Why does alcohol warm you in the summer but increase the risk of freezing in winter?

Dear Cecil:

I can understand that drinking alcoholic beverages in the summer can make you feel hotter, but I also read that drinking in the winter also makes you colder. How can this be? And what is alcohol's effect on your body in temperate weather?

Cecil replies:

Drinking makes you feel warmer no matter what the season, but its net effect is to cool off the body. Alcohol is what is known as a vasodilator–it causes the blood vessels to expand, particularly the capillaries located just under the surface of the skin. In doing so it overrides the body’s normal heat regulating process, which also makes use of dilation. What happens when the blood vessels expand is that a greater volume of blood is brought to the skin surface, where the heat of the blood is dissipated to the surrounding air. That’s why you take on a flushed appearance when you drink. Since most of your heat-sensing nerves are also located in the skin surface, drinking makes you feel superficially warmer in both summer and winter. In winter, however, heat is carried away so rapidly that the body’s metabolic reserves are quickly exhausted, resulting in frostbite or hypothermia. Hence the danger of freezing to death after a midwinter binge.

Send questions to Cecil via cecil@straightdope.com.

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