As I was preparing for an 850-mile hike across the desert, I emailed one of the world’s top performance scientists for training advice.

He ignored me completely.

Instead, he turned me into a guinea pig. “I know exactly what happens to most athletes,” he said. “But I have no clue what’s going to happen to you on that hike. I want to find out.”

He took blood, saliva, urine, etc 24 hours before the hike, 24 hours after, and 45 days later.

Today, I brought that scientist, Andy Galpin, on the podcast to talk about what he found.

We also covered what wearables get right and wrong, the 5-pillar exercise plan that makes a body ready for anything, an easy way to fix sleep, and more.

Watch or listen here: