Up until we embarked on this drawn out process of swimming daily for a year (a daft dare that got out of control), I would probably have said that I’m someone who feels the cold. Having said that, in cold weather I usually pile on hats, scarves, a vest and woolly jumpers etc so in actual fact don’t generally feel the cold. Instead I experience that mid life, menopausal, ‘over sweat’ brought about from wearing too many layers. But I am now wondering whether in fact I don’t feel the cold so much after all. Am I in fact a mutant?

“It’s not that bad” I say after a short while in the water.

Karen is still panting. Much squealing.

“No really, it’s actually quite nice” I reassure.

Still panting but with quieting whimpers.

I start our daily nattering whilst Karen breathes loudly and half listens. I imagine that she’s probably missed the first five minutes of every conversation we’ve had since last November due to her concentrating on breathing through the cold. But ever the caring friend, she’s not mentioned it.

There is much written about how cold water swimming improves mental health, cardiac health, and a better immune system, but I’m now beginning to feel a bit guilty that I evidently don’t feel the cold as much as Karen. The daily ritual of immersion has been challenging over the winter but I feel it’s been bearable. My swim buddy may not agree. I’m sure some will say that Karen’s system is still pining for the temperatures of her upbringing in Hong Kong and that my childhood swimming off Calshot was a better grounding for adult sea swimming, but it may be deeper than these experiences. It might be that I have mutant genes.

Apparently, 1 in 5 of us has mutant genes (reassuring that I’m not a total mutant to be honest). A fifth of the world’s population lack a muscle protein called alpha-actinin-3 (ACTN3) due to a single genetic change. Muscles have fast-twitch muscle fibres (strong and explosive) and slow-twitch muscle fibres (more energy efficient and good for endurance) which control how we use them effectively. In a nut shell, ACTN3 deficiency is not good if you want to be a fast sprinter, but not having it benefits your endurance performance (although we are really talking elite athletes here to be fair). This also shows itself in temperature control – “If you’re alpha-actinin-3 deficient, then your body can maintain a higher core temperature and you shiver less when exposed to cold, compared with those who have alpha-actinin-3” (The Conversation)

Ok – enough babble. What I think this means is that if I do in fact have the mutated gene (like 1.5 billion other people worldwide) then I will be able to swim further and more steadily than Karen who, with the regular gene, should be able to plough ahead of me more quickly. It would also mean that a) I feel the cold less than my swim buddy; b) I’ve been unnecessarily hard on Karen telling her that it’s not ‘that’ cold and she needs to woman up; and c) there is a recognition that we both need to swim much further to properly test any of this out instead of pottering along chatting and giggling each day.

The good news now is that the water is finally warming up a little. It’s nudging double figures for the first time this year and there’s lots of sunshine to bring a smile.

“I think I’m going to miss the cold water you know when it really starts to warm up” I casually say.

I’m not sure if Karen’s heard me or she’s pretending not to have… but she does seem to be muttering something rude under her breath.