'We're proving that this is a new door to understand cancer better': Tour de France coach Iñigo San Millán on what elite cyclists could reveal about cancer biology

The 111th edition of the world-famous Tour de France starts June 29 in Florence, Italy. This year, the grueling 21-stage bike race takes place over 2,175 miles (3,500 kilometers) across Italy and France.

Slovenian rider Tadej Pogačar of UAE Team Emirates is widely considered the favorite to win, having won the yellow jersey in 2020 and 2021 and finished second the past two years. Part of Pogačar's success comes down to Iñigo San Millán, who coached the champion cyclist for years as UAE Team Emirates' head of performance.

But in addition to being an expert in sports performance, San Millán has a second passion: He's hunting for new ways to beat cancer.  

As an assistant professor of medicine at the University of Colorado School of Medicine, San Millán has studied the interactions of cancer and lactate, a byproduct released by cells during regular metabolism — and in particular, by muscle cells during intense exercise like cycling. While elite athletes' bodies easily flush that lactate out of their systems, in people with cancer, tumors release huge amounts of lactate that then sticks around, spurring on the cancer. San Millán is investigating how to disrupt this vicious cycle. 

Live Science spoke with San Millán about his double life as sport performance coach and cancer researcher, discussing his work in both spheres.

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