How a Migraine Happens

Theories about migraine pain

Older theories about migraines suggested that symptoms were possibly due to changes in blood flow to the brain. Now many headache researchers realize that changes in blood flow and blood vessels don't start the pain but may add to it.

Current thinking regarding migraine pain has moved more toward the source of the problem, as improved technology and research have paved the way for a better understanding. Today it is widely understood that chemical compounds and hormones, such as serotonin and estrogen, often play a role in pain sensitivity for migraine sufferers. More recently, proteins made by nerve cells (neuropeptides) have been shown to be involved in the pathway that leads to a migraine.

One aspect of migraine pain theory explains that migraine pain happens due to waves of activity by groups of excitable brain cells. These trigger chemicals, such as serotonin, to narrow blood vessels. Serotonin is a chemical that's needed for nerve cells to communicate. It can cause narrowing of blood vessels all over the body.

When serotonin or estrogen levels change, the result for some is a migraine. Serotonin levels may affect both men and women. Changing estrogen levels affect women only.

For women, estrogen levels naturally vary over their lifetime. There are increases during the childbearing years and decreases afterwards. Women of childbearing age also have monthly changes in estrogen levels. Migraines in women are often linked to these fluctuating hormone levels. They may explain why women are more likely to have migraines than men.

Some research suggests that when estrogen levels rise and then fall, contractions in blood vessels may be set off. This leads to throbbing pain. Other data suggest that lower estrogen levels make facial and scalp nerves more sensitive to pain. Experts are still studying exactly how neuropeptides, serotonin, and hormones interact to cause migraines.

What commonly triggers a migraine?

People who get migraines may be able to identify triggers that seem to kick off the symptoms. Some possible triggers include:

• Stress and other emotions

• Biological and environmental conditions, such as hormonal shifts or exposure to light or smells

• Severe tiredness (fatigue) and changes in sleep patterns 

• Glaring or flickering lights

• Weather changes

• Certain foods and drinks

The American Headache Society suggests writing down your triggers in a headache diary. Take this information with you when you visit your healthcare provider helps them to find headache management strategies.