91-year-old completes her 15th marathon

It's always impressive when someone completes a marathon. The amount of perseverance and dedication required to complete 26.2 miles is very admirable. However, it's even more awe-inspiring when the marathoner is over 90 years old, a leading example of healthy aging.

Harriette Thompson, a 91-year-old from North Carolina, ran her 15th marathon in May at the Rock 'n' Roll San Diego Marathon. Thompson finished the race in seven hours and seven minutes, breaking the record for her age group. She was the oldest participant in this year's challenge and the second-oldest U.S. woman marathoner in history. Thompson falls in the age group for people between 90 and 94 years old. According to National Public Radio, her time this year beat the previous record holder by two hours.

Thompson began running marathons at age 76 and has only missed one year since, due to cancer treatment. She has had oral cancer and skin cancer. In fact, she finished radiation treatment for skin cancer on her legs just one month before the race.

According to The Huffington Post, Thompson has completed 393 miles of marathons while raising $90,000 for the Leukemia and Lymphoma Society's Team in Training. She has been personally affected by leukemia, having known several people who were diagnosed with the form of cancer, including her brother.

In an interview with NBC 7 San Diego News, Thompson said she had only run an 8k race in 2014 prior to this spring