I lost four pounds during today's walk, in spite of the fact that I drank almost 80 ounces of Gatorade, about 40 ounces of water (plus more when I got home), a Clif Bar, Hammer Gel and Succeed electrolyte caplets. This month's Runner's World has a good article on hydration and an experiment to help you determine your fluid requirements during exercise. So STAY HYDRATED! It's hot out there, people.
