The sharp, temporary head pain many people experience after consuming a frozen drink or stepping out into freezing weather is known scientifically as a cold-stimulus headache (CSH). Cold-stimulus headaches are defined by the International Headache Society as a rapid onset of pain resulting from the sudden exposure of the head to a cold stimulus, either internally or externally. The pain typically resolves within a few seconds to minutes once the cold source is removed. There are two distinct triggers for this temporary discomfort: the ingestion of cold food or drinks, commonly called “brain freeze,” and exposure to very low ambient temperatures or cold air. While the triggers are different, the underlying biological mechanism that translates the cold sensation into head pain involves a shared pathway of nerves and blood vessels.
Headaches from Rapid Internal Cooling
The familiar sensation of “brain freeze” occurs when a cold substance, such as ice cream or a frozen beverage, touches the roof of the mouth and the back of the throat. This contact causes a rapid and localized cooling of the blood vessels and tissues in the palate. The medical term for this specific reaction is sphenopalatine ganglioneuralgia.
The sudden drop in temperature is detected by sensory nerves in the mouth and throat. The body responds by rapidly changing the diameter of the blood vessels in the area, first constricting and then quickly dilating them. This fast-paced vascular change in the palate is the immediate cause of the pain signal. The brief, intense headache is a referred pain signal, meaning the brain interprets the signal as coming from a different location than its true source. The pain typically manifests in the forehead or temples, despite the cold trigger being in the mouth.
Headaches from External Cold Exposure
A different type of cold-stimulus headache occurs when the head, face, or neck are exposed to external cold, such as a blast of frigid winter wind or jumping into cold water. This external trigger involves a vascular and nervous system response focused on general heat conservation. The body’s first response to cold air is to conserve heat by narrowing the blood vessels, a process called vasoconstriction, particularly in the skin of the face and scalp.
This vasoconstriction reduces blood flow close to the skin’s surface, helping to maintain core body temperature. The change in blood flow and muscle tension in the head and neck contribute to the resulting headache. When the exposure to cold ceases, the blood vessels may rapidly widen, or vasodilate, which can also generate a pain signal. This type of headache can last longer than brain freeze, sometimes persisting for up to 30 minutes after the cold exposure is removed.
The Neurological and Vascular Pain Pathway
Both internal and external cold-stimulus headaches share a common pathway for transmitting the painful signal to the brain. The main player in this transmission is the Trigeminal Nerve (Cranial Nerve V), which is responsible for sensation in the face, forehead, and the lining of the mouth. This nerve detects the rapid temperature and blood flow changes caused by the cold stimulus.
When the cold triggers a rapid change in blood vessel size, the nerve endings surrounding these vessels are activated. The Trigeminal Nerve then relays this intense signal toward the brainstem. Since the branches of the Trigeminal Nerve cover both the palate and the forehead, the brain misinterprets the origin of the signal.
The sensation of pain is “referred” from the actual site of the cold stimulus, such as the roof of the mouth or the vessels in the scalp, to the forehead and temples. This referred pain is often described as a sharp or throbbing sensation, related to the sudden dilation of the vessels that occurs after the initial cold-induced constriction. For individuals prone to other headache types, such as migraines, this vascular and neurological pathway may be more easily triggered, potentially leading to a more intense experience.
Strategies for Prevention and Relief
The most effective approach to cold-stimulus headaches is to focus on prevention and quick relief. For the internal trigger of “brain freeze,” the primary strategy is to slow down the rate of consumption of cold food and drinks. Allowing cold items to warm slightly on the tongue before swallowing prevents the sudden temperature shock to the palate.
If a brain freeze does occur, relief can be achieved by quickly warming the roof of the mouth. Pressing the tongue firmly against the hard palate for several seconds transfers warmth from the tongue to the chilled area. Similarly, sipping a room-temperature or slightly warm beverage can help normalize the temperature in the mouth and throat.
To prevent headaches from external cold, covering the head and face is the most direct solution. Wearing a hat, scarf, or face mask helps to maintain a warmer microclimate around the face and scalp, reducing the exposure of blood vessels to frigid air. Avoiding rapid transitions between extreme cold and very warm indoor temperatures can also help mitigate the aggressive vascular response that causes the pain.