Brain Freeze or ice cream headache are terms used to describe a form of cranial pain or headache which human beings are known to sometimes experience after consuming cold beverages or foods such as ice cream, often as a result of rapid consumption. The reaction is triggered by the cold substance consumed coming into contact with the roof of the mouth while the individual eats it. It triggers nerves that give the brain the impression of a very cold environment . To return warmth to the brain, blood vessels start to swell, which causes the pain for, typically, around 30 seconds .