Traditional wisdom among mountaineers is that you should drink water and eat carbohydrates. The thought is that drinking carbohydrates simply slows down the absorption of the fluid and impedes your rehydration. Supposedly, nothing absorbs into your system as quickly as water. A lot of my biking friends, on the other hand, drink all kinds of exotic fluids. (I wouldn’t be surprised if some of them were drinking gasoline). So I turned to the Mayo Clinic web site which, for me, is the gold standard for medical advice. Mayo says that, if you’re training for less than an hour, you should probably just stick to water. If you’re training for more than an hour, however, a “sports drink may be helpful.” Since we’ll be riding 6 to 8 hours every day this summer, a sports drink seems to be called for. Now the question is: which one? Any recommendations?