After I flatted on Sunday at the FirmMan 70.3, I decided to start the run anyway, and maybe complete it. Motivation after losing at least 45 mins on the bike was low, but what the heh. I was running ok for the first 6 miles – not great, just ok, but with my limited training it was to be expected. Then things went downhill fast. No energy, crampy, started peeing alot. The few S-caps I had gave temporary reprieve. But it was getting hot and I was fading fast.
I was following my Providence 70.3 strategy of drinking 1-2 cups of sports drink only at each aid station. But clearly it was going right through me and my legs were not feeling good. It was not as if I had consumed more fluid than at Providence – I had consumed less, yet weather conditions were similar. It took two days, but then it dawned on me what happened.
In Providence, I drank about 6-8 oz of Gatorade Endurance at each run aid station. This means I got 150-200mg sodium, 60-90 mg K, and 40-50 calories. Per hour this was about 1200mg Na, 500mg K, and 300 cals. Pretty solid. I often use Endurance in training, and the on-course mix tasted correct.
All that peeing at FirmMan was my body trying to tell me that my blood electrolyte concentration was low and, hence my kidneys were trying to get rid of water to keep the electrolyte balance up. The problem was the Heed they offered on the course, which frequently tasted very watered down. Even at full concentration, 8 oz of Heed only has about 40 mg Na and 16mg K. I suspect that the on-course mix was far more dilute. So I got MAYBE 200 mg of Na in an hour – less than in one S-Cap. It clearly wasn’t enough. I had a few S-caps as backups but not nearly enough in the face of the watery Heed onslaught and increasing temperatures.
So I made the mistake of not preparing for the huge electrolyte differences between Endurance and Heed. If I had, I would’ve brought many S-caps to make up for the lack of electrolytes in the Heed. Now, I know there are some schools of thought that say that electrolyte consumption should be minor – and Hammer is on that train. For me, it simply doesn’t work. I need salt – and lots of it. You may not. In any case, make sure you know what you’ll be getting at every race, and make provisions for diluted mixtures. And if you’re peeing alot, it may not mean that you are over-hydrated – it may mean you are under-electrolyted. In this situation, you are dehydrating even while you drink more. And you could be on your way to hyponatremia.