Yesterday I went out for about 30 miles with some moderate climbing involved. This is a route I ride often. The temperature was in the mid 90s and the humidity up in the high 80s to low 90s. Typically, this kind of weather is not a problem for me. I hydrate adequately before, during and after the ride. I use a sports drink on the ride and take along an energy bar (which I seldom have to use). In the past, the ride has never been a problem even in identical weather. At about the 22 mile mark, after a brief quarter mile climb on a 9% grade, I simply hit the wall. I stopped and while eating the energy bar in the shade was wondering why today felt so hard. After a five to seven minute rest I climbed back on the bike and only got about four miles before I knew I had officially "bonked". The last four miles were torture. After limping home, cooling off and resting for an hour it came to me: I had skipped my usual bowl of oatmeal, raisins, and honey that morning for two "breakfast bars." I sure won't do that again. Who would have thought that oatmeal can make such a difference?