Sudden death occurs during strenuous exercise, there are the following precursors: 1, patients appear dizziness, blackness in front of the eyes, headache or repeated unexplained syncope, if this occurs, the patient may die suddenly at any time; 2, some patients have arrhythmia, panic, palpitations, tachycardia, manifested as heavy sweating, pale, these are early warning signs of sudden death, at this time should be actively related to the examination These are early warning signs of sudden death and should be actively monitored to avoid sudden death. Some patients may ignore the above warning signs, and if they continue to exercise, it may trigger cardiac arrest at any time, leading to sudden death.