Nosebleeds after running may be related to the external environment, abnormal nasal mucosal secretion function and blood pressure fluctuations during exercise. When the external environment is dry, frequent breathing can aggravate the dryness of the surface of the nasal mucosa, coupled with the decline in their own nasal mucosal secretion function, can continue to aggravate the symptoms of nasal dryness, which leads to an increase in the brittleness of the capillaries of the nasal mucosa, which is more likely to rupture and bleed. There will be some fluctuations in blood pressure when running, especially when suffering from hypertension and other underlying diseases. Strenuous exercise can cause the blood in the nasal mucosal capillaries to increase the impact force on the wall, which can easily lead to blood vessel rupture and bleeding. For patients with nosebleeds, it is routinely recommended to improve the blood routine, coagulation function and other tests, and it is necessary to first investigate whether there is any blood system disease caused by the disease, so as not to delay the condition. If you have a nosebleed after running, you should consult a doctor in time to be on the alert for blood system diseases without delay to avoid delaying your condition. Pay attention to rest on weekdays, moderate exercise, drink more water, and reasonably match the diet.