At the December Dip (7th December), I did 2 widths of Parliament Hill lido (28m per width) and the water was either 5°C or 6°C depending on who you ask. The following weekend (15th December) I did 2 widths of Tooting Bec lido (30m per width), and the temperature was down to 4°C.
On 19th December, I met up with my friend at Tooting Bec. I think the temperature was still about 4°C: we did 3 widths, then went in the sauna, then did another 4 widths, then sauna again, then a final dip (straight in and straight out at the shallow end) where we submerged without wearing swim caps. I found that it was much easier to get into the water the 2nd/3rd time, either because I was used to the temperature or because I'd warmed up in the sauna. In the past, I've not been keen on saunas: I felt dizzy when I came out. However, that wasn't a problem here at all.
On Wednesday (Christmas Day), I went back to Tooting Bec again, and the signing on sheet said that it was still 4°C. This time I did 4 widths, then sat in the sauna, then went in briefly at the deep end without my swimming caps, and that all went well.
Today, the signing in sheet said that it was 4°C. However, over on Twitter someone said that it was 3°C, and it definitely felt colder than Wednesday. Still, it was perfect weather: clear blue sky, with the sun shining and reflecting off the water, so the pool looked very inviting.
I did 4 widths, then went into the sauna. There are 3 levels of seating inside, and the top is the hottest. I started out at the bottom, but when I moved up to the top it felt hotter than it did on Wednesday (when I was also at the top). After I got out, I felt a bit nauseous, although I wasn't in any imminent danger of vomiting. I went to the shallow end and did another "in and out" dip without my swimming caps, and I felt better after that: certainly more alert. I then walked along the row of cubicles looking for mine. They all have brightly coloured doors, and I knew that my door was red, but it wasn't the first one I looked at.
Then I woke up. I could feel the dream slipping away as I regained consciousness, but I remembered being at the lido. I then noticed that there were people standing around and shouting at me, and that the back of my head hurt. It turned out that I'd keeled over on my way to my cubicle, so I was lying flat on my back on the concrete and I'd hit my head. I have to say, full marks to the lifeguard: I can't have been "out" for long, and he was on the spot immediately, along with a couple of club members. They helped me get up and back to my cubicle, and lent me a jacket to wrap around me for the short distance, then the lifeguard waited outside until I'd got dressed.
I then sat down in the café for a bit, while the others got me a hot drink. The lifeguard took a look at my head: it was bleeding a bit, but he didn't think that I needed an ambulance. (Fortunately, I seem to have a fairly thick skull.) His theory is that shifting between the extreme temperatures dropped my blood pressure, and that's why I fell over. I think that I was in the water for about 10 minutes, then the sauna for another 10 minutes, then back in the water for about 10 seconds. I've swum in colder water than that before; in particular, the OSS December Dip was down to 0.1°C in 2010. However, I just did 2 widths there, rather than 4. So, I think I need to be careful about my limits and not overdo it. I also noticed that the paddling pool at the lido was mostly frozen over today; I don't quite understand the physics of it, but apparently shallow water freezes faster (at the surface) than deeper water.
I cycled up to the lido today, but I've left my bike there for now, and a couple of other swimmers kindly gave me a lift home in their car. The lifeguard said that I should be fine to swim again tomorrow, so I'll just take it easy for the rest of the day: crank up the central heating, pile on the layers (I'm currently wearing my Robie Robe over my cycling gear), have some hot food/drink, and slump in front of the TV.
So, this is all a bit embarrassing, but no major harm done. Hopefully this blog post is coherent (rather than resembling the output of a drunken monkey mashing a typewriter) which means that my brain is still intact. At least exceeding my limits gives me an idea of what they are, so I can work with that.