The International Headache Society's "Classification of Headache Disorders," defines an exertional headache as severe, sudden onset head pain that occurs during or immediately after vigorous physical exertion. The classification system distinguishes primary exertional headache, which has no identifiable structural cause, from headaches resulting from other disorders that just happen to first appear during exercise. Since some of these disorders can be dangerous, patients who experience any severe head pain for the first time should seek medical attention immediately in order to rule them out.
Primary Exertional Headache
Exertional headaches are uncommon, so there are no systematic studies of primary exertional headache. Most information on primary exertional headache, also known as benign exertional headache, comes from cases reports of patients seeking emergency room or consulting neurologist attention. One such article, published in the January 2003 issue of the "Annals of Emergency Medicine," describes four emergency room patients who were eventually diagnosed with primary exertional headache. All of these patients were men who experienced the sudden onset of severe headache while engaging in some form of weight lifting. All describe a "popping" or "bursting" pain on both sides of the head that lasted from 2 to 24 hours. This case report is consistent with others that have found primary exertional headaches more common in people over 40 and four times more common in men then in women. The pain is usually on both sides of the head and can last anywhere from a few seconds to two days. Most patients diagnosed with primary exertional headache can reduce or eliminate future headaches by following simple preventive measures, such as warming up properly and refraining from breath-holding while weightlifting.
An intercranial hemorrhage occurs when a blood vessel within the brain bursts. The symptoms of an intercranial hemorrhage depend upon the location of the vessel in the brain. Subarachnoid hemorrhages, which occur near the outer lining of the brain, usually cause sudden, severe headache with a stiff neck, but no other symptoms. Intraparenchymal hemorrhages occur deeper within the brain and usually cause sudden-onset weakness, numbness or other sensory defects, although occasionally headache is the only symptom. In a case report of 28 patients referred to a neurologist for severe headache brought on by exertion, published in the March 1996 issue of "Neurology," 10 were eventually found to have subarachnoid hemorrhages. Since an untreated subarachnoid hemorrhage can cause loss of consciousness and death, it is vital to rule it out as a cause of a sudden and severe headache before arriving at a primary exertional headache diagnosis.
Migraine Triggered by Exertion
Migraine headaches can be triggered by exertion, and sometimes they are mistaken for primary exertional headaches. Since treatment for a migraine is significantly different from treatment for a primary exertional headache, this mistake can lead to needless suffering. Fortunately, migraines have several features that help to distinguish between the two types of headaches. Migraines usually build up over the course of an hour or two, so that patients often know when a headache is coming on, while exertional headaches have sudden onset. In addition, migraines are sometimes preceded by an aura, usually involving visual disturbances. Migraines frequently cause increased sensitivity to light, while this is rarely a symptom of exertional headaches. Migraines are usually felt on only one side of the head, while exertional headaches are usually on both sides. Finally, sleep usually improves a migraine but has little effect on an exertional headache.