Drinking alcohol warms you up in cold weather.

The image is familiar enough to have become iconic: a Saint Bernard descending a snow-covered Alpine pass, a small wooden barrel hanging from its collar containing brandy for stranded travelers. Whether the real dogs ever carried brandy is disputed, the monks of the Grand St. Bernard Hospice, who bred the dogs from the seventeenth century onward, later maintained that the barrels were an invention of nineteenth-century paintings, but the idea behind the image was not disputed. Alcohol warmed you. Cold was dangerous; warmth was survival; liquor delivered warmth. The logic seemed to follow from direct experience. A shot of whiskey in winter produced an unmistakable sensation of spreading heat.

The sensation is real. Alcohol causes peripheral vasodilation, the blood vessels near the skin's surface widen, increasing blood flow to the skin. The result is a genuine warming of the skin, particularly the face and extremities, which is what the drinker feels. The body interprets this accurately as a local temperature change. What the drinker does not feel is what is happening simultaneously at the core.

The transfer of warm blood from the body's core to the skin surface reduces core temperature. Heat leaves the body through the skin at a rate determined by the surface area exposed and the temperature gradient between the skin and the surrounding air. By forcing more blood to the skin's surface, alcohol accelerates heat loss from the body's center. The core cools faster. The brain, misled by the peripheral warmth, does not register the problem. The shivering response, which normally kicks in when core temperature drops, may also be blunted by alcohol's sedative effects on the central nervous system. The drinker feels warm. The drinker is cold.

Studies on ethanol's thermoregulatory effects, conducted through the 1970s and 1980s, confirmed the mechanism in detail. Research published in pharmacology journals showed that alcohol consistently lowered core body temperature in cold environments even as it elevated skin temperature and suppressed shivering. More recent work confirmed that alcohol lowers the vasoconstriction threshold, the temperature at which the body would normally begin constricting blood vessels to conserve heat, without affecting the shivering threshold, meaning it allows heat to escape before the body's backup warming mechanism engages.

Emergency medicine literature from the same period contains repeated accounts of alcohol-related hypothermia. Cases typically followed the same pattern: a person drinks, feels warm, spends extended time outdoors in cold weather, is found later in a state of hypothermia. In some cases, the person had removed clothing, a phenomenon called paradoxical undressing, associated with late-stage hypothermia, in which the brain's failing thermoregulation produces a sensation of intense warmth just before core temperature drops critically. Alcohol had removed the body's early warning system before the system actually failed.

In actual emergency medicine, administering alcohol to a hypothermic patient is contraindicated precisely because it will further impair the body's ability to restore normal temperature. The rescue image and the medical reality run in opposite directions. The Saint Bernard descends the mountain with a barrel of something that would make the stranded traveler feel better and get worse.

The myth has remained one of the most persistent in popular medicine, partly because the subjective experience of warmth is genuine and immediate, and partly because it emerged from environments, alpine rescue, frontier medicine, maritime tradition, where alcohol was freely available and cold was an immediate threat. The connection made practical sense before physiology intervened. By the time the mechanism was well understood, the idea had been embedded in several centuries of cultural practice. The feeling of warmth, so reliable and so real, proved more durable than the explanation of why that feeling was a signal pointing in the wrong direction.