Prolonged swimming can cause thickening of the interventricular septum. This is a benign thickening and is generally not a cause for concern. The normal thickness of the ventricular septum is 6~12mm, more than this range belongs to the thickening of the ventricular septum, and the common causes are physiological causes and pathological causes. 1. Physiological septal thickening: this situation is mostly seen in athletes, long-term participation in physical labor, such as long-term swimming, these are benign septal thickening, generally not serious thickening, no symptoms, do not have to worry about, and do not have to deal with. 2. Pathological ventricular septal thickening: Clinical causes of ventricular septal thickening include hypertension, hypertrophic cardiomyopathy, dilated cardiomyopathy and so on, ventricular septal thickening due to long-term myocardial damage, and patients with myocarditis, myocardial inflammatory changes caused by viral or bacterial infections, which leads to ventricular septal thickening. These conditions require active control of the primary disease to avoid exacerbation. The doctor should determine whether the thickening of the interventricular septum is physiologic or pathologic according to the patient’s specific condition. For some pathologic causes of ventricular septal thickening, it is necessary to control the primary disease, such as controlling blood pressure, reducing cardiac load, etc., through the doctor’s guidance on the use of medication, but for swimming or exercise-induced ventricular septal thickening, do not need to be dealt with.