How Swimming in Cold Water Effects Muscles

After reading about how so many OW swimmers swim without wetsuits I decided that I needed to toughen up.  Mau took me to his 20C ocean water pool for my first cold water pool training.  Our objective was to do 1-3k; it was really mentally hard as I was constantly looking at my watch and the laps were not increasing fast enough. The first 1k felt ok, but during the 2k the coldness had entered my body; my toes were numb and I couldn’t feel my hands. I was swimming fast because I wanted to get out. After 2k, I decided I needed to warm up and went to the indoor pool. What happened here was very weird; I got into the indoor pool and I had no strength. The water temp was probably 26C so it was significantly warmer than the outdoor pool but it still wasn’t as warm as the pools I usually swim in.  When I started swimming I could not dig down with each stroke and find power. Usually when I am tired, I can find power within tired muscles but I couldn’t feel anything. My arms felt empty. I was also doing 24-25 strokes a lap which is much higher than my average.  I extended the length of my strokes and slowed down my turnover but I couldn’t decrease stroke count. It was completely un-gratifying.  I am convinced that I need to do more cold-water training so my muscles get used to these adverse effects.

The rest of the day I was in a state of exhaustion and in total we had only done 3k. What happened to cause such unfavorable effects on my muscles? I searched Google for “How swimming in cold water effects muscles” but got mostly hypothermia explanations and the water temp was not cold enough be qualify for hypothermia. Mauricio has a theory and I will post it here. But I would love any medical professionals or anyone who might have an idea to chime in.

“What I think is happening is that because of the drastic temperature change, our bodies are led to believe that we are swimming in much warmer water than what it actually is.  Our bodies perceive changes in temperature very dramatically when the temperature changes SUDDENLY, and that is what happened today.  So, our bodies adjust as if the water was hot.  So, what do our bodies do if the water is hot (remember, our bodies thought that the water was much hotter than what it actually was)?  They immediately try to cool the system down. The body’s biggest concern is the brain and internal organs, so warm blood flows away from our core to our extremities and skin in order to cool our body (since the body thinks that the water we are swimming in is hotter than our blood’s temperature), leading to less blood in our muscles, muscle relaxation and less oxygen in our muscles –> Less energy.  That’s my bet. “

Penny McDermid -our first World Reader donation

A big THANK YOU to Penny McDermid who was the first to click on the donate button and support our cause (Education Africa via As a thank you we would like to offer you a seat on the boat that will accompany us across the Strait.