Why Does Ice Cream Give You Brain Freeze?

It arrives without warning, usually at the best part of a hot afternoon. You take a big, happy bite of ice cream or a long pull on a frozen slushy, and a moment later a sharp, stabbing ache lands right in the middle of your forehead. You squeeze your eyes shut. You press a hand to your head. You make a noise that sounds like a kettle. And then, almost as quickly as it came, it is gone, leaving you slightly shaken and holding a dessert you now regard with suspicion.

The experience has a lot of names. Most people call it brain freeze. Doctors also call it an ice cream headache or a cold stimulus headache, and it has an impressively long scientific name: sphenopalatine ganglioneuralgia. It is not serious, and it does not actually freeze anything. According to the Cleveland Clinic, the pain usually lasts only a few seconds and rarely more than a couple of minutes.

It happens when something very cold hits the roof of your mouth or the back of your throat suddenly. That area is full of sensitive nerves and small blood vessels. The body notices a sharp drop in temperature and reacts as if it needs to protect itself, tightening some blood vessels and then letting blood rush in to warm the area back up. That quick change in the size of the blood vessels, right next to all those nerves, is what seems to trigger the pain.

The strangest part is where you feel it. The cold is in your mouth, yet the ache appears in your forehead or behind your eyes. The nerves in the roof of the mouth are connected to nerves that also serve the face and head, which is probably why the brain reports the pain from the wrong place. Which raises a delightful question: why would a body built to survive winters get so upset about a scoop of mint choc chip?

A study published in 2012 went looking for the answer. Researchers at Harvard Medical School asked thirteen healthy adults to sip ice-cold water through a straw, aimed so that it hit the roof of the mouth, while a special ultrasound test tracked the blood flow inside their heads. When brain freeze struck, blood flow through a large artery at the front of the brain, the anterior cerebral artery, rose dramatically and suddenly. As the artery narrowed again, the pain faded.

The researchers suggested this might be a protective reflex. The brain is very sensitive to temperature, so a rush of warm blood could help keep it at a steady temperature, but the extra blood arriving so quickly may briefly raise pressure inside the skull and cause pain. They hoped that understanding it could eventually help with other kinds of headache too. Some research has found that people who get migraines are more likely to get brain freeze as well.

The good news is that the cure is simple. Stop eating the cold thing for a moment, and warm the roof of your mouth, either by pressing your tongue or your thumb against it or by sipping something at room temperature. Better still, eat very cold things slowly. Children seem to get brain freeze more often, perhaps because they have not yet learned that ice cream will wait.