The brain is one of the most vital organs in the body, and taking care of it is necessary to maintain focus, feel your best mentally and live a long life.

Longevity researcher Dan Buettner, who popularized the term “blue zones,” discussed how to “hack your brain for a longer life,” in a recent episode of his podcast. In conversation with psychiatrist Dr. Daniel Amen, Buettner asked Amen to share the biggest mistake Americans are making when it comes to their brain health.

“They don’t think about it. They never really develop a relationship with [their brain],” Amen said. “And it’s arguably the most important relationship you will ever have.”

Even after years of training to become a psychiatrist, Amen admits that he didn’t focus enough on his brain health until 1991 when he started offering brain imaging at his clinics. Amen scanned his own brain and learned it wasn’t very healthy.

“In 1991, I’m already a double board-certified psychiatrist. I’m a physician. I was the top student in neuroscience and medical school, and I didn’t care about my brain that much at all,” he said.