don't forget to hydrate

Last Sunday it was time for me to try the first "longer" 21km (half marathon) of the season. I was building slowly, being careful not to put too much stress on the knees and other joints. After my first 10k run outside, I had some gentle signals being sent by my left knee that it wasn't ready for outdoor running yet.

The run itself went very well. It was also the first time I tried tempo running within a long run (elevated speed for half the run). I was happy with the results of the tempo changes.

Even though it was quite warm out, for some strange reason I only took 1.4 litres of fluid with me. I have read a lot about nutrition, hydration and sodium replacement and I've always been a good follower of all the rules. But on that day I definitely went out short. Half of what I took was Gatorade and I also had two gel packs with me. I did the 21k in 1:51, but in the last half hour I was out of fluid. The weird thing is that the lack of fluid seemed to have an accelerating effect. As I drank the last few sips I still felt good and I thought it would be no big deal. But as I was running the last 5k I was getting thirstier and thirstier. I could still keep my speed up, so the illusion was that I would be okay. But when I got home, I was so depleted I over-hydrated to compensate. I couldn't resist drinking water.

For the next hour or so, I had all kinds of strange feelings. While eating my recovery snack, it was a big effort to chew and digest. Then I was still thirsty, but I didn't want to drink anymore because I felt like lots of fluid was already sloshing around in my stomach. So I laid down and tried to rest to let my system recover. But I had to get up to do something and I was all weak and dizzy - I felt like I was going to pass out. So I sat down and rested some more.

After about an hour and a half, I started feeling well enough to eat and had regained my wits (relatively speaking). I know that it had nothing to do with my BGs, because I had good numbers during the run and recovery time (all between 6 / 108 and 8 / 144).

In retrospect, when I think back on that incident, I'm sort of glad that it happened. I got to really understand what your body goes through with even such a small physiological imbalance. It's one thing to read about under-hydration, but a totally different thing to experience it firsthand. It will definitely make me more vigilant in the future.