So the day before the last post published I almost pulled it. Instead I had a decent case of the screwits and left it alone, because who doesn’t appreciate some self-indulgent public processing from time to time? This week I returned to prepping for my first open water swim this spring. It involves ice water and a bit about circulatory physiology, and it all started with a storm a couple weeks ago…

The weather in the Pacific Northwest has turned, although it is noticeably warmer than I remember for this time of year. We had the remnants of a hurricane blow into our area from across the Pacific (thanks, Ross!) and the low air pressure brought tangible heat and higher tides with it. At one point after the storm blew out I waded into the water at high tide to help my step-dad push a root ball out from behind the house (hard to visualize that sentence, I am sure) and realized that the water did not feel nearly as uncomfortable as I had anticipated. It actually felt… good.

I am not sure if that was due more to the acclimatization work I have been doing (cold showers, immersion into the open water, etc.) or the lower ambient temperature, but it got me thinking. Either way, the temperature of the water shifts by a grand total of about 5F year round. So as long as I am careful about the outside air temperature during exposure there shouldn’t be too much of a problem with increasing my cold water tolerance in Puget Sound, even in the winter months.

Knowing that the typical temperature of Puget Sound is roughly 10C, or 52F, I decided to test something out. Grossly oversimplified (and without links to supporting data, sorry), the veins and capillaries in our extremities close down when exposed to cold in order to preserve our core temperature. But if the extremities get too cold they open back up in order to bring warm blood back into the area and prevent damage. If there is continued cold exposure the cools the blood, the cold blood moves to the core, your internal temperature drops, and given enough time life sucks or ends. Anatomy and physiology lesson courtesy of prior EMS training, Wim Hof video, and observations during the following experiment.

To test this with my own physiology I put water and lots of ice in a large bowl. I let one hand soak in the ice for a while, then switched hands. What I noticed is that you can physically FEEL the response of the circulatory system to intense cold, on a minute level. Jumping into deep 10C water can be an overwhelming experience as your entire body reacts to the drastic change in temperature on the surface of the skin. But thrusting a single hand into ice cold water allows you to directly experience the body’s response.

For instance, my right hand hurt for about 60-70 seconds before I felt the stinging ease and a slight numbness occur. My left hand hurt for about 120-140 seconds. At about the four minute mark my right hand had an easing to the numbness, and a slight warmth infused the hand- the re-opening of the vascular system. I pulled my hand out at that point. By four minutes my left hand was still numb, and not in a ‘whose a tough guy!’ sort of way. So four minutes for each hand, but very different results.

I considered how intensely the body responds to temperature changes, how logical and predictable those responses are, and how unbalanced our physiology can be. I am naturally right handed and seldom engage in activities which require the equal use of both hands or arms, so it makes sense that the vascular system in that hand would be more robust. However I would never have thought it would be so obviously demonstrated or easily observed. To feel such a tangible difference in my body’s reactions in an eight minute experiment was pretty eye opening.

The upshot of this was to decide to try a monthly cycle of immersions into the salt water. It is a constant temperature, easily accessible, and would provide for an easily observable medium to test the effect of exposure on the circulatory capacity of the extremities. In addition I am curious what weekly exposure of the hands to ice water would do to improve or balance the circulatory response of the extremities. If anything interesting occurs I will post it here.