I was thinking a little about the heat today when I went riding (It has been a hotter than usual summer in the extreme southwest end of Virginia, where I live, also). BTW there is a recent thread on BF called something like "How do you beat the heat" with some good comments. This year I had my closest encounter with being overcome by the heat while mowing my yard a couple of months ago. I was doing the wrong things, not drinking water or taking breaks (I thought, hey, it's only going to take an hour). After mowing for about 45 minutes I could feel my heart racing like I had been running and I actually got chilled. I did eventually get inside and did recover. Now if it is 95+ degrees with high humidity I will time myself (around 20 minutes) and "force" myself to take a break.

Same on the bike, I've observed my bad riding habits in the heat (like trying to power my way up hills and getting that similar heart-racing delirious feeling). Now I try to listen to my body and take it relatively slower in the heat and look for opportunities to take breaks (and I try to take them BEFORE I actually need them). I'm not "training" for anything so I haven't had to make great adjustments. I think we as cyclist think that (because we are "out there" doing something while many adults are couch potatoes) that we have superhuman ability to take the heat. I'm 45 and I find myself feeling that way still (at twenty I thought I was immortal). We need to put aside our egos, learn to listen to our bodies, and accept that the human body (like any machine) will fail under certain circumstances.