Hydration and electrolytes

I find it hard to dial in the right amount of electrolytes when training. The first time I became aware that there was a problem was in the '07 Mooseman Olympic when I was beginning to experience cramping in my calves and quads by the end of the bike leg and after finishing the run, my hamstrings got into the act also so that for an hour or so my legs were trying to cramp in both directions at once -- not good.

Until then I'd been hydrating with alternating bottles of Cytomax™ and water, which gave me about all the carbohydrate I could absorb, I'd experience some issues with cramps in training but written it off to muscle fatigue. After the painful post-mooseman experience I started adding more electrolytes to the mix and found that my problems with cramping had passed.

This fall I had a routine physical and checked in with my doctor about my tendency to experience passing out when I stand up during periods when I'm training hardest. I've always written it off to my relatively low blood pressure and heart rate. The doc suspected insufficient hydration / blood volume but we ruled that out because I routinely check my weight after training to ensure that I'm hydrating well enough. What she suggested is that I'm down on electrolytes. Since then I've further upped the amount of salt I take in when training and I think I can say that this is addressing the problem ... a happy thing as needing to be frequently cautious about the simple act of standing up gets tiresome.

How to manage hydration requirements

The first thing is to measure your sweat rate, this will vary depending on exertion levels and the weather conditions you're training in, so do check in a variety of circumstances. It's a simple thing, just get on the scale before you head out and then again when you're done.
([start weight]+[water intake]-[finish weight])/[time training] = sweat rate.
I lose something north of 3lbs per hour of water when going hard in high temperatures, given that, it probably shouldn't have taken me so long to figure out that while I was hydrating fine, I was losing more salt than I was replacing.

live and learn :-)