It is common for a severe headache, particularly a migraine, to lessen or even disappear after vomiting. This phenomenon, while providing temporary relief, stems from complex physiological interactions. Understanding these mechanisms offers insight into why this occurs.
The Migraine Connection
While vomiting can accompany various types of headaches, it is most frequently linked with migraines. Migraines are a neurological condition characterized by intense throbbing pain, often on one side of the head, that can significantly disrupt daily activities. Beyond the headache itself, migraines frequently present with other symptoms, including nausea, vomiting, heightened sensitivity to light (photophobia), and increased sensitivity to sound (phonophobia).
The same neurological pathways initiating migraine pain can also activate the brain’s vomiting center. This connection, often called the gut-brain axis, plays a role in generating nausea and vomiting during a migraine. Nausea affects over 90% of migraine sufferers, with vomiting occurring in about 70%. This makes vomiting a common symptom and a primary context for observed relief.
How Vomiting Provides Relief
The temporary relief experienced after vomiting during a headache, especially a migraine, involves several proposed physiological mechanisms. These actions can collectively contribute to alleviating the intense discomfort.
One significant factor is the stimulation of the vagus nerve. This nerve serves as a communication pathway between the brain and various organs, including those in the digestive system. The act of vomiting intensely activates the vagus nerve, which can then influence pain pathways in the brain. This vagal stimulation may release neurochemicals that possess pain-relieving properties, such as endorphins. Non-invasive vagus nerve stimulation devices are now approved for treating migraines, highlighting this nerve’s role in pain modulation.
Another theory involves a “neurotransmitter reset.” Migraines involve changes in neurotransmitters like serotonin and dopamine, which regulate pain, mood, and sensory perception. Vomiting might temporarily alter the levels or balance of these chemicals. This shift could lead to a momentary reduction in pain signaling, providing relief.
While not a direct pressure reduction in most typical cases, the intense physical exertion of vomiting can cause transient changes in blood flow dynamics within the head. Some theories suggest this intense muscle activity could temporarily constrict blood vessels, which might reduce localized inflammation or pressure contributing to the headache. This effect, however, is considered less central than the vagal or neurotransmitter theories for the typical headache.
The body’s natural painkiller system, involving endorphins, also contributes to relief. Intense physiological events like vomiting can trigger the release of these endogenous opioids. Endorphins bind to pain receptors in the brain, reducing pain perception and providing temporary relief.
The autonomic nervous system, which controls involuntary bodily functions, is also involved in migraines. During a migraine, an imbalance can occur in its sympathetic (“fight-or-flight”) and parasympathetic (“rest-and-digest”) branches. Vomiting is a strong parasympathetic response, and this shift in autonomic balance might help calm the nervous system, impacting pain perception and easing migraine symptoms.
When to Be Concerned
While vomiting might offer temporary relief for certain headaches, particularly migraines, it is not a healthy or recommended strategy for managing headache pain. Relying on vomiting for relief can lead to dehydration and other complications.
Seek immediate professional attention if a headache with vomiting indicates a more serious underlying medical condition. This includes a sudden, severe “thunderclap” headache, or one accompanied by new neurological symptoms like weakness, vision changes, confusion, difficulty speaking, or a stiff neck.
Headaches developing after a head injury or trauma, or those that progressively worsen, also require prompt medical attention. Rather than seeking relief through vomiting, individuals with persistent, severe, or unusual headaches should consult a healthcare professional. A medical diagnosis can help determine the cause and establish an appropriate treatment plan.