About 400 deaths in the U.S. each year are caused by extreme heat--nearly half from weather, the CDC reports. Heat exhaustion, which induces dizziness, nausea and heavy sweating, can progress to heatstroke, when the body's temperature rises to 104 degrees Fahrenheit or higher.
How to avoid it: Limit most activities to early morning and evening and take hourly breaks in the shade, Beers says. Drink water regularly, or beverages with sugar and electrolytes if activity is prolonged, Gardner adds. Never leave a child alone in the car, even with the windows slightly open--temperatures can rise by 20 degrees Fahrenheit within the first 10 minutes, the CDC says.
How to treat it: Air conditioning and a cool drink for mild dizziness, fatigue, headache or stomachache. Call 9-1-1 or go straight to the ER if your child faints, is breathing unusually fast, has a rapid pulse or heart rate or is confused or disoriented. "Children suffering heat stroke will need intravenous fluids and should not be given anything to drink," says Beers.