A dangerous heat wave threatened a wide swath of the Southwest with potentially deadly, triple-digit temperatures. Some cooling centers extended their hours and emergency rooms prepared to treat more people with heat-related illnesses. Dr. Kristin Englund explains what will happen to your body when it starts to overheat. #heatexhaustion #heatwave #health Get a fast-paced look at the latest from the border to Main Street to the White House on "NewsNation Live with Marni Hughes." Weekdays starting at 10a/9C.#NewsNationLive NewsNation is your source for fact-based, unbiased news for all America. More from NewsNation: newsnationnow.com Get our app: trib.al/TBXgYpp Find us on cable: trib.al/YDOpGyG How to watch on TV or streaming: trib.al/Vu0Ikij