The reason for coughing up blood after strenuous exercise may be the rupture of capillaries in the lungs, underlying lung diseases. Strenuous exercise, the respiratory rate will be accelerated, breathing will deepen, easily lead to bronchospasm, irritating cough, coughing violently will lead to capillary rupture of the surface of the respiratory tract, there will be coughing up blood, this general coughing up blood is not a lot of, can be recovered on their own. There are basic lung diseases such as tuberculosis, pneumonia, lung malignant tumors, etc., itself will have coughing up blood, coughing up blood after strenuous exercise, this is the need to actively improve the chest radiographs, tuberculosis mycobacteria culture, pathology biopsy, etc. to clarify the diagnosis, and then carry out symptomatic treatment. Coughing up blood after strenuous exercise should promptly consult the hospital to clarify the cause.