In her 40s, Dierdre Wolownick taught herself to swim. In her 50s, she took up running. Then, at 60, she became a rock climber — and not just any rock climber. Four years ago, at 66, Ms. Wolownick made a record-breaking ascent up El Capitan, Yosemite National Park’s granite monolith that has some of the longest, most challenging rock climbing routes in the world. And she did it in style. The route she tackled then, Lurking Fear, typically takes four days to complete. Ms. Wolownick did it in one.

Of course, it helped that the author and now-sponsored athlete had one of the most accomplished rock climbers in the world to guide her: her famous son, Alex Honnold, the star of the 2018 Oscar-winning documentary “Free Solo.” The film chronicles her son’s breathtaking journey to become the first person to climb “El Cap” with no rope or safety equipment whatsoever. Her own effort — which did use ropes — was “by far” the most demanding thing she had ever done, Ms. Wolownick said.

Reaching the summit of El Capitan in 2017, she became the oldest woman to make that ascent, according to Hans Florine, an American rock climber with a record 179 climbs of the vertical rock formation.

And she has not slowed down. In late September, Ms. Wolownick returned to El Cap without her son to climb it again, this time to celebrate her 70th birthday with a small group of friends and guides. On that adventure she went up an easier route that climbers typically use to descend. It took her six hours to reach the summit, and after camping there overnight, came down in six and a half hours the next day.

The grueling climbs were a departure from the first half of Ms. Wolownick’s sedentary and cerebral life. Growing up in New York, she painted and played the piano in Jackson Heights, Queens. As an adult she taught five languages and wrote books, including a 2019 memoir, “The Sharp End of Life: a Mother’s Story,” in part about her first El Cap ascent. In 1990, a few years after moving to suburban Sacramento, where her husband grew up, she founded an orchestra in West Sacramento and conducted it.

“These were wonderful, greatly satisfying things but nothing was really physical. There certainly was no danger,” she said. “I never in a million years thought that I could climb El Cap.” (The following interview has been edited and condensed.)

Why did you start climbing?

Alex has always loved it. He was often very quiet, even morose as a child, but he would talk about climbing. The sport has real jargon — they say things like “jugging” and “rapping” — and I had no clue what he was saying. It pained me that I couldn’t relate to him over this. I figured I would try it so at least we could talk.

How did you try it?

About 10 years ago, Alex was home with an injury so I asked him to take me to the climbing gym. I figured I’d get to know the equipment and climb halfway up the wall and come home and be happy. I got on the first climb and went all the way up, about 45 feet, and I was totally surprised I had no fear whatsoever. So I did 12 more climbs that day and loved it.

What was your life like before that?

Total turmoil. My husband, Charles, fell over dead at 55 in the Phoenix airport one month after I had divorced him and I became the executor of his estate. My father had just died and I was dealing with his estate, too. Alex had almost died while snowshoeing in 2004 when he was 19. So I started running, little by little, and wound up becoming a runner. There was nothing in life I was doing for me and running was for me. Climbing turned out to be the same, an escape, but it took courage.

How did you overcome the challenges to climb?

Climbing is very physical and there’s so much to learn about the equipment, the physics, the angles — everything.

I was just a lumpy old middle age woman completely taken with jobs and chores. I was scared, too, and sometimes you need a little help to do something totally new and alien to you. But after a month or two I had had enough conversations with myself and so I said, OK, today, you’re not going home after work. You’re going to go straight to the climbing gym. And I did. It became a routine. Climbing was like a key opening this lifelong door. It was wonderful.

How did you prepare for El Capitan?

I went to Yosemite to train three days a week for 18 weeks in a row. I would hike and climb. I’ve never been able to do push-ups or pull-ups so I got one of those pull-up bars you can put in a doorway and started working on it. Every time I walk by it, I do 10 pull-ups. I’m up to about 50 pull-ups a day now. They’re not pull-up-from-the-ground pull-ups, but nonetheless, for me, they’re extraordinary. Climbing Lurking Fear was still the hardest thing I’ve ever done by far but just being on El Cap is a mind-bender. Your life changes.

How has climbing changed your life?

I learned how to suffer through all kinds of discomfort because what you get from it makes it worthwhile. It’s the same for anybody who wants to follow a path of bliss. There’s a lot of suffering. With climbing, you just have to deal. It’s not like you can say, ‘oh, it’s raining, let’s go back to the car’ when you’re 2,500 feet up. It’s such a privilege to be up there. Climbers get to go to the most unimaginable, beautiful, inspiring places, and the only way to experience them is to put in the hard work.

What would you tell people who are stuck or scared to make changes that might be good for them?

You first have to figure out why you think you can’t do something and ask yourself if that’s a valid point. Look, there’s somebody telling you every step of your life what to eat, what to wear, that you can’t sleep without this drug, and it’s all nonsense. You can decide for yourself what you think you’re capable of. It’s just so sad when people say, oh, I’m 50, I can’t … fill in the blank. Try it anyway! Who cares! You might be surprised.