Fact: Drinking alcohol actually makes you colder.
Braving the cold night air is always easier after you’ve had a pint or six, but although alcohol makes you feel warmer, your beer jacket it lying to you.
We aren’t quite sure why, but alcohol causes the blood vessels in your skin to relax (or dilate). This directs more blood towards your skin, which tricks your brain into thinking the world around you just got warmer. This is why a glass of wine at Christmas feels like a warm hug, and why certain people can walk home through a snowstorm in Newcastle after 9 trebles.
However, the reason you were feeling cold in the first place was because your body was deliberately directing blood away from your skin to reduce heat loss and keep your core body temperature stable. After having a drink, that blood diverted to your skin will quickly cool off as it comes into contact with cold air, meaning you’ll lose more valuable heat through your skin. Therefore, although alcohol makes you feel warmer, it actually decreases your core body temperature and therefore makes you colder in the long run.
Because of this paradox, beer jackets can save lives: booze can be used to treat frostbite by forcing the body to dilate blood vessels and return blood to dying fingers and toes. A circus stranded in Siberia even saved their elephants by feeding them vodka. However, beer jackets have gotten people into trouble too – every year people wander off drunk feeling rosy and warm, slip or get lost and turn up the next morning frozen solid. So by all means keep your trusty beer jacket, but make sure you have a real one with you too.
‘Another one of Mr Shaunak’s Little Bites of Science’
Image under Creative Commons license