Introductionβ-alanine (BAl) and NaHCO3 (SB) ingestion may provide performance benefits by enhancing concentrations of their respective physiochemical buffer counterparts, muscle carnosine and blood bicarbonate, counteracting acidosis during intense exercise. This study examined the effect of BAl and SB co-supplementation as an ergogenic strategy during high-intensity exercise.MethodsEight healthy males ingested either BAl (4.8 g day−1 for 4 weeks, increased to 6.4 g day−1 for 2 weeks) or placebo (Pl) (CaCO3) for 6 weeks, in a crossover design (6-week washout between supplements). After each chronic supplementation period participants performed two trials, each consisting of two intense exercise tests performed over consecutive days. Trials were separated by 1 week and consisted of a repeated sprint ability (RSA) test and cycling capacity test at 110 % Wmax (CCT110 %). Placebo (Pl) or SB (300 mg kgbw−1) was ingested prior to exercise in a crossover design to creating four supplement conditions (BAl-Pl, BAl-SB, Pl–Pl, Pl-SB).ResultsCarnosine increased in the gastrocnemius (n = 5) (p = 0.03) and soleus (n = 5) (p = 0.02) following BAl supplementation, and Pl-SB and BAl-SB ingestion elevated blood HCO3− concentrations (p < 0.01). Although buffering capacity was elevated following both BAl and SB ingestion, performance improvement was only observed with BAl-Pl and BAl-SB increasing time to exhaustion of the CCT110 % test 14 and 16 %, respectively, compared to Pl–Pl (p < 0.01).ConclusionSupplementation of BAl and SB elevated buffering potential by increasing muscle carnosine and blood bicarbonate levels, respectively. BAl ingestion improved performance during the CCT110 %, with no aggregating effect of SB supplementation (p > 0.05). Performance was not different between treatments during the RSA test.

These data are indicative of a largely underappreciated AF prevalence in Australia. They mandate a more systematic effort to both understand and respond to an evolving AF burden.

PurposeExercise at 50–60 % of peak oxygen consumption (VO2 peak) stimulates maximal fat oxidation rates. Despite a lower estimated work performed; high-intensity intermittent exercise (HIIE) training produces greater fat mass reductions when compared with workload-matched continuous (CON) steady state exercise. No metabolic basis has been documented nor mechanisms offered to explain this anomaly. This study investigated the physiological and metabolic responses of two different workload-matched exercise protocols.MethodsOn separate occasions and at least 1 week apart, eight apparently healthy males cycled for 30 min at either 50 % VO2 peak (CON) or performed repeated 20 s bouts of supramaximal exercise at 150 %VO2 peak separated by 40 s rest (HIIE).ResultsThe average heart rate, oxygen consumption, plasma glycerol and free fatty acid concentrations were not different during exercise and recovery between the trials. Plasma lactate and hypoxanthine (Hx) concentrations were elevated and urinary excretion rates of Hx and uric acid were greater following HIIE as compared to CON (P < 0.05).ConclusionExercise-induced plasma Hx accumulation and urinary purine excretion are greater following HIIE and indirectly represents a net loss of adenosine triphosphate (ATP) from the muscle. The subsequent restorative processes required for intramuscular de novo replacement of ATP may contribute to a negative energy balance and in part, account for the potential accelerated fat loss observed with HIIE when compared with CON training programs.

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