Sister Madonna Buder, 87, is known as the “Iron Nun” for good reason. She’s a Roman Catholic nun originally from St. Louis, who at 75 years old, became the oldest person to complete the IRONMAN World Championship in Kona, Hawaii. That’s a 2.4-mile swim, 112-mile bike ride and 26.2-mile run.

She didn’t start racing until she was 48. However, since then, she’s completed more than 340 triathlons and 45 full Ironmans.

So, how did she get her start? According to her article on Prevention.com, it was at the recommendation of a priest.

I started running decades ago after a priest talked about its benefits for the body, mind, and soul—how it harmonizes all three. That’s what caught my attention. I remember thinking at the time, “I’m not just a head or a heart or a physical piece. I’m a whole piece. And if it doesn’t work together, you get off balance.” That’s what inspired me to start running—which led to racing triathlons—and I think it’s what’s kept me hooked all these years.

Although busy with a constantly-changing schedule, Sister Buder squeezes bits of activity into every part of her day.

Once I’m out of bed, the first thing I do is run to mass. Literally. It’s about 4 miles, round trip. From there, I might run errands—again, running from one place to another to log miles. Almost every day I run to the jail, where I visit with inmates. When the weather is nice, I’ll bike about 45 miles roundtrip to a lake near me and then swim about a mile or so. Because I never really know what my schedule will look like—I do a lot of volunteer work and end up going where I’m needed rather than sticking to a set itinerary—I squeeze in my workouts whenever I can and wait for nature to tell me what to do. But I do run every day, and I swim about three times a week.

Ever since Nike created an ad with Sister Buder as the featured athlete, she’s been gaining national attention.

She went on ABC’s The Doctors in November to discuss her “anti-aging” mindset.

“I think the secret is not to think about how old you are because your mind, your thoughts, control who you are,” she said.

What will you be doing in your 80s? It’s certainly worth thinking about.