Another controversy related to
BCAA![](http://www.assoc-amazon.com/e/ir?t=abc0764-20&l=btl&camp=213689&creative=392969&o=1&a=B002GJBFA2)
s is whether they improve exercise performance or efficiency. In one experiment, presented at the 2004 conference of the
Strength Training Anatomy-3rd Edition (Sports Anatomy)![](http://www.assoc-amazon.com/e/ir?t=abc0764-20&l=btl&camp=213689&creative=392969&o=1&a=0736092269)
, six healthy men took either BCAAs or a placebo, then engaged in weight training.
When they took BCAAs, their levels of the stress hormone
cortisol![](http://www.assoc-amazon.com/e/ir?t=abc0764-20&l=btl&camp=213689&creative=392969&o=1&a=B0031TRUOG)
and creatine kinase, an enzyme released during muscle breakdown, went down and their testosterone count went up. The authors noted that participants who had more body fat needed a bigger dose of BCAAs to experience any anabolic effect.
Studies show a relationship between the oxidation, or burning, of fat in muscle and the subsequent oxidation of BCAAs in the body.
1 Exercise promotes the activity of an enzyme (BCKDH) that controls BCAA oxidation. That implies that any exercise leading to fat oxidation also raises the requirement for
BCAA![](http://www.assoc-amazon.com/e/ir?t=abc0764-20&l=btl&camp=213689&creative=392969&o=1&a=B002GJBFA2)
intake, explaining why those engaged in endurance exercise, which uses fat as an energy source, need more BCAAs. The same may apply to those engaged in extensive
aerobic![](http://www.assoc-amazon.com/e/ir?t=abc0764-20&l=btl&camp=213689&creative=392969&o=1&a=B0045GT7FO)
exercise to lose body fat.
Taking BCAAs Before Weight Training Can Reduce Levels Of
Cortisol And Creatine Kinase While Boosting Testosterone. http://www.jerrybrainum.com/