I get a lot of junk mail, mostly catalogs for home stores, but every once in a while I open something I can actually use. Case in point: A pamphlet on hydration from the American Road Race Medical Society (ARRMS) showed up at my apartment recently. Just in time to help me figure out my drinking strategy for the Boston Marathon! (I also got a discount coupon for a final resting place from a funeral home—let's hope I don't need that one any time soon.)
To figure out how much water you should be sipping, you need to calculate how much you lose from sweating. ARRMS recommends weighing yourself naked, going for a one-hour session in the conditions and at the pace you expect to race, and then stripping down, toweling off, and stepping on the scale again. The difference in ounces is the amount of water you should be consuming DURING a run. For example, if you've lost 12 ounces, you should be guzzling 4 ounces of water every 20 minutes. Drink too little and you risk dehydration, too much and you could end up flooding your body.
I don't have a scale at home, so I haven't been able to crunch my numbers yet, but I'm planning to hit a gym soon. I carry a water bottle with me on runs longer than an hour, and typically take a swig when I'm thirsty, so this might change how I approach hydration on race day.
Do you drink during workouts?