At a time in life when many start to slow down, legendary singer Joan Baez remains a whirlwind of activity.

At 77, the folk music icon is promoting her new album "Whistle Down The Wind" and has extended her final concert tour, the Fare Thee Well Tour, into 2019. Last year, the silver-haired singer was inducted into the Rock & Roll Hall of Fame and her rendition of "The Night They Drove Old Dixie Down" was featured in the movie "Three Billboards Outside Ebbing, Missouri." Baez has also added painting to her resume, often showing her work at Mill Valley's Seager Gray Gallery.

So what is Baez's secret to aging with grace? She has some natural advantages, such as good genes from her mother, who lived to be 100. But she also takes pains to eat healthy, such as harvesting the eggs from her own backyard and she pursues a rigorous fitness schedule. She also has the courage to let go of the past, embracing the way her voice has shifted over time. But Baez says the real key to staying fit enough to pull off a worldwide tour at her age is a posture and movement system called the Gokhale Method that soothes her neck, shoulders and back.

"People are always asking me how I stay in good shape," says Baez, over the phone from her home in Woodside. "And I actually do a lot of things like yoga and Pilates and meditation, but for me, the posture work is at the base of all of it. It's at the core of everything."

Baez says perfecting her stance has been the key to conquering her neck problems, which flare up because of the time she spends holding a guitar for long stretches on stage. She has had to learn how to sleep and walk and move with the proper alignment to keep her body limber.

"Basically the whole thing is lengthening the body and depressing the spinal column," says Baez. "It's a very hands-on discipline and you work with a mirror so you can see what you are doing. Whenever I go on tour, I backslide and the old habits creep back, so when I get home I go back to the source."

That's where her old friend Esther Gokhale comes in. The popular posture guru, who was trained as a biochemist at Princeton University and studied at Stanford's medical school, has been working with Baez for 10 years, helping her fine tune her alignment.

"It has helped her become pain free," says Gokhale, who teaches her method at a Palo Alto studio, "which is crucial when you are performing on stage and it can be difficult to control the tension in your body."

Gokhale, who patterned her method after the way people stand in other cultures such as India, describes Baez as a very disciplined and committed student, as well as a powerhouse personality.

"She's really very delicate but she's got this big persona, a big voice in a little body, says Gokhale, author of "8 Steps to a Pain-Free Back." She's also very down-to-earth and real. She's so present to life."

Born on Staten Island in 1941, Baez first became famous as an activist-singer in the '60s. By the age of 22, she was known as "the queen of folk singers" and she continues to perform songs of protest in the Trump era.

In recent years, however, Baez, has been struggling to come to grips with her changing voice after singing for 60 years.

"Aging, it's just one insult after another, isn't it?" she says with a chuckle. "I've had problems with my voice as I've gotten older, which all singers have. You can't hit the high notes the same way. You just can't."

Back in her '30s, the legendary singer asked her vocal couch how she would know when it was time to quit. He said her voice would tell her. Now, she says, it finally has. Her rich soprano tones, once so soaring, don't quite reach the heights they once did.

"I've had to reinvent myself and get to the point where I am happy with my sound now," she says, "even though it's not the original sound."

Vocal issues helped fuel her decision to make this her last official tour. Of course that means Baez will finally have time for other things. She has long been known for her political activism, a lifelong passion, and painting has given her new energy.

"I feel lucky to have found something I yearn to do at this period in my life," she says. "I love painting. I'm just gaga over it."

Visit The Mercury News (San Jose, Calif.) at www.mercurynews.com