The US is facing a major heat wave this weekend - here's what extreme heat does to the body and brain

The US is headed for a heat wave.

Across most of the US, as President Obama warned Wednesday, there's expected to be extreme heat.

And while it may feel like you're literally melting, there are actually some pretty interesting things that are going on inside your body when it's faced with extreme heat.

To get some answers, Business Insider spoke with Matthew Cramer, a researcher at the Institute for Exercise and Environmental Medicine in Texas who studies the effects of heat on the body.

Here's what goes down.