An all-too common symptom of migraines is feeling nauseous. In fact, in the US eight out of ten migraine sufferers cite nausea as one of their migraines symptoms*, and for children too, nausea and vomiting is an incredibly common migraine symptom.
It’s horrible to experience feeling sick, just as it’s thoroughly unpleasant actually throwing up, but the plus side is that, after vomiting, many migraine sufferers find that their feelings of nausea stop. But why does it?
Scientists don’t know for sure why throwing up stops migraine pain, but there are several theories why it may do so.
A study from 2013 detailed a few reasons why it may do. One of these is that vomiting can induce pain-relieving effects by eliminating sensory input to the gut. Another was that vomiting may lead to unconscious chemical or vascular effects that diminish migraine pain. The final theory in the study was that vomiting may simply be the final stage in the migraine attack, and it’s a natural end to the nausea, headache and other attack symptoms**.
The vagus nerve may also be involved with the end of migraine nausea following throwing up. The vagus nerve is stimulated by vomiting, and stimulation of the vagus nerve is already known to help treat migraine attacks in general. Non-invasive vagus nerve stimulation (the sending of a mild electrical stimulation through the skin to activate the vagus nerve from outside the body) is an option available to some migraine sufferers, and those who suffer with cluster headaches***. Vomiting seems to be one way the body triggers the vagus nerve – thus leading to migraine relief.
Vasoconstriction has also been cited as a reason why vomiting can help to ease the pain and symptoms of a migraine attack. Dilated blood vessels are one potential cause of migraine attacks, at least for some, which goes some way to explain why vomiting, which can cause peripheral blood vessel vasoconstriction, could help to decrease nausea and pain****.