For most of her life, Eva Steinwald thought Mount Everest may as well have been the moon.

An Idaho-based real estate broker, she was an avid skier, sometimes a jogger, and a black-belt karate instructor, but never considered herself an athlete.

Then her husband Pat died in 2018. After more than two decades of marriage, she told Business Insider she decided to re-envision her life with the biggest challenge she could think of: overcoming a fear of heights to climb literal mountains.

At age 63, she stood at the top of Everest after only a few years of climbing experience and set a record as the oldest American woman to summit the world's highest peak.

Now 64, she works out six days a week to take on the rest of the Seven Summits, the highest peaks on each continent.

Steinwald said she learned late in life how to revitalize her fitness. She said the same principles that help her tackle the toughest environments on the planet can help even fitness newbies get in better shape.

"I feel great. I have energy. I'm strong," she said. "People look at me, and they don't think I'm 64. This is just normal for me."

Her four-part exercise plan mirrors longevity advice from top doctors, performance scientists, and elite athletes. Scale it to your fitness level and schedule to build a better workout, whether you want to take on big adventures or extend the healthy years of your life.

Strength training boosts long-term durability

She started with obstacle course races, where she quickly realized she needed to build up some strength and hired trainers to help.

Her current regimen includes three days a week of strength training. Extensive research shows strength is key to both athletic performance and a long, healthy life, alongside mobility.

Steinwald works with a coach from Stretch Lab to prevent injury and protect her muscles and joints. She spends two sessions on lower-body exercises and one on upper-body and core exercises, with a focus on balance and stability movements.

Slow, steady cardio to build a better engine

Steinwald's first major peak was Mount Rainer in Washington State.

She took on the grueling hike, followed by a freezing climb at midnight (when the ice is more stable), after a crash course in using an ice ax, crampons, and other gear.

Reaching the top as sunrise broke over the horizon, Steinwald decided she couldn't get enough.

To build her stamina for bigger adventures, she took on "a lot of boring endurance runs," she said.

Her weekly training includes running at an easy pace for an hour or two at a time.

The idea is that slower Zone 2 cardio sessions allow your body to adapt at a pace you can more easily recover from. For beginners, that can be a fast walk or a light jog for 10-20 minutes, building up.

"You have to take little baby steps," Steinwald said. "Don't be hard on yourself, get back up and do it the next day."

Rucking supports real-world fitness

To prepare for the strain of hauling gear up rugged cliffs, Steinwald spends long hours carrying a weighted pack. Also known as rucking, the exercise has caught on for performance and longevity because it combines strength and cardio at once.

When the weather doesn't cooperate, Steinwald gets it done in the gym. A recent session involved two hours on the stair stepper, then two hours with a heavy pack on the treadmill, while watching movies to pass the time.

She recommends sticking to a similarly rigorous schedule, even if your workouts are shorter.

"Put it on your calendar, and it is non-negotiable. It is your time. It is your health physically and mentally," she said.

Interval training develops resilience

The last ingredient in Steinwald's exercise potion is a sprinkle of high-intensity intervals, like uphill sprints. She started small, with about 30 seconds of sprinting at a time, but has worked up to 10 minutes at a fast pace on an incline — brutal even for an experienced athlete.

The shorter, speedier sessions help raise the body's ability to handle hard effort over time.

Intervals also cultivate psychological grit, teaching you to problem-solve under strain.

Steinwald said it's a key lesson for taking on literal mountains, where you can fail despite your best efforts.

"It's not about the summit. When you climb these mountains, it's really about the journey, discovering yourself and your strengths, your weaknesses," she said.

Steinwald said an unexpected perk of her mountaineering is emotional fortitude and a greater sense of being present in everyday life. It's helped build closer relationships, which is another key factor in longevity.

"After going through all the pain and hard work on a mountain, really digging deep, you realize it's OK. You can thank someone, you can apologize. You can say, 'I love you,'" Steinwald said. "We don't share our emotions enough, and the mountains have really taught me you need to share."

This article is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your qualified physician or healthcare provider.