# What causes brain freeze?

> Nothing in your head freezes. The cold stays in your mouth, and the pain shows up somewhere else.

https://learnfold.app/wait-how/how-brain-freeze-works/ · Updated 2026-10-30

Brain freeze is a short, sharp headache set off when something cold passes over the roof of your mouth or the back of your throat. The cold stimulates nerves there, including branches of the trigeminal nerve, and is accompanied by fast changes in blood flow inside the head. You feel it in your forehead or temples rather than in your mouth, and it usually fades within seconds.

That's the agreed part. How exactly a cold palate becomes a forehead headache is still being worked out, and the studies don't all point the same way.

## What doctors officially call it

Brain freeze has a formal entry in the International Classification of Headache Disorders, published by the International Headache Society. It is listed as "headache attributed to ingestion or inhalation of a cold stimulus," and described as short-lasting frontal or temporal pain, which may be intense, set off in susceptible people by cold material passing over the palate or the back wall of the throat. The cold can be solid, liquid or gas, so a lungful of icy air counts.

The diagnostic criteria are specific. The headache comes on immediately after the cold stimulus and resolves within 10 minutes of the cold being removed. It is usually on both sides of the head. The classification notes that rapidly swallowing crushed ice slurry is especially likely to set it off, but that eating ice cream even slowly can do it.

## How common is it?

Very, though the numbers depend on who is asked and how. A 2019 survey of 618 adults by researchers in Halle, Germany, found that 51.3% had experienced it, with no difference between men and women. Among those, 92.7% said it lasted under 30 seconds. A 2016 study at a German school found that 62% of students aged 10 to 14 reported it, against 36% of the women and 22% of the men among their parents and teachers. It also ran in families. Students whose mother had it had 10.7 times the odds, and 8.4 times if their father did.

A 2023 systematic review summed up the wider literature as giving lifetime prevalence of 15% to 37% in the general population and roughly 40% to 79% in children. Some of that spread comes from asking people to remember a pain that lasts half a minute.

## Your brain doesn't get cold

Nothing in your head freezes. The trigger is cold on the palate and throat, and the pain is felt somewhere else. It is a bit like a smoke alarm in the kitchen that sounds in the hallway. The signal starts in one place and gets reported in another.

The 2023 review notes that the palate is supplied by the trigeminal nerve, a major sensory nerve of the face, while the throat and esophagus are supplied by the glossopharyngeal and vagus nerves. The authors suggest that which of these nerves gets activated may explain why brain freeze doesn't always feel the same.

## What's happening in the blood vessels?

There are two main ideas, according to the review, and they probably overlap. One is that cold receptors in the mouth fire directly and set off a nerve reflex. The other is that local and brain blood vessels rapidly constrict and dilate, activating pain sensors in the vessel walls.

The blood flow studies don't agree with each other.

- **The famous study.** In 2012, Jorge Serrador and colleagues at NUI Galway and Harvard Medical School had 13 healthy volunteers sip iced water through a straw pressed against the palate. According to the university's news release, the anterior cerebral artery dilated rapidly as the headache began and then constricted as the pain faded. The team suggested the extra blood might help keep the brain warm, and that the sudden inflow could raise pressure inside the skull. This was a conference presentation with a small sample, and the release mentions no peer-reviewed paper.
- **A different artery, the same direction.** A 2019 study by Hensel and colleagues measured the middle cerebral arteries while people drank 200 ml of ice water. Everyone showed falling vascular resistance and rising flow velocity, and those who got a headache showed more. Flow rose further in people whose eyes watered. The authors read this as a sign of a trigeminal nerve reflex that widens blood vessels.
- **The opposite direction.** The 2023 review also describes an earlier study that measured middle cerebral artery flow while adults ate ice cream and found a decrease in flow velocity in those who developed a headache, with no change in those who didn't. That drop was put down to vessels narrowing.

So blood vessels are involved, the trigeminal nerve is involved, and watering eyes during an attack point to a reflex involving the trigeminal nerve and the autonomic nervous system, as a 2016 study by Mages and colleagues noted. Whether the key event is widening, narrowing or one after the other is not settled.

Play the sketch, then switch explanations. The highlighted routes show ideas under study, not a settled chain of causes.

## Is there more than one kind?

Possibly. A 1992 study at the City of London Migraine Clinic applied ice cream to the palate of migraine patients and student volunteers, or had them swallow some. The typical headache started after about 12.5 seconds on average and lasted about 21 seconds. But a significant minority had a different one that started much later, around 102 seconds, and lasted around 236 seconds, especially after swallowing.

The 2016 Mages study compared ice cubes pressed to the palate with fast gulps of ice water in 77 volunteers. Ice water triggered brain freeze far more often, 39 people versus 9, with a median onset of 15 seconds against 68. The pain was mostly described as stabbing after ice water and pressing after ice cubes, and 10 of the 39 people had a second attack. The authors took that as support for the idea that two types exist. A 2019 review concluded that how bad it gets, how often and how fast seem to depend on the speed of the cold and the size of the area it touches.

