Don't use them when you are alone. Do not drink alcohol or beverages with caffeine because they speed up fluid loss. Check which ones are safe with your doctor. Do not bundle a baby in blankets or heavy clothing. Infants don't tolerate heat well because their sweat glands are not well-developed.
Some people perspire more than others.
Those who do should drink as much fluid as they can during hot, humid days. Know the signs of heat stroke and heat exhaustion and don't ignore them. Until emergency care arrives, it is important to lower the body temperature. Place the feet higher than the head. Fan the person.