Dr. Kirk Daffner, 61, paused briefly to center himself before he began the first of more than 108 carefully orchestrated maneuvers. He lunged, rolled, did one-armed push-ups and slapped the mat with his open hand. He jumped in the air spread-eagled, touching his feet, then grunted as he kicked at an unseen foe, his hands balled into fists or fingers extended, chopping the empty air.

He, along with a handful of other men, have been practicing routines like this for more than 40 years, under the careful supervision of George Gonis, who runs the small, second-floor gym where they sweat off several pounds during each 90-minute session. All have been training in the ancient Greek karate style known as pankration with Mr. Gonis, some on and off, since their teens or early 20s.

Dr. Daffner, a neurologist and expert in aging at Harvard Medical School, considers Mr. Gonis a second father. He concedes that despite his degrees, years of training and global reputation, his karate teacher has always known more about healthy aging than he does.

“His views about how to maintain health and how to promote good aging were really decades ahead of his time,” said Dr. Daffner, chief of the division of cognitive and behavioral neurology and director of the Center for Brain/Mind Medicine at Brigham and Women’s Hospital.

Not just the physical exertion pankration requires, but also the mental fortitude and way of life the practice fosters — especially as done by Mr. Gonis — have increasingly been shown in studies to be vital for aging well. “I regret the fact that I wasn’t smart enough to listen to exactly what he was saying,” Dr. Daffner said.

The scientific world has finally caught up to Mr. Gonis, said Dr. Daffner, who recently threw his mentor a 90th birthday party in his Newton back yard for current and former students. Attendees included a plumber, a bar owner and a Boston Fire Department chief.

Mr. Gonis, who practiced law for several years before turning to karate full-time, has always advocated for fitness, along with a Mediterranean-style, plant-based diet and intellectual stimulation. “I don’t drink, I don’t smoke, I don’t do drugs, I never did,” Mr. Gonis said after the recent Wednesday night class.

The bookshelves in Mr. Gonis’s office remain stacked with textbooks, including calculus and ancient Greek philosophy, and he has always required his students to write papers about the philosophers. “The brain is part of the body,” Mr. Gonis said.

Each series of Greek karate maneuvers, such as the “form” Dr. Daffner demonstrated recently, tells a story from ancient Greece. His moves that night illustrated Odysseus returning from a 20-year-long voyage and then fighting off the 108 suitors who wanted to claim his wife, Penelope. To Dr. Daffner, presenting the form is an act of beauty as well as a mental and physical challenge.

Of course, there are many ways to age gracefully, and one man’s health at 90 isn’t proof of anything. But Dr. Daffner said he thinks Mr. Gonis’s continued strength — he can still outlift students who are decades younger — is about more than luck. Mr. Gonis’s parents and sisters all died in their 70s.

“I am both amused and pleased that so many of the things we now know are really good for us, he knew,” back in the 1960s and 1970s, Dr. Daffner said.

Dr. Daffner said he uses his karate skills every day, in the self-control he has learned to exert over his body. “Training the body is really about controlling the mind,” he said.

Studies confirm that such work has implications for healthy aging. Conscientiousness, which reflects the tendency to control impulses and be goal-directed, has been linked to a substantial reduction in the risk of cognitive decline late in life. Other research on successful aging emphasizes the importance of self-efficacy, or belief in one’s own abilities. Successfully learning and completing the forms helps build self-esteem, Mr. Gonis said.

For decades, though, Dr. Daffner would listen to Mr. Gonis’s ideas about aging well, then turn back to his patients and his research on interventions for healthy aging. “He kept encouraging me to study exercise and brain health. I didn’t take his research advice too seriously,” Dr. Daffner said.

Now, Dr. Daffner said, Mr. Gonis’s voice remains with him as he designs his research. A few years ago, he investigated the potential impact of exercise on brain health, he said.

More recently Dr. Daffner, inspired by his ancient Greek karate training, decided to test how all these positive steps work together, encouraging trial participants to exercise, participate in mentally challenging activities, and eat a healthful diet. The latest research suggests social connections are important as well, so the trial also promotes social engagement for participants.

In his own life, Dr. Daffner said, karate has provided him with close ties to Mr. Gonis and with friendships that have lasted decades.

“To be successful, interventions for healthy aging need to include all of these components,” he said.