While multiple intracellular signaling pathways are likely involved in exercise-induced cardiac remodeling, swim training in mice has been shown to primarily induce physiologic cardiac hypertrophy through enhanced insulin growth factor-1 (IGF) and protein kinase B (Akt) – mammalian target of rapamycin (mTOR) signaling (McMullen et al. This evidence concerns the gene IGF1 and cardiac hypertrophy.