Baby It's Cold Outside

Have you ever tried to pry something open, or twist a bolt, or open a safety pin while in a very cold environment? It hurts way more than you know it should.

If you're reading this blog, odds are very very very good that you have screwed with a safety pin (or 6) while in the middle of a field, with the wind howling and temperatures near freezing. You've done it because you hadn't yet picked up on the trick of using a steering wheel as a mannequin, or because one of your teammates is similarly dependent. Or in the worst case, another racer realizes, with 2 minutes before the start, that his number is on the wrong side, and he needs you to remove and redo all 8 pins.

In the interest of full disclosure, I will confess that I have, in fact, asked people to pin me up. If I have a flappy race number, I'll ask someone to fix it. If I screwed up the number placement so grievously that the officials won't be able to see it, I'll ask someone to fix it. I think that once, I was running so late that I had to ask HardTailJay to pin me, because he is the only person on Earth whose pinning skills I trust.

So today I was helping my labmate Mike disassemble a bookshelf on a loading dock. It was cold, and it was tedious, but I was happy to help out a friend. What struck me, though, is how much my fingers hurt. I would pinch the locknuts (please don't post a comment about my use of the word 'nuts'), and the dull edges would feel like they were slicing my skin.

Probably because I wasn't in full-on pre-race neurotic-freakout mode, I was more aware of this sensation, and more curious about its cause. Why does the cold make the sensation "somewhat sharp" feel like "intense razorsharp pain"

I'll spare you the speculative possibilities I came up with and rejected. The answer is that there is one very specific cell in your skin that responds to "fast pain". It is called "A-delta", and it is sensitive to both mechanical (sharp) and thermal (cold) stimuli. When your fingers are cold, the A-delta cells are brought closer to the threshold (above which they begin to send the "holy crap you're in trouble" signals). When they are subjected to a deep, highly localized pressure (as in when grabbing a locknut [shut up, Jay, Jenks, Aaron, Will, Handloff, and Rob]), they get even closer to that threshold, and occasionally a few will fire those signals up to your brain.

In conclusion, if you're going to be racing, and it's a cold day, you should take care of your own f'ing pins in a warm car. AngryMark and I do so, and well in advance of our starts, because of our freakout-inducing neuroses. Even if you're as cool and collected as a Cap'nChaz, you should take care of your pins as a common courtesy to the people who've already taken care of their own.

References:
Levy, et al. Berne and Levy Principles of Physiology, 4th ed. Philadelphia: Elsevier Mosby, 2006.