I'm in an area of Florida where the heat index gets close to 110 and the humidity is insane for 9 months of the year. You learn to drink water way before start time and keep drinking water after you punch out in those months. During the insane heat times, I couldn't care about numbers or production, I'll usually drink water at each stop whether with a bottle in the cab, or a huge hug with ice in the back.
Know your limits, cold towels and cold water on your arteries points will cool down fast. I alternate water and Gatorade. Also a very cold can of low sodium V-8 will replenish all the stuff you're sweating out. My wife hates the summers because I go through so many shirts in a day.
I don't care if a supervisor is yelling or screaming at me about useless metrics, in the heat my safety and health come first. I recognize when I've gone too far and I'll stop in some AC and catch myself. Any union steward worth his weight in gold when have a field day with management if they got on a driver for hydrating or cooling down in the heat. It's in UPS's own safety methods. They love contradicting themselves but a good steward usually points that out.
