This somehow sums it up:
Now, if you were out for some fun on the seashore on a hot summer day and someone nearby suddenly fainted, would you know what to do? The dude could be suffering from heat stroke (also known as "sunstroke") and you're standing there clueless as to how to help him!
Here are some guidelines if you should happen to give first aid to a person suffering from heat stroke:
While waiting for the paramedics to arrive, initiate first aid. Move the person to an air-conditioned environment -- or at least a cool, shady area -- and remove any unnecessary clothing.
Try these cooling strategies:
- Fan air over the patient while wetting his or her skin with water from a sponge or garden hose.
- Apply ice packs to the patient's armpits, groin, neck, and back. Because these areas are rich with blood vessels close to the skin, cooling them may reduce body temperature.
- Immerse the patient in a shower or tub of cool water, or an ice bath.
Read more about heat stroke symptoms, treatment and prevention here