NRG1 and Myocardial fibrosis: Similarly, moderate aerobic exercise (16 m/min, 60 min/d, 5 days/wk) can activate the neuregulin-1 (NRG1)/epidermal growth factor receptor, ErbB, and fibroblast growth factor 21 (FGF21)/PI3K/AKT to inhibit myocardial apoptosis, reduce the MI area, reduce myocardial fibrosis, and promote cardiac repair and angiogenesis, and improve heart disease’s rational remodeling and cardiac function [6].