Why do people get brain freeze?

Brain freeze, also known as an ice-cream headache, is the result of something extremely cold touching the upper palate of the mouth. When this occurs, a sudden increase in blood flow to the brain occurs, according to Medical News Today.

Scientists at Harvard Medical School speculate that the dilated arteries allowing increased blood flow to the brain and resulting in brain freeze may be a self-defense mechanism to protect the temperature of the brain. Only one-third of people experience brain freeze, notes About.com; however, migraine sufferers are more likely to experience it, according to Medical News Today. The medical term for brain freeze is sphenopalatine ganglioneuralgia.