How to prevent heat and sunstroke?

Prevention: Keep well hydrated: water/sports drinks/juices; avoid alcohol & caffeinated drinks. Use air conditioning when heat & humidity are high (high heat index); if you don't have it, go to places that do (movie theatres/malls/shopping centers). Check with your doc as to which meds (if any) might predispose you to heat-related illness (due to interference with self-cooling mechanism).

Stay hydrated: Sunstroke occurs when you get dehydrated and run out of sweat, so that your body's thermostat can no longer keep your body cool. Your body relies on water evaporation to stay cool. As long as you drink plenty of water while you're outside, you're not going to get sunstroke. If you suddenly stop sweating, it's time to get in the shade and drink lots of fluids!

Hydration: Adequate hydration, cool clothing, and lots of shade.