How can exercise effect migraines?

Exercise & migraines: Vigorous exercise may trigger migraines due to sudden increase in oxygen demand, drop in blood sugar &/or dehydration from poor intake before exercise, sore muscles from strenuous exercise done infrequently, head injury. Studies have shown, however, that moderate exercise can reduce the number & severity of attacks & regular exercise may prevent migraines.

Better or worse: Whole body exercise that raises the pulse could actually relieve a headache as increased blood circulation carries away muscle toxins. But exercise that mainly involves muscles in pain or spasm could make things worse. Depends.