In this study, researchers monitored blood flow in the brain among a group of 13 healthy volunteers while they sipped ice water with the straw pressed against their upper palates -- ideal conditions to bring on a brain freeze -- and while they drank room temperature water.
The people raised their hands once they felt a brain freeze coming on and then raised it again when the pain eased.
The results showed that one particular brain artery called the anterior cerebral artery expanded quickly due to a greater blood flow in conjunction with a brain freeze.
Researchers say the rapid changes in blood flow associated with brain freeze may be part of a natural survival mechanism.
"The brain is one of the relatively important organs in the body, and it needs to be working all the time," says researcher Jorge Serrador of Harvard Medical School in a news release. "It's fairly sensitive to temperature, so vasodilation might be moving warm blood inside tissue to make sure the brain stays warm."
Because the skull is a closed structure, Serrador says, the sudden influx of blood could raise pressure within the skull and cause the pain associated with brain freeze and other types of headaches.
Researchers say studying the changes within the body associated with headaches like migraines is difficult because they can't wait for a migraine to come on in the lab. That means they often miss the physiological changes that occur during crucial period of headache formation.
But brain freeze-induced headaches are easier to predict and resolve quickly, making them better candidates for research.
Their results suggest that rapid changes in blood flow may be responsible for a variety of headaches. Developing drugs that regulate this may provide more effective headache pain relief.
The study was presented this week at the Experimental Biology 2012 conference in San Diego.