Our academy does not use AC. To be honest, I am not a fan of breathing fake air when working out. It is so hot most days that I sweat just sitting on the mats listening to instruction. Most days it is an endurance test just to drill. I like to believe that it makes us tougher having to persist under harsh conditions. I know that for me it makes me push myself even harder.
The most important thing to remember is to properly hydrate at all times or it can create some big problems. I am not very good at this. I have to remind myself to drink water on a regular basis. When I don't hydrate properly it causes me to have dizzy spells, blurred vision and muscle cramping.
Prior to this heat wave, when I was training for the Worlds, I was out running Town Lake. I was almost home when I just stopped sweating. This is the worst thing that can happen to you. I felt like I was about to faint. I got goose bumps and started to feel nauseated. Thankfully I was almost home and I was able to immediately slam some water. It was almost too late. I felt awful and ended up having to lie down for a few hours. I was completely useless for the rest of the day.
So bottoms up. And remember to drink your suggested gallon a day of water.