Acclimatisation: how cold is too cold?

Wake up this morning to snow in Central London - Yay! I'm so keen to have a swim in the snow at Parliament Hill lido - I've been looking forward to the possibility since hearing the long term weather forecast earlier on in the week. I text Andy (an outdoor swimming friend who also swims at the Cally) to see if he is going and jump into the car with a whole bag full of warm gear and my special thermal shorts and top for afterwards. By the time we get to Parliament Hill the snow has gone, melted by rain, but we're still up for a swim. And it will still be challenging.

There's a board at the entrance to the pool that records the water and air temperature. Last week the water temperature was an exceptionally mild 10C and the air was 12C. This week it's much colder but the good news is that the water is warmer than the air! Ha! We joke and use this as a motivator to get in.

Parliament Hill temperature board announcing the water and air temperature

Andy and I discuss how much we are going to swim - it's a kind of a barter really. Andy says 7 lengths (that's about 420m). Jeez. He's swum yesterday in 7C and so is a bit more prepared for it than me. The coldest water I've been in since around April is probably 9C, so 6C is going to be a bit of an effort.

I decide to do widths rather than lengths - a width is 25m here and a length is 60m so doing a width is psychologically easier to deal with when you are feeling nervous...

I get into the water at the shallow end and wade to the middle of the pool where it is sensible to start my widths. Hmm. It probably isn't that much colder in the water than standing in your swimmers on the freezing poolside.

This past week, with the onset of winter, I've been watching normal people walking down the street all bundled up when the air has really been around 12C or sometimes even warmer. They think it's cold, I muse, but in this age of central heating and proper clothing they probably mostly have not much of an idea of what it really is to be cold - so cold that your nerves are screaming for the pain of the cold to stop.

So what happens at 6C? Well - everyone is different of course but for me it's like this...

Immediately on starting swimmming with my head in the water (no head up swimming for me) I get an ice cream headache which is really horrible. In addition I have to make sure that I swim with my mouth shut, if possible, otherwise my teeth and fillings start to ache. Lips hurt. Nose hurts. Pain and no mistake. I usually swim one width/length and then stop and just wipe my face with my hand, which seems to stop it hurting - I don't know why this works but it is probably just about mentally gathering myself up. Many people get out after this first length/width, which is a shame, as really this is pretty much the worst bit, when your body is still in shock. Once the pain has subsided a few seconds later I set off again to do another width. Still hurting but the intense ice cream headache has subsided. My skin starts to sting now and all my nerves endings seem to jangle. I feel like I've got bad sunburn. My skin feels really hot and oddly burning. But this doesn't hurt so much as it's just - well - a different kind of sensation. I ignore it. Check my core - that always feels warm. After about 2 or 3 minutes I notice that my hands start to hurt, feeling kind of bruised, and then my feet as well. My toes feel sore, like I've stubbed my whole foot, or someone has dropped something heavy on them. I try and relieve it by kicking more, but that's just a lot of effort and hurts too. My muscles contract in the cold and every stroke is an effort - your stroke doesn't have the same range and length as it did before. It feels like someone has come along and tightened up all your muscles so that they are much much shorter and harder to use.

For all that, at this temperature the pain is bearable for 5 to 10 minutes. When it gets to 2C it's much much harder to tolerate the pain. However cold it is, every width or length you are making an assessment of how much longer you can bear the sensations, at the same time as trying to figure out what impact this particular swim will have on your body when you get out. Often I feel fine and able to continue on when swimming, but then am a mess when I am out.

It's sleeting when we are in the water and the sky is a brooding and uninviting grey, which is awesome. There are 6 swimmers in the water. Today I manage 10 widths (so, 250m) in probably about 6 or 7 minutes with all the stopping and wincing and so on, and then get out. Because I haven't swum in 6C for a good few months, I decide to be cautious and get out then. Andy manages another couple of minutes.

I haul myself up the steps and out. Phew. My feet are agony. Well, they hurt but I can't use them. They've gone numb. I have to hobble the 5 metres to where I've left my pool shoes and try to slip them on without touching my toes against the strap which I know will really hurt. Bloody hell. I hobble slowly to the cold concrete changing room. Then is the slow deliberate process of getting dressed. Leave my swimming cap on till last minute before taking off. Actually I can't bear to take it off at all and only do so when we are about to leave the pool. Getting dressed takes a lot of time when your reactions have slowed down in the cold. Everything needs to be considered consciously rather than unconsciously. It must be a bit like watching a drunk person getting dressed, I think.

Many people get the shivers when they've been exposed to the cold and this is the body's natural and excellent response to mild (borderline?) hypothermia - the muscles start shaking in order to generate body heat to warm up the core. However, when the water is this cold, and you're just in it for a matter of a few minutes, that doesn't seem to happen. You don't seem to get so profoundly cold when you're not in so long. All the pain seems to be at the surface, it doesn't penetrate. No shaking/shivering today at any rate. Andy and I pile into my car, bundled up like Eskimos, and crank up the heaters. The car immediately steams up impossibly like it's filled by so many damp dogs. Home for hot drinks and a hot water bottle. My feet still hurt five hours later, and I feel totally sleepy. I wouldn't miss it for the world.

Comments

[Erika]

Hi Sally

This being my first winter I read this post with interest. I'm still bearing the 7 degrees - your post has inspired me not to take a break! Well done for getting in this morning.

Erika

[Hi Sally]

You is like well mad Sally.

You have inspired me to stay at home in an electric blanket.For the rest of the entire winter.

Your misplaced friend

Paul

[Scarlett]

Good for people to know.