## Is brain freeze linked to migraine?

The classification says it is common, "especially among those with" migraine. The research is less tidy than that. A 2004 experiment found head pain in 74% of migraine patients exposed to cold versus 32% of people with tension-type headache. The 1992 London study found the opposite pattern, with ice cream headache less common among migraine patients than among student volunteers. The 2019 German survey found people with migraine had no higher risk of getting brain freeze, though those with migraine or tension-type headache rated the pain as more intense. The studies used different groups and methods, which may be part of why they disagree.

## Does eating slowly actually help?

There is one randomized trial. Its first author, Maya Kaczorowski, was listed at a middle school in Hamilton, Ontario. In the 2002 BMJ study, 145 students were each given 100 ml of ice cream and told to eat it either in under 5 seconds or over more than 30 seconds. Twenty of the 73 fast eaters (27%) reported brain freeze, compared with 9 of the 72 slow eaters (13%). Most of the headaches, 59%, were over in under 10 seconds. The authors flagged their own weaknesses, no blinding and self-reported results.

Popular tips such as pressing your tongue to the roof of your mouth get repeated a lot, but none of the studies reviewed here tested them.

## Pain that turns up in the wrong place

The obvious next question is why pain from the roof of your mouth gets felt in your forehead at all, and from there it is a short step to why cold drinks make some teeth ache. Learnfold will plan a course on either, wait for your OK, and then add a linked page for each question you follow, so a [curiosity rabbit hole](/use-cases/follow-your-curiosity-rabbit-hole/) stays in one place. Its lessons are AI-written and anything about the body deserves a second look, so here is [how to check an AI explanation for mistakes](/guides/check-ai-explanations-for-mistakes/). For another question about the senses, try [what bees see that you can't](/wait-how/what-bees-see/).

## Quick answers

**What causes brain freeze?**

Cold food, drink or air passing over the roof of the mouth or the back of the throat. That cold stimulates nerves there, including branches of the trigeminal nerve, and is accompanied by fast changes in blood flow in the head.

**How long does brain freeze last?**

Usually seconds. In a 2019 survey of 618 adults in Germany, 92.7% of people who got it said it lasted under 30 seconds, and the international headache classification says it resolves within 10 minutes of the cold being removed.

**Why does brain freeze hurt in your forehead?**

The cold acts on the palate and throat, but the pain is typically felt in the forehead or temples, usually on both sides. Researchers link this to the nerves involved, though the exact pathway is not settled.

**Does eating ice cream slowly prevent brain freeze?**

It seems to lower the odds. In a small 2002 BMJ trial, 27% of students told to eat ice cream in under 5 seconds got brain freeze, compared with 13% of those told to take more than 30 seconds.

**Is brain freeze linked to migraine?**

The evidence conflicts. Some studies found it more common in people with migraine, one found it less common, and a 2019 survey found no higher risk but more intense pain in people with other headache types.

## Sources

1. [4.5.2 Headache attributed to ingestion or inhalation of a cold stimulus](https://ichd-3.org/other-primary-headache-disorders/4-5-cold-stimulus-headache/4-5-2-headache-attributed-to-ingestion-or-inhalation-of-a-cold-stimulus/), International Classification of Headache Disorders, 3rd edition (International Headache Society)
2. [Cold-Stimulus Headache in Children and Adolescents](https://pmc.ncbi.nlm.nih.gov/articles/PMC10144624/), Life (Bonemazzi et al., 2023, systematic review)
3. [Cold Stimulus Headache](https://pubmed.ncbi.nlm.nih.gov/31172287/), Current Neurology and Neuroscience Reports (Chebini and Dilli, 2019, review), via PubMed
4. [Prevalence and characteristics of headache attributed to ingestion or inhalation of a cold stimulus (HICS)](https://pubmed.ncbi.nlm.nih.gov/31645112/), Cephalalgia (Kraya et al., 2019), via PubMed
5. [Increased Blood Flow Velocity in Middle Cerebral Artery and Headache Upon Ingestion of Ice Water](https://pubmed.ncbi.nlm.nih.gov/31316454/), Frontiers in Neurology (Hensel et al., 2019), via PubMed
6. [Experimental provocation of 'ice-cream headache' by ice cubes and ice water](https://pubmed.ncbi.nlm.nih.gov/27206961/), Cephalalgia (Mages et al., 2016), via PubMed
7. [Ice cream headache in students and family history of headache](https://pubmed.ncbi.nlm.nih.gov/27039390/), Journal of Neurology (Zierz et al., 2016), via PubMed
8. [Ice cream headache, site, duration, and relationship to migraine](https://pubmed.ncbi.nlm.nih.gov/1555929/), Headache (Bird, MacGregor and Wilkinson, 1992), via PubMed
9. [Prevalence and clinical characteristics of an experimental model of 'ice-cream headache' in migraine and episodic tension-type headache patients](https://pubmed.ncbi.nlm.nih.gov/15030539/), Cephalalgia (Selekler, Erdogan and Budak, 2004), via PubMed
10. [Ice cream evoked headaches (ICE-H) study: randomised trial of accelerated versus cautious ice cream eating regimen](https://pmc.ncbi.nlm.nih.gov/articles/PMC139031/), BMJ (Kaczorowski and Kaczorowski, 2002)
11. [Brain Freeze Find Might Help Solve Migraine Mysteries](https://www.universityofgalway.ie/about-us/news-and-events/news-archive/2012/april2012/brain-freeze-find-might-help-solve-migraine-mysteries-1.html), University of Galway news release (2012)