Originally Posted by
Carbonfiberboy
Heat training. Go out in the hottest part of the day, every time. There's a silly thread on BF somewhere about ride early, beat the heat. Heat training is the best training you can do, even for when it's cool. But that's what one does. One has to acclimate to heat, just like acclimating to altitude. That's a good simile. Your body changes. We're very, very adaptable creatures. Drink plenty while you're out, it's not torture, just get your body to practice doing the right thing. And look up "heat shock proteins." You can also sauna 5 days/week and get a similar effect. That's the Finnish secret.
USA's last Junior ITT WC in Dubai spent time training in a closed garage in Phoenix in July and Aug. That middle East heat was rather tame. I used to do rollers in the sauna. Messed up the bike a bit with all the sweat. I really don't think there is any temperature on earth you cannot prepare for. Unprepared, sure - you can die. Masters State (and I think Nats) was near Bakersfield and they were racing at 120ish. The HR goes up, power goes down, but if you have the kit and fluids (and practice) - you are going to be fine (if you are a mature adult male).