Cold water shutdown

November 14, 2018

Everyone deals with swimming in cold temperatures differently, so it seems. It depends on a number of factors, one of which is the amount of body fat a person has. Being on the leaner side my body tends to shut down when the water temperatures are low. For me this firstly results in my fingers and toes going numb, then my arms and legs feeling heavy and then to the point where I just can’t swim anymore and have to make my way back to shore as best I can. For me this can happen in the middle of the summer in lake Wanaka, where I do the majority of my open water swimming.

The lake varies in temperature during the summer from around 12 degrees up to 20 degrees during a really warm period. The lakes temperature is dictated by a number of factors such as rainfall (not just direct but also in the headwaters), snow melt, wind stirring the water up, sunshine hours and of course air temperatures. All of this means that one week I can happily swim in the lake for an hour or more without feeling cold and the next week I can struggle to be in there for 20 minutes.

For me the ‘cold water shut down’ that I get means the following:

All of the above means that often I will avoid lake swims on colder days. Until now I have been swimming and racing in a top of the line Blueseventy Helix, often with a neoprene vest underneath. The Helix has been great in terms of freedom of movement and part of me was concerned about changing suits and having restricted movement.

When I decided to commit to helping others overcome my fear of water it occurred to me that I will be spending more time in the water than usual and potentially using less energy and therefore getting colder than ever. I had heard about the Blueseventy Thermal Reaction suit and so contacted Dan from Blueseventy to ask if I could trial one. He very kindly sent me my very own Thermal Reaction, a Thermal Skull Cap, Thermal Socks, Thermal Gloves, goggles and swim caps! You can read about these items and their properties at

I received these items mid-winter and so my first use of the suit was in the pool. I wanted to see how my arms and shoulders felt with regards to movement and to see if they fatigued due to less flexibility in the suit. I was really pleased with the flexibility of the suit and didn’t feel anymore restricted in it than I do wearing my Helix. I was also interested to see what the effect of the added thickness to the leg area would make. Due to my body’s composition and also my swim technique (or lack of in areas) my legs and hips tend to be ‘sinky’. The added thickness in these areas on the suit is a definite benefit to me. Overall the true test of the gear came at the start of this week when I entered the lake for the first time this season.

The weather has been mixed in Wanaka over the past two weeks with fresh snow on the mountains, high winds, rain interspersed with warmer days that created snow melt that then enters the lake and rivers that feed the lake. The water temperature of the lake was around 12 degrees and I had been warned by other lake swimmers not to go in as even the seasoned lake swimmers that swim all year round were suffering from the cold. I had also just arrived back from Xterra World Champs in Hawaii where the temperature was around 35 degrees so anything was going to feel cold to me. Anyway, I decided that this was a great time to try the Thermal Reaction and the thermal accessories.

After donning my wetsuit, thermal socks, gloves, swim cap, thermal skull cap and googles I entered the water. The first thing I noticed was that it didn’t feel cold. It wasn’t until I was deep enough that some water entered the suit through the zipper that I felt the cold. I splashed my face with the breathtakingly cold water and then swam for a short distance. An ice-cream headache formed instantly but other than that I was fine. The Thermal Socks were absolutely brilliant. I hardly noticed that I had them on from a swimming point of view and my feet were warm. The wetsuit was also doing a great job of keeping me warm and my movement in the water were not at all restricted by the suit. The Thermal Skull Cap was typical in that they aren’t the most comfortable as they are held on by a strap under the chin which is always going to feel somewhat uncomfortable. From a heating point of view however this was also excellent. I just wished that it could have covered the spot just above my goggles where the ice cream head ache had formed! The skull cap also inhibits your hearing more than a regular silicone cap however this is not too much of an issue. The Thermal Gloves whilst definitely doing a great job of keeping my hands from going numb were somewhat cumbersome to swim with. The feel of the water is so important whilst swimming that I think that this is always going to be a hard piece of equipment to perfect but at least I was in the water!

I have now had two short lake swims (20mins or so each) and both times I have got out of the water without any numbness or without feeling at all cold! For me this is massive, and I am so excited at the prospect of more comfortable and productive swims.

In conclusion my initial views on each product are as follows: