Hypothermia Series – Part 3: Minimizing Immersion Shock

Okay. You’ve worked on your “inner game.” You’ve identified the value or values that are providing the motivation you need to override all instincts of self-preservation and jump into a cold body of water. Now let’s get to work…

The first area that you will have to manage will be your reaction to a sudden exposure to cold water. Basically, your initial entry into cold water causes a “gasp” reflex followed by a period of hyperventilation and a slight feeling of panic caused by a sudden increase in heart rate and blood pressure. This is an automatic response that you can minimize or eliminate with the right amount of preparation. And trust me on this – you definitely want to avoid this if you can.

I made the mistake once of jumping into an innocent looking swimming hole in northern Arizona only to be rudely reminded that 80F outside temperatures have NO EFFECT WHATSOEVER on icy mountain stream water temperatures.

The immersion shock was so forceful and instantaneous that I literally inhaled a lungful of freezing, mossy water. Don’t let this happen to you!

There are basically two ways to minimize immersion shock:

1) Make sure that you are wearing cold water swim equipment that is appropriate to your own specific physiological needs

2) Take a progressive cold shower prior to your swim

I’ll expand upon the first point in a separate post since it’s a very detailed topic. As far as the second point, though, that’s pretty straightforward:

Progressive cold shower technique:

About 30-45 minutes before your scheduled swim, start out your shower at your regular preferred temperature. After 2 minutes of this, adjust the water temperature downward until it is just slightly below a comfortable level. Stay under this water for another 2 minutes and make sure you expose every part of your body. Keep repeating this process as you adapt to each slight temperature change.

You will soon reach a point were the water temperature becomes uncomfortably cold and you begin to shiver. Force yourself to stay under the water for at least a minute, and focus on exposing every part of your head and your torso to the shower spray.

As you step out of the shower, you will likely be shivering. Dry yourself off and put on some warm clothes. Over the next 15-30 minutes, your body will readjust to this “priming” and your immersion shock will be minimal, if not absent altogether.

This is an excellent technique that I have used time and again with great results. When I did my last swim in San Francisco Bay, I had no immersion shock whatsoever. While a few other swimmers shrieked upon hitting the water and shivered miserably while we were treading water waiting for the start signal, I was able to focus on the swim without any distractions at all. And that’s a much better way to start out your event!

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Mentions Of This Post

  1. [...] In a prior post, I outlined the the “cold shock” response that the human body experiences during a sudden immersion into cold water. To recap, a person who has not properly prepared in advance for a cold water swim will experience a rather “rude awakening” upon entry into the water characterized by rapid, uncontrollable breathing (the “gasp reflex”) as well as an immediate increase in blood pressure and heart rate due to a sudden constriction of the capillaries under the skin. This is not a pleasant experience. [...]

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