I have religiously worn a helmet since 1977 when I donned a "leather hairnet" because the USCF required it. However, my recent forays on the south Louisiana roads in 100F+ heat index have resulted in me pouring water through the vent holes and shifting my helmet to obtain (albeit only momentary) relief from having my brain literally baked. At this point I'm wondering what is the greater risk: heat stroke or the possibility of a head injury? Where I live, one is more probable than the other (guess which one).