ST. LOUIS (KMOX) - There are hidden dangers when it comes to extreme heat and they can be deadly.
Doctors say the extreme heat, like we are seeing these days, can confuse our brain, shut down your organs and overwork our heart.
"The danger is when you have heat and an environment that is very humid, so you want to be very cognoscente of that." said Wash U and Barnes Jewish emergency medicine physician Dr. Tiffany Osborn to KMOX.
The three big killers due to the heat and high humidity are heat stroke, heart attack and dehydration -- all caused by the dangerous affects extreme heat has on the brain.
"(The extreme heat) puts you in a situation where the amount of volume in your blood vessel is low and then your vessels can constrict properly," said Dr. Osborn. "So it makes it easier for you to pass out and that's why you get dizzy when you stand up (in the extreme heat)."
That's why it is so critical to stay hydrated during this heatwave.
"You want to make sure you are drinking a lot of water," said Osborn previously to KMOX. "Drink before we become thirsty because if you are already thirsty, you might be already behind. And if you know you are going outside or know you are, try to drink water the night and morning before you go out."