"icy depths"

This is a piece I wrote, a week or two ago, about a swim that I took. I've been swimming for ten minutes a day in the lake lately, and it has over-all been great. That first swim, though, that was something else:

Almost like a robot, my body felt as I climbed up from the dock, stumbling and halting a bit, wet and in my boxers with the wind blowing over me. I had missed the ladder on the first spin upwards with my legs, grasping with my hands and pulling. I walked up the stairs and into the screened-off room attached to the wooden lakeside sauna. I was slapping at my arms and stomach, half expecting for them to look purple. The lake I had been swimming in was cold, and for the last five minutes a brisk wind was mixing the frigid water up from the bottom where warming light does not penetrate. It was when I started to dry off that the shivering kicked in, and for the next fifty minutes I would not have complete control over my body.
Right before the swim started I was halted on the deck, hesitant to dive into the cold water. I pushed myself to dive in, and from the first cold shock I was having a great time. A lake does not end like a pool. A lake does not feel like a limited experience like a pool does. Sure, it has boundaries. I wasn't swimming in the ocean after all, but I knew I could keep swimming for what felt like forever. When the bottom dropped out from under me, when the lake got deeper, I began to hesitate. I imagined mass murderers and sea monsters rising from the depths. I quavered with a general foreboding reminiscent of how I would feel when above the unknown deepwater of the Mediterranean ocean outside Tel Aviv. But I pushed on, mind over worry, and felt liberated as I glided through the water.
I don't know how to describe it other than silver flowing over my skin. That's how the cold water felt. I could feel each of the muscles in my back, I imagined I could feel the energy released from muscles keeping my body warm. The lake wasn't remarkably clear and I had been told keeping my eyes open would leave them stinging from algae. I could see the mountains rising over the tundra to the south and the rolling hills all around. I was in the tundra in a new way, interacting with it and at its mercy.
"Twenty five minutes?" exclaimed Chad, the camp manager. "Twenty five minutes? You should only swim for about ten if you haven't got a wetsuit. Now you know what it feels like to get close to hypothermic." And I guess I did. It was fifteen minutes after I had stumbled to my tent, grabbed my sleeping bag and crossed off my name from the "out of camp" list in the dining hall, ten minutes into my spastic stay in my sleeping bag shivering, that I remembered to take off my damp pants and my soaking boxers. I don't think I was being illogical when I decided to swim for an extra five minutes; I was having a great time and my body felt great. But walking around with a constant jitter in my jaw, my chest, and each of my limbs, not being able to feel warmth for half an hour, that was impairment.
Luckily I had notified people I was going out swimming and had also made myself known to the scientists doing samples on the lake.
Those last thirty feet to the dock were the hardest. When the momentum of the experience ended and I had to finish the slog was also when the wind kicked in. Scientists call the separation of water according to temperature a thermocline. I could tell you something about a thermocline first hand. My body was heavier, and my calves started to do something that felt like a painless cramp.
I don't regret the swim because it was a great time and because I turned out all right. I learned a bit about caution and plan to keep swimming in the lake for the exercise and for the rush. I'll only be swimming for ten minutes at a time though.
Today I sat at a table that by chance was arrayed with long-distance athletes. Marathon runners, triathlon and Iron-man athletes, and combinations of the two, all devoted recreational runners. I could understand their zeal a little bit, but pushing that hard for a goal that far away and that abstract is a bit strange to me. I’m more used to the short-term rush, although I might be starting to be able to understand that long-term physical and mental drive.