Occurrence Characteristics, Possible Mechanism and Subside Reversal of Exercise-induced Myocardial Fibrosis

Long-term exercise induced adaptive remodeling of cardiac structure, electrophysiology and function. The thickening of the heart cavity, thickening of the heart wall, the increase of heart volume, and the improvement of cardiac contractile and contraction function are the main manifestations which is called the "athlete's heart". It is the guarantee of the athletes' high level of competitive ability. However, some athletes are often troubled by heart health problems. In recent years, human and animal studies have found that long-term intensive exercise leads to myocardial damage and even fibrosis, mainly in the atrium and right ventricle, which may be an important reason for the athlete's arrhythmia higher than ordinary people. However, some studies do not support the existence of exercise-induced myocardial fibrosis. In this paper, we reviewed the researches on myocardium fibrosis induced by intensive exercise from human to animal study. And the controversies among the researches are also analyzed. The mechanism of myocardial fibrosis is explained from the aspects of hemodynamics, oxidative stress, hypoxia and inflammation, local angiotensin Ⅱ, TGF-beta 1 and its signaling pathway. The potential methods of eliminating and reversing myocardial fibrosis are also discussed. This paper has certain reference value for preventing and treating exercise-induced myocardial injury, and will further enrich the research theory in the field of exercise heart.