Curious Kids: what is brain freeze?

Curious Kids is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

What is brain freeze? – Question from the students of Ms Young’s Grade 5/6 class, Baden Powell College, Victoria.

Australia had one one of its hottest summers on record this year (thanks, climate change, thanks a lot). Many of us probably gobbled up an ice cream and perhaps too quickly.

After doing this, you may have been unlucky enough to get an intense squeezing or stabbing sensation on your forehead, your temples or the back of your head. This is brain freeze, also known as an “ice cream headache”.

“So” you say, feeling smart, “brain freeze is just a kind of headache! I already know all about those”.

You are, of course, correct. But brain freeze is a bit weird. While it’s true that you do put ice-cream inside your head to eat it (your mouth is technically part of your head), you don’t typically put it into the parts of your head that hurt when you experience brain freeze. To put ice-cream into your forehead or temples would be a very weird surgical procedure that I do not advise you to try at home or anywhere else. It’s also hard to imagine a situation in which it would be medically necessary so it seems unlikely that it would be available on Medicare.

So why do your forehead and temples (or even the back of your head) hurt when you put ice cream in your mouth too fast?

There are several different ideas as to why, but the answer definitely has something to do with what happens when we cool down the roof of our mouth.

When you cool down the roof of your mouth, the coldness is picked up by nerve cells that live there and whose job it is to detect cold. This information about coldness is sent to your brain via a nerve. When the roof of your mouth is very cold, these cells (and so this nerve) will be very active.

Now, this nerve also contains information from other cells, including the ones that detect cold and painful stimuli from other parts of your head, including your very face.

It may be (we’re honestly not sure) that when the cells that sense cold in the roof of your mouth are very active, this somehow also activates the bits of the brain that are usually activated by the face cells. As a result, the cold fools your brain into thinking that your forehead hurts.

Another possibility is that, as delicious icy treats quickly cool down our tongues and mouths, it actually cools the blood in blood vessels that supply blood to your head. These blood vessels respond by changing how much blood flows into your brain. Only a few scientists have actually tried to measure this, and those that have don’t even agree about whether there is more or less blood going into your head. Everyone, however, agrees that it hurts.

It may be some combination of these two things: that activation of nerves causes a change in how much blood is going into your head. It might even be both things together!

Why don’t we know how brain freeze works?

Here’s the thing about science: “what is brain freeze” is a fantastic question for a curious scientist to ask, but to get the answer, scientists need to convince other people (politicians, other scientists and members of the public) that they should be given the time and money to answer that question.

Unfortunately, the availability of time and money are not as boundless as the curiosity of scientists.

The result of all this is that sometimes, simple and beautiful questions like “what is brain freeze?” don’t get as much attention as other questions that might seem more pressing.

Instead, these beautiful questions fall away, like a scoop of ice cream loosened by an enthusiastic but careless scientist who may not have the time or resources to investigate brain freeze in the lab, but excitedly discusses it with a friend over an ice cream anyway. My advice? Stay curious. Eat ice cream. Slowly.

Read more: Curious Kids: If Australia is at the bottom of the world, why are we the right way up?

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au