Sweat Rate

I think I've finally figured out a reasonable strategy for fluid and electrolyte replacement!

Lately I've been anal retentive about documenting my pre and post run weight, fluid intake, electrolyte intake, etc. As it turns out, I've only been drinking about half of what I should be, which can be a BIG contributor to muscle cramping. I've been somewhat reluctant to gulp down lots of fluids because: a) fear of hyponatremia, especially being a salty sweater, b) I don't want an upset/sloshing stomach while running, c) I never needed that much fluid during road runs, d) most of the peer reviewed literature suggests that it's best to be a little dehydrated than overhydrated, and e) I don't want to be pissing like a race horse during a trail run.

Last weekend at Afton, I calculated my sweat rate to be 2.25 lbs/hour, meaning I need to drink 36 oz of fluid/hour to maintain my body weight (I only drank 32 oz for the 2 hours I was out there - less than half of what I should have). I also took 1 S cap/hour and didn't have any problems with cramping or hand swelling.

Today at Hyland, my sweat rate was 2.1 lbs/hour, meaning I need to drink 33-34 oz fluid to maintain (I drank 16 oz/hr + 1 S cap). Pretty close to what I'd expect compared to Afton, especially since Hyland is easier terrain to run on.

Game plan for Saturday at Afton = 36 oz HEED/hour + 1 S cap/hour, which works out to about 400 mg Na/hour (recommended range is 200-500 mg Na/hr) and 21 mg K/hour (recommended range is 20-50 mg K/hr).

If I cramp up this time, it will most likely be because of muscle fatigue due to deconditioning rather than dehydration or electrolyte imbalance. And the cramping will most likely take place in the grass that is taller than I am on the snowshoe loop. I hope I don't get lost.... ;)