Winter Swimming Guide – Chapter 2: Pre-Swim Preparation

Chapter 2: Pre-Swim Preparation – The Real Key to Mastering Cold Water Settings

As noted previously, 80% of the challenge involved with swimming for extended periods of time in the open water involves managing our physiology and our emotions.

And of these two, managing our physiology is the key factor when swimming in the sub-40F zone.

According to Dr. Alan Steinman, former U.S. Coast Guard Surgeon General and rescue physician, there are three phases to our physiological response to cold water immersion:

1) Initial immersion and the cold-shock response (1-4 minutes) – Rapid skin cooling that causes an immediate gasp response, hyperventilation, and the inability to hold a breath. Concurrent responses included peripheral vasoconstriction and increased cardiac output, heart rate, and arterial blood pressure.

2) Short-term immersion and loss of performance (5-30 minutes) – Continued skin cooling causing compromised neuromuscular activity and loss of fine motor control.

3) Long-term immersion and the onset of hypothermia (30 minutes+) – Apathy, amnesia, and loss of consciousness followed by cardiorespiratory failure.

Obviously, we want to stay as far away from phase two and three as we possibly can.

So our goal then becomes twofold – 1) Reduce (or eliminate) immersion shock which unduly stresses our cardiovascular system, and 2) limit the skin cooling which leads to neuromuscular dysfunction.

While proper gear selection is essential for success in this environment, even swimmers with the best gear will falter if they fail to manage their physiology first.  So for the remainder of this post, we’re going to outline some key actions and techniques you can do to further prepare yourself physically for the colder water exposure outside of just selecting your swim gear.

Pre-Swim Preparation


Bottom line, make sure you get adequate sleep the night before you don your thermo gear and leap into the lake. Why, because even mild sleep deprivation can negatively impact your ability to swim in colder water.


Proper hydration involves more than just increasing your intake of water. It also means decreasing your intake of known diuretics such as alcohol and caffeine. Both of these can adversely impact your body’s ability to manage colder temperatures – even if taken the night before. So lay off the booze and double lattes before you swim!


Get quick and easily digestible energy into your muscles as soon as you wake up because they’ll be working extra hard in the colder water. Stay away from most “sports drinks” that are nothing more than non-carbonated soda with the same crappy ingredients (i.e. high fructose corn syrup). My picks – either Cytomax or Hammer Perpetuem.


These are essential to preventing muscle cramping which can take place as you exert yourself much more intensely in the colder water. My current favorite – Trace Minerals ENDURE. I mix this in with my Cytomax, and it makes a huge difference in my performance. I’ve experimented in the past with Hammer Endurolytes, and they also work well. But I prefer the liquid formulation.

Priming (a.k.a. “progressive cold shower technique”)

The idea here is to get your body already physically attuned to exercising in the cold water about 1 hour before you even get in the lake. To minimize the immersion shock, I recommend what I term the progressive cold shower technique.  Here’s how it’s done:

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!

These are tips and techniques we came up with after much trial and error. They are definitely “field tested,” so feel free to try them out to better prepare yourself for an extended cold water immersion.

3 Replies to “Winter Swimming Guide – Chapter 2: Pre-Swim Preparation

  1. i try to “fuel up” with peanut butter and bacon on toast or bagels !and i drink a lot of water just in case i might need to warm up my wet suit …ha ha ha ( no one has ever warmed up their suit )

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