Smoking
Smoking is a common cause of tension headaches and their underlying symptoms. But, in general, anything that causes stress or strain on the body—physical or emotional—can contribute to the development of tension headaches.
The relationship between smoking and tension headaches is complex. Smoking can trigger migraines in individuals who have migraine disease. For example, this may occur if the person smokes immediately after eating a food that triggers migraine attacks.
Tension and other headaches may also result from smoking-related changes in vascular tone or blood vessel function. For example, smoking reduces nitric oxide levels in the brain and the lining of blood vessels (the endothelium). This may be a factor in causing and maintaining increased muscle tension associated with headaches.
Smoking can also increase levels of carbon monoxide in the brain. Carbon monoxide is thought to cause headaches by causing decreased oxygen delivery to cells; this occurs because carbon monoxide binds to hemoglobin more readily than oxygen does and prevents oxygen from getting released into tissues as needed. Carbon monoxide also inhibits blood vessel function, which contributes to reduced blood flow to the brain (hypoperfusion) and may trigger headache attacks.
