To Polar Bear Dip or Not to Polar Bear Dip
Ever wonder what happens to your body during a polar bear dip? So did we
We were curious: what happens to your body during a polar bear dip? Is it safe? Our resident expert Dr. Greg Wells explains.
So you want to bring in the New Year in style do you? Fantastic! That means you’ll be joining other revelers in the traditional New Year’s Polar Bear Dip. Just so that you can fully appreciate the pain and suffering that you’re about to subject yourself to as you bring in the New Year, I thought I’d share some of the physiology that is happening behind the scenes, or under your skin in this case.
The celebrated Polar Bear dip usually involves jumping into a freezing cold body of water, ideally after having chopped a large hole through the ice. As your body hits the water and you become submerged in the icy waters there is an instant shock to the system that feels like pain that comes from every part of your skin that is exposed to the water (note – if you really want to show how tough/crazy you are make sure you submerge your head). The reason for this is that your skin has millions of little nerve endings that sense when damage is happening to the skin. They’re called nocioreceptors. Nocioreceptors are sensitive to mechanical damage, heat and cold. When they’re activated they send urgent signals to the brain saying that “We’re in pain! We are in danger!!!”. That’s why you pull your hand back away quickly when its being burned or you withdraw fast from something that is damaging your skin. Cold causes the exact same reaction. So when you dive in that water – you’re activating pain receptors all over your body. Don’t say I didn’t warn you!
The next thing that happens is that the body tries to protect itself by preserving all the heat that it has inside your blood, organs, muscles and brain. The body tries to preserve its heat by shifting blood flow from the skin and muscles into the internal organs in the chest and belly, which puts tremendous stress on the heart and lungs. The other effect of this shift is that Polar Bear Dippers feel sluggish because of the decreased blood flow to the arms and legs. It will get hard to move. So make sure you have good safety precautions to get you out of the water if your muscles stop working the way you want them to!
Assuming that you get out of the water alive the next thing that will probably happen is that your body will want to heat itself back up as quickly as possible. So you’ll start shivering. Shivering is a survival mechanism that the body uses to protect itself from colder temperatures. Most systems in the body work only within a narrow temperature range. When the body’s temperature drops, the body signals the muscles to start contracting in short, fast bursts—hence, we shiver. These muscle contractions increase energy metabolism in the muscle cell, burn fuel and produce heat. This is the body’s way of surviving in the short term, when its core temperature is too low. If you’re ever out in the cold and find yourself shivering, which means it’s time to go somewhere to get warm, fast.
So now that you know what’s going to happen to you when you jump in that icy water you can really appreciate the event and describe it to your friends and family in more detail. Have fun bringing in the New Year and be safe! Please post your pictures of your polar dip so I can see your adventures @drgregwells on twitter. Happy Holidays and Happy New Year!  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2964977/