Dr. Joshua Greenberg is the creator of the film “Postures for Life.”

Dr. Joshua Greenberg, a retired cardiologist, has more than 45 years of experience in the medical field. While the longtime Hopkinton resident has saved countless lives during that time, he more recently put his heart into sharing the restorative benefits of yoga on the big screen.

He created “Postures for Life,” a 30-minute documentary on how yoga has transformed his life and the lives of five others as they confronted challenging times.

The film will be shown at the Elm DraughtHouse Theatre in Millbury on June 9 at 6 p.m. All proceeds will go to supporting a nonprofit Greenberg created called Postures for Life Inc. Its mission is to provide yoga to the underserved and people recovering from cancer or substance use disorder. Doors open at 5:30 p.m., and a panel discussion will follow the film screening. Tickets are $33.85 and can be purchased online at this link.

In a recent interview with the Independent, Greenberg discussed how his son’s athletic pursuits led him to begin practicing Bikram yoga. More commonly known as hot yoga, it is a more physically demanding practice.

A native of Allentown, Pennsylvania, Greenberg worked in Worcester. He spent the first two-thirds of his career at UMass Memorial Medical Center and the latter third at St. Vincent Hospital.

“Twenty years ago or so, I became acquainted with yoga,” he said. “It was a very stressful time in my life. The yoga was very helpful in navigating the difficult times.”

This was about the same time he and his family moved to Hopkinton. It was close to his job in Worcester and not too far from his wife’s legal practice in Boston.

Greenberg stumbled into the discipline in an unusual way.

“My son was a high school athlete,” he explained. “I asked what more he could do in terms of weight training to help along his career. And the coach said, ‘You may think this is strange, but I think he would benefit more from doing yoga.’ ”

Greenberg called a yoga studio in Auburn recommended by the coach. When the receptionist asked about him, he decided to try it alongside his son.

“He didn’t like it, but I found it very relaxing,” Greenberg said. “I went back several times that week and got more and more involved with it until I practiced it every day.”

Eventually, his son reconnected with yoga, and Greenberg shared that he is training to become a yoga instructor.

Because of the calming nature of yoga, Greenberg said many of his classmates would chat after class. That was when the doctor began to ask them about what yoga has done for them “in terms of their personal troubles or difficulties.”

“I became so interested in their stories that I wanted to film them,” he said. “So I got a little video camera from Best Buy and started filming interviews with people doing their yoga postures.”

After being told his work was understandably “amateurish,” Greenberg “decided to take it to the next level.” He engaged a professional film editor and photographer to help him with his project.

The pair worked on the film for a decade, hindered in part by the pandemic.

“It was not my full occupation by any sort of the imagination,” Greenberg said with a smile.

Greenberg’s main goal was to bring the stories of these people’s physical and mental transformations to a wider audience.

“I felt somewhat concerned,” he said. “If I was going to bring this movie out into the open, I didn’t want to be profiting from people bearing their souls to me about yoga.”

This prompted him to create the nonprofit to help those who could not afford yoga classes to have access to the healing potential. While it has been in effect since 2015, Greenberg said it “only really got underway within the last couple of years.”

“Yoga tends to be seen as sort of upper-crust socially because of cost consideration,” he explained. “What we do with the nonprofit is to bring yoga to the people where they are and teach gentle yoga.”

Hour-long classes are conducted at the Worcester Family Resource Center and at Shrewsbury’s Independence Hall, a veterans residential recovery home.

“One of the things that I think is so important about yoga is the mind-body connection that it creates,” said Greenberg. “By focusing on the breath, it enables people to get out of their heads, so to speak. It clears the mind of the brain chatter.”

He added that yoga stimulates the parasympathetic nervous system and increases tone of the vagus nerve, the largest nerve in the body.

While he stressed that yoga is not a cure-all, he cited studies from Harvard Medical School and Johns Hopkins University showing that people who practiced yoga had improved cognitive function, mood and heart health. Yoga also can improve balance, flexibility and strength and can alleviate symptoms of back pain and arthritis.

“A major point of the film is that it’s following the stories of six individuals, myself being one of them, with various types of challenges,” said Greenberg. They include substance use disorder, obesity, grief and depression. While most of the people are from Worcester, one was from Portsmouth, New Hampshire. The film was shot at yoga studios in both locations.

Greenberg has been publicizing “Postures for Life” at area yoga studios and is contemplating taking it to other venues in MetroWest and beyond as well as potentially online as a pay-per-view movie.