Improved training tolerance by supplementation with α-Keto acids in untrained young adults: a randomized,double blind,placebo-controlled trial

Background: exercise causes a variety of physiological and metabolic changes that can in turn reduce exercise tolerance. one of the potential mechanisms responsible for fatigue is exercise-induced hyperammonemia . previous studies have shown that supplementation with amino acids can increase training tolerance. the α-keto acids are biochemical analogs of amino acids and can be converted to amino acids through transamination,thus reducing the cellular ammonia level. this double blind,placebo-controlled study was designed to investigate the effects of α-keto acid supplementation (kas) on training tolerance,training effect,and stress-recovery state.methods: thirty-three untrained young male adults underwent four weeks of training (5 sessions/week; 30 minutes running at the individual anaerobic threshold followed by 3 x 3 minute sprints/each session). throughout the 4 weeks of training and one week of recovery,subjects took α-ketoglutarate (akg group,0.2 g/kg/d,n = 9),branched-chain keto acids (bcka group,0.2 g/kg/d,n = 12) or isocaloric placebo (control group,n = 12) daily.results: the 4 th week training volume,maximum power output and muscle torque were higher in the akg group (175 ± 42 min,412 ± 49 watts and 293 ± 58 newton meters,respectively,p<0.05) and the bcka group (158 ± 35,390 ± 29 and 273 ± 47,p<0.05) than in the control group (92 ± 70,381 ± 67 and 233 ± 43). the general stress and emotional exhaustion as assessed by the rest-stress-questionnaire-sport after the 3 rd week of training increased significantly in the control group (p<0.05),but not in the kas groups.conclusions: under kas,subjects could bear a higher training volume and reach a higher power output and peak muscle torque,accompanied by a better stress-recovery-state. thus,kas improves exercise tolerance and training effects along with a better stress-recovery state. whether the improved training tolerance by kas is associated with effects on ammonia homeostasis requires further observation. © 2012 liu et al.; licensee biomed central ltd.