The possible reasons for hematuria after strenuous exercise are as follows: First, chronic diseases such as nephritis, urinary tract infections or urinary tract stones are present before exercise. The local mucosal damage is aggravated by strenuous exercise, which can lead to increased bleeding, and therefore a state of hematuria in the naked eye can occur. In this case, there are certain signs and symptoms before exercise, chronic lumbar pain or the presence of urinary frequency and urgency, and a series of tests such as routine urinalysis, ultrasound examination of the urinary system and quantitative measurement of urine protein are needed to confirm the diagnosis; secondly, the organism itself does not suffer from any disease, but strenuous exercise causes violent shock to the kidneys and contusion occurs, resulting in bleeding. The common sports are boxing or wrestling, etc. Excessive strenuous exercise leads to local contusions and mucosal bleeding, so the symptoms of hematuria may appear. In this case, the hematuria can disappear on its own after stopping the exercise, and routine urinary system examination does not reveal the presence of stones, tumors or infections.