Ppargc1a expression also increases after endurance exercise in mouse (Baar et al., 2002) and human skeletal muscle (Pilegaard et al., 2003; Figure 4) as well as the heart during swimming-induced cardiac hypertrophy (Supplementary Data S8) suggesting that it is a mediator of muscle and heart adaptations to endurance exercise (Holloszy, 1967). This evidence concerns the gene PPARGC1A and cardiac hypertrophy.