The physiology of cold hands and the physics of silent nights

Up until a few weeks ago, all I could do was reminisce to my grandsons about the quality and quantity of snow we used to have “back in the olden days” when I was a boy. This is shaping up to be the longest stretch of pre-Christmas snow we’ve had in the five short years I’ve been a grandpa, and the boys and I are working to make the most of it.

There’s a special magic about the snow that can lead a kid to learn to handle freezing temperatures in a way a thousand days of barren frozen ground could never teach. If you’re having fun, you don’t much think about being cold. The key, of course, is to retreat from the cold before the fun is entirely over. For most kids, that’s a lesson that can only be taught the hard way.

Back in the days of my youth, the lesson of staying out too long was renewed with each first snowfall of the year. Our neighborhood sledding hill was a good half-mile trudge across unshoveled sidewalks, across a frozen pond, through a tall, dark woods, across a pasture field, then up to the top of the slope.

After all the work of slogging there while pulling our steel-runner sleds behind, the last thing we were apt to do was quit early so we could walk home while still warm. The signal for us to head for home was either “frozen” hands, “frozen” feet or both. The quotation marks emphasize the fact that while we may have felt our digits had been reduced to skin-covered icicles, the truth was our bodies were enacting a self-preservation plan.

The first stage of that plan is a constriction of blood vessels in our extremities to drive more blood to our body’s core, where our vital organs reside and our surface to volume ratio is lowest — a strategy that limits heat loss. In the most extreme of circumstances, our bodies are willing to sacrifice those extremities to stay alive. That “frozen” sensation comes compliments of your nervous system telling your brain in no uncertain terms that it’s time to get inside and get warm.

Once inside, the dull numbness is not-so-gradually replaced by a painful burning sensation. That’s our nervous system again encouraging our brain to tell us to do the right thing and slowly, carefully warm ourselves. That burning sensation comes compliments of the quickening dilation of blood vessels and the rush of warm blood into once-narrowed veins. The last thing one should be inclined to do is stick “burning” hands too close to a fire or under scalding water. (Pretty cool how the brain uses pain to keep us from actually hurting ourselves, huh?)

If all goes well, fingers and toes will soon lose their sting and regain their color in a matter of minutes. The once “frozen” sufferer is left with a good lesson on getting out of the cold before the cold gets them.

If you have comments on this column or questions about the natural world, write The Rail Trail Naturalist, P.O. Box 170, Fredericksburg, OH 44627, or email jlorson@alonovus.com. You also can follow along on Instagram @railtrailnaturalist.