Improved Exercise Tolerance Through Supplement of Keto Acids in not Well-trained Subjects

Abstract

Exercise tolerance can be determined by different factors, in which an accumulation of ammonium resulting from protein degradation during exercise may be one of the mechanisms responsible for a limited exercise capacity. Keto acids are biochemical analogues to amino acids and may serve as ammonium shuttle (a-keto-glutarate, AKG) or ammonium catcher (branched chain keto acid, BCKA), so that ammonium can be synthesized into urea or recycled through trans-amination into amino acids. Through lowered ammonium accumulation exercise tolerance can be improved. PURPOSE: To study effects of keto acid supplement (KAS) on exercise tolerance in not well-trained subjects. METHODS: 36 not well-trained subjects (26±6 yr, 180±6 cm, 78±9 kg) were divided through a double-blinded randomization into the Placebo-(no KAS), AKG- and BCKA-group, respectively. KAS (0.2 g/kg/d) was given over a 4-week Training followed by 1-week regeneration. In the placebo-group the subjects got fructose instead of KAS in equal amount of energy as KAS. The subjects underwent a training program (5 units/w with 30 min endurance running (ER) followed by 3 x 3min speed running (SR)). The training time each week, maximal power output on cycle-ergometry (Pmax) and isometric strength of m. quadriceps femoralis (Fmax) before, after training (TR) as well as after 1w-regeration (RG) were recorded. Results (mean±SD):TABLECONCLUSION: Under KAS the not well-trained subjects could do much more training than those without KAS and reach higher power output on ergometry as well as higher muscle strength. Therefore, the supplement of keto acids could lead to significant improvement in exercise tolerance in not well-trained subjects.