Often they occur in the late afternoon or evening, as a result of accumulated stress during the day. Chronic tension headaches may occur every day, or almost every day, for months or years. They may last from several hours to all day. But tension headaches may also be triggered by physical causes such as arthritis, poor posture or staying in one position for long periods of time. If chronic tension headaches occur everyday or almost everyday, it is important that you consult a doctor immediately.
Migraines produce moderate to severe pounding or throbbing pain, commonly on one side of the head.
An aura is a type of visual disturbance which causes sufferers to see flashing spots, colors, lines or shapes in their field of vision - or temporarily to have only partial vision. Migraines vary widely in duration, from a few hours to 3 days. Auras typically last about a half hour and then subside before the pain begins. Migraines may occur only occasionally or several times a week. The average is 1-3 attacks per month.