This 102

When Dr. Gladys McGarey was 93, she awoke from a vivid dream one Sunday morning.

She was nine again, living in a tent in the jungle in India, where she grew up. She emerged from her tent in the early morning, looking mischievously to see if anyone was watching. When the coast was clear, she ran as fast as her legs allowed and climbed a mango tree. Once she got to the top, she sang. The song lyrics are hazy, but McGarey knew she was belting something fun.

"I’m singing any old thing that I want to sing, and having a great time," McGarey, who is now 102, tells Fortune. She recalls doing something out of the ordinary—because Sundays growing up consisted of specific hymns and rituals with her family. But she kept singing her own favorites.

"I was singing, and I was laughing at the same time as I woke up," McGarey says.

Called the mother of holistic medicine, McGarey co-founded the American Board of Holistic Medicine and ran a medical practice for over 60 years. She's also authored a handful of books on the science of healing and preventative medicine and continues to work today as a consulting doctor seeing patients about once a week.

Despite her career success, she didn't feel like she could always express herself.

"I didn't really find my voice until I was 93," she says, recalling how she struggled to write in elementary school and was called the "class dummy," due to her dyslexia.

But her dream reminded her it's never too late to shout from the tree tops—or in her case, write her wisdom from the heart.

At age 100, she began writing her forthcoming book, The Well-Lived Life. In it, McGarey explores how to find and cultivate purpose, and shares six secrets to health and happiness.

Here are a few words of wisdom from her well-lived life:

As an active centenarian, McGarey often fields questions about the secret to her longevity. Her son jokes about how his mother has a ten-year plan to this day. McGarey says her passion for learning and staying engaged with the world around her is thanks to her sense of purpose.

Conventionally defined as an intention, a purpose is the reason behind our actions. If something propels us forward, we find more meaning in what we do—whether a career, a set of values, a passion project, meaningful connections, or a way of life.

"It's that kind of finding out what it is that you can do and what your soul is telling you," she says. "You have got to do it."

Fortunately, it doesn't need to take years to find your purpose, and it's not merely a goal to check off the to-do list. It can lie in everyday activities that make you feel present or the small moments of joy we find outside work when we slow down. The connections in our life or a side-hustle can bring us a sense of excitement. And the answer is closer than many would think. It's about trusting your gut when something feels right, McGarey says.

"Look for what you can do, not what you can't do," she says, which looks different for everyone. "Our bodies are our teachers … if we pay attention to it, we learn lessons." It's true—when we engage in activities we enjoy, our brain rewards us with a release of dopamine or a rush of contentment.

McGarey recently learned about her great-grandson's Youtube channel, which has amassed thousands of subscribers to her amazement. It makes him happy, and McGarey says to search for whatever lights your candle, and gets the juices flowing—even if it's "wackadoodle."

"If you’re thinking that everything is done, that people have done everything that needs to be done or whatever, you won't find it," McGarey says, who may be one of the lucky ones having always known her purpose was to help people through the healing process as a physician.

However, she also faced immense change throughout her life—both for better and for worse—which changed her purpose, but taught her how to move with the tide.

McGarey lives by her mother's motto: make do. While simple at the outset, it holds the tools to help people accept pivots.

"It's that kind of ability to drop what you are thinking and move to the other place and be there at that other place," she says. "I don't think there are any people who have traveled this earth who haven't found themselves in places when they’ve been stuck for a while."

As a mother of six, McGarey says it was hard not to be in the moment and make do when changes arose. Whether it was something her kids needed or if a patient faced an emergency at work, she had no choice but to change course. She couldn't do it all and had to accept she would disappoint people along the way, including her children.

"I know there were times when they were upset about me not being there when they would want me to be there," she says. "But so what? I wasn't."

She learned to accept that her time and attention is limited.

The cliche motivational slogan "live, laugh, love," rings true for McGarey. She has led a life aimed at laughing out of love, and listening out of empathy. She advises people to slow down, listen to others, and laugh more.

"Laughter with love is happiness and joy," she says. "Listening with love is understanding."

The author walks a precise 3,800 steps a day, which she tracks on her phone. She routinely rides her "adult tricycle," as she calls it, around her yard and into town.

Maintaining a consistent movement routine helps when you enjoy the activity—something fitness experts agree on.

"I do things that I can do, that I want to do," McGarey says.

Both figuratively and literally, McGarey has paid attention to her dreams throughout her life and used them to calm her brain and stay motivated. Thanks to her nine hours of sleep, she catches many vivid dreams when the lights turn off.

And being able to find something that excites her has helped her chase and follow a purpose.

McGarey listens to the cues from her dreams, such as that little girl climbing up the mango tree, in hopes of her tune landing on the ears of someone who needs to hear it—much like her own message about aging and finding joy.