[Grape Ape]

Eat before you get hungry, stay well hydrated, and replace lost electrolytes.

Hophead has it dead on eat before you get hungry and drink before you are thirsty. If you are hungry or thirsty it is to late and it is harder to catch up in the heat.

Another thing is don't try to act like a super hero, there is nothing wrong with calling it done and heading back early. Better to take care of yourself than to get injured.