Headaches that have an explosive onset with exercise, including sexual activity, generally are benign in origin. A subarachnoid hemorrhage, a mass lesion in the brain, or an anomaly of the posterior fossa must be considered, however. The mechanisms that produce sexually induced or cough headaches of abrupt onset are unknown. It is known, however, that a rapid increase in intrathoracic pressure suddenly reduces right atrial pressure and presumably decreases venous sinus drainage from the brain. This situation results in a transient increase in intracranial pressure. Jaw pain that occurs with chewing often is considered to be TMJ dysfunction when arthritic in quality and if subluxations of the jaw can be shown on the physical examination. Giant cell arteritis and common or external carotid artery occlusive disease should be considered when the pain is ischemic in quality. An anginal equivalent is another possibility. Headaches that worsen with vigorous exercise are commonly migrainous. When their onset is apoplectic with exertion (particularly exertion against a closed glottis), the most likely diagnoses are increased intracranial pressure, a posterior fossa abnormality, or benign exertional headaches. Most cardiac induced headaches, but not all, are of a more gradual onset. If there are significant risk factors for coronary artery disease, an exercise stress test is appropriate. A therapeutic trial of nitroglycerin may help to establish a diagnosis if it improves the headache. Using antimigraine drugs as a diagnostic test is inappropriate because triptans and ergots are contraindicated in the presence of coronary artery disease, and a positive response is not diagnostic of migraine.