3 Olympians on how they’re changing their training to adjust to extreme heat

As temperatures around the world continue to rise, athletes are preparing to compete in hot weather.

Earlier this year, inside a small “heat acclimation chamber” at a London university, the temperature was cranked up to 95 degrees Fahrenheit while runners trained on treadmills. They were preparing for the Marathon des Sables—an ultramarathon that covers 160 miles over seven days in the Sahara Desert. It’s an extreme event. But it’s the type of training that’s becoming increasingly common for any outdoor athlete as the planet heats up.