James Kirkland started his career in 1982 as a geriatrician, treating aging patients. But he found himself dissatisfied with what he could offer them.

“I got tired of prescribing wheelchairs, walkers and incontinence devices,” recalls Kirkland, now at the Mayo Clinic in Rochester, Minnesota. He knew that aging is considered the biggest risk factor for chronic illness, but he was frustrated by his inability to do anything about it. So Kirkland went back to school to learn the skills he’d need to tackle aging head-on, earning a PhD in biochemistry at the University of Toronto. Today, he and his colleague Tamara Tchkonia, a molecular biologist at the Mayo Clinic, are leaders in a growing movement to halt chronic disease by protecting brains and bodies from the biological fallout of aging.