Endurance Exercise Training and L-Carnitine Supplementation Stimulates Gene Expression in the Blood and Muscle Cells in Young Athletes and Middle Aged Subjects

Endurance exercise training is known to increase fatty acid (FA) oxidation during exercise and to stimulate mRNA synthesis of mitochondrial carnitine acyltransferases in skeletal muscle. To test the hypothesis that long-term endurance training induces cellular adaptions in different tissues, we determined the relative mRNA abundances of these genes in skeletal muscle and in blood cells from young athletes and middle aged untrained persons. The first trial examined 6 cross-country skiers, at the start of high volume/low intensity exercise training and 6 months later, when training at the same exercise intensity had elicited a significantly slower rate of lactate accumulation. In the second trial of 24 middle aged untrained (12 placebo and 12 carnitine supplemented) probands the mRNA expression was determined at the beginning and after three months of a low intensity endurance training program.