(1) Aerobic exercise inhibited oxidative stress and ER stress-induced apoptosis of cardiomyocytes by activating the FGF21/FGFR1/PI3K/AKT pathway in post-MI heart, and fgf21 knockout partially weakened the protective effect of aerobic exercise on the myocardial injury in MI mice. Here, FGF21 is linked to myocardial infarction.