[header] How to stop a severe headache after a long run [title] Recognize the symptoms. [step] Primary exercise headaches are the most common type of exercise headache. It is not known why some people experience primary exercise headaches, although some doctors believe it may have something to do with dilated blood vessels caused by strenuous activity. 
Common symptoms of primary exercise headaches include : [substeps] A throbbing pain in one or both sides of the head. Headaches that begin during or immediately after strenuous activity.