It's just the start of summer, but already a record-breaking heat wave has parts of the country, with temperatures soaring to 120 degrees or more.
That is dangerously hot.
Extreme heat kills more people than hurricanes, floods, tornadoes and lightning combined, according to the National Weather Service. A heat wave is loosely defined as two or more days of excessively hot weather. But any prolonged period of temperatures greater than 90 degrees is risky because it taxes the body's ability to maintain the safe internal temperature 98.6.
Drinking water is the most important thing to do during a heat wave.
The rule of thumb is to drink at least two liters a day to stay hydrated. Do NOT wait until you feel thirsty. And avoid caffeine, alcohol and sugary drinks because they cause you to lose more body fluid.
Look out for these four subtle signs of dehydration during a heat wave:
Color of Urine: When your hydration status is good, your urine will be clear to light yellow. The darker the urine, the more dehydrated you are. Drink up when your pee is darker than usual.
The "pinch" test: When your body's cells become depleted of water, the skin loses tension. Test the elasticity of your skin by pinching the back of your hand and hold it for a few seconds. Let go and if the little "tent" stays pinched and takes more than 5 seconds to go back to normal, it's usually a sign of moderate dehydration.
Bad breath: Bad breath should make you think about dehydration during a heat wave. If you don't drink enough water, and you're losing water through sweating, your body can't make enough saliva, meaning your mouth is dry and bacteria grow easily.
Sitting in front of a fan: New evidence has shown that when temperatures rise above 95 F, an electric fan might actually make you even hotter, by blowing hot air on you, making you unable to sweat.
And not being able to sweat puts you at greater risk of dehydration and even heat exhaustion. If possible, air-conditioning is the best choice. Cool showers and baths work, too.
Don't forget your pets: Make sure they have enough fresh water to drink and limit their exercise. Keep in mind that the asphalt or other surfaces get extremely hot during a heatwave which could make it painful for them to walk on.
Also, watch out for water in garden hoses: it can become extremely hot and cause severe burns.