Remove the person to a shady or cool place. Give the person plenty of fluids to drink. Force diluted Gatorade or lemonade with one-quarter teaspoon of salt per quart. Spray the person with cool water, or immerse them in water. Treat heat stress promptly at this stage, otherwise the person may develop heat stroke.
Heat stroke is a serious emergency.
Very hot, dry skin temperature. When seen in young, exercising adults, sweating may be present. Rectal body temperature of 104 degrees Fahrenheit or higher. Convulsions or seizures. Spray the person with cool water, and use a fan to cool them.