One minute you're enjoying your favorite frozen beverage or ice cream cone, and the next minute you're experiencing an excruciating headache which seems to originate from the middle of your skull. This is the dreaded phenomenon known as brain freeze, or ice cream headache. Some experts suggest that up to 1/3 of the population is susceptible to this condition, especially when eating a frozen treat too quickly on a warm day. The pain is similar to that of a migraine headache, but thankfully most attacks last 30 seconds or less.
So what actually causes brain freeze? Researchers suggest it is a combination of your body's overreaction to cold stimuli, freezing of a cluster of nerves above the palate and a sudden influx of warm blood to the brain. Eating all of that ice cream or slushy drink too quickly didn't help matters, either. In fact, it was the initial contact between the cold food and the roof of your mouth which set all of this activity in motion.
When you took an extra large bite of ice cream, some of it reached the roof of your mouth, also known as the hard palate. Behind this hard palate lies a cluster of nerves which act as a protective thermostat of sorts for your brain. The main nerve is called the sphenopalatine nerve, and it's extremely sensitive to abrupt changes in temperature. Once the ice cream or other frozen food causes the sphenopalatine nerve to cool down, it sends out a warning to the other nerves in the cluster. Essentially, your brain has now been told to expect a major freeze, so it had better prepare itself.
Your brain doesn't actually freeze during the episode, but the sphenopalatine nerve cluster didn't know that at the time. The blood vessels surrounding the brain suddenly shrink as a reaction to the cold stimuli, or more precisely overreact. The result for you is a pounding headache which seems to radiate from the sinus area or behind your eyes. The pain is not necessarily triggered by the dilation of the blood vessels, but by the influx of warm blood which forces the vessels open again.
While all of these blood vessels are busy shrinking and reopening with warm blood, the nerves are also contributing to the pain. The pain receptors near the sphenopalatine nerve cluster sense the freezing of the palate, but the pain itself is referred to another area deeper in the skull. This is why you feel brain freeze deep inside your head and not in the roof of your mouth.
One of the quickest ways to reduce the duration of brain freeze is to place your tongue on the roof of your mouth to warm the palate. Once the palate becomes warm again, the nerve clusters are no longer stimulated and they will call off the warning. Drinking sips of warm water will also minimize the effects of brain freeze, as will eating frozen foods slowly and avoiding contact with the roof of your mouth.