VT.
  • Heart Rate was also monitored (Polar FS1, Polar Electro Inc. Lake Success, NY)
  • VO2TTE was measured in seconds on an electrically braked cycle ergometer at a cadence of ~70rpm. A five-minute warm up at 50W was preformed followed by a cycle to exhaustion at 110% of maximum VO2peak workload. TTE was the time that cadence could be maintained above 60rpm.
  • TWD was calculated using the equation: TTE(s) x Power Output (W) / 1000. This value was presented in kilojoules (kJ).
  • Diet records were kept to evaluate changes in kcal/protein intake – subjects were encouraged to maintain their usual diets during the study period
  • Body composition was taken using air displacement plethysmography (Bod Pod) using the formula of Brozek et. al.
  • Separate two-way repeated measures ANOVAs were used to identify any group by time interactions.
Training Design:
  • Training was completed 3-days per week beginning at 90% of maximum power output (W) and progressing to 115% by the end of the second 3-week training period.
  • The first 3-week period consisted of 5 sets of two-minute training intervals followed by one-minute rest intervals. The second 3-week training period was similar to the first 3-week training period, but one session in weeks 5 & 6 consisted of six sets of two-minute work intervals followed by one-minute rest intervals.
Supplementation Protocol:
  • Supplementing groups – placebo vs. ß-alanine supplementation, both performed HIIT
  • 6g ß-alanine (1.5g ß-alanine, 15g dextrose per dose) or placebo (16.5g dextrose per dose) during first 3-weeks, 3g ß-alanine (1.5g ß-alanine, 15g dextrose per dose) or placebo (16.5g dextrose per dose) during second 3-weeks
  • On training days, subjects consumed one dose 30 minutes pre-exercise and one-dose immediately post exercise. The remaining two doses were taken at random time points chosen by the subject.

Study Strengths / Weaknesses:

This study controlled for obvious influences that often remain uncontrolled in other studies. The use of diet logs, while limited, is still useful. In addition, intake of supplements was logged and supplementation pre- and post-exercise was controlled by the examiners. HIIT design and supplementation design was good. Future studies are needed to tease out the most effective doses of ß-alanine for this type of training.

Additional References:

  1. Hill CA, Harris RC, Kim HJ, Harris BD, Sale C, Boobis LH, Kim CK, Wise JA: Influence of beta-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycyling capacity. Amino Acids 2007. 32(2): 225-233.
  2. Hoffman J, Ratamess N, Faigenbaum A, Ross R, Kang J, Stout J, Wise JA: Short-duration beta-alanine supplementation increases training volume and reduces subjective feelings of fatigue in college football players. Nutrition Research 2007, 28(1):31-35.