Does climbing in the cold (Like New England winter sport-climbing) cause you to increase capillary circulation to your hands? During my first few climbing sessions last winter my fingers felt as if they would freeze off. But later that winter, the same temps and cold rock didn’t feel that bad. If there is a peripheral vascular adaptation to the cold, would this pay off in spring as you are increasingly able to perfuse crimping muscles and remove metabolic waste? Just imagine the headlines: Freeze your fingers today, send tomorrow!
—Pat Bagley / Rock and Ice forum
Geez, Pat, you know how to throw a curly ball.
When subject to cold temperatures, your body tries to conserve heat by superficial vasoconstriction. The result is in an increase in peripheral resistance
that forces blood to evacuate from your forearms through fewer vessels. Outcome: Coke-bottle pump.
The palms have a capillary bed that is even more important for thermoregulation. When these constrict due to cold, and you squeeze the blood out of your
finger tips, your fingers go numb by virtue of reduced blood perfusion, and the small muscles in the hand (largely used for fine motor control, though
they do contribute to finger power) become cold and oxygen starved, i.e, you will feel like a stroke victim trying to knit.
Over a short period, winter, there are not likely to be marked increases in vascularization, but rather an increased tolerance to lactic acid in conjunction
with reduced resistance from deeper capillary beds and venous capacity.
You probably adjust your behavior to accommodate cold without even realizing it. Thermal wear, long-sleeved thin tops, etc., all help to increase and maintain
internal temperature. This in turn reduces peripheral resistance.
I dare say you approach routes differently as well, selecting ones that are less finger-intensive early on, or at least have a shake out jug not far into
the route, on which you can allow your forearms some time to recalibrate and get some blood moving through.
Freezing for fitness purposes seems a little arduous. Try putting a constriction bandage around your forearm instead, as essentially that would achieve
the same result and is not conditions dependent.
This article was published in Rock and Ice No. 219 (July 2014).