Searing heat is blanketing much of the U.S., putting millions in danger.
The majority of the country will see temperatures above 90 degrees, with heat indexes soaring to 110 degrees along the East Coast.
So what are the signs of heat stroke that you should know? Inside Edition asked Dr. Mehmet Oz for tips to recognize the illness.
First, he said, your skin will feel super hot, then that sensation will become painful. You'll get a headache and your heart will start to race as it tries to pump blood throughout your body to keep you cool. Finally, you'll start to pant as you try to rid yourself of excess heat.
Heat stroke can be deadly if not treated. So Oz advises staying out of the sun altogether this weekend. But if you must go out, make sure to drink lots of water, at least half a gallon a day — more if you're doing any kind of physical activity.
And while energy drinks might seem like a good idea, they won't hydrate you as quickly as water, Oz said.
He also recommends putting together an emergency kit for staying cool, complete with instant ice, water gel packs for cooling burned skin and a silver rescue blanket.