Your head is pounding, your muscles are cramping, and your heart is racing. And that’s just the start of it. Heatstroke kills thousands of people every year, including extremely fit outdoor athletes, who can be overcome quickly and with little warning. In the first episode of our 2023 Summer Read series, we hear a story about that demonstrates just how easy it is to get overheated—and what science tells us about how we can keep our cool.

The Outside Podcast is made possible by Outside+ subscribers. Learn more about all the benefits of a subscription and subscribe now at outsideonline.com/podplus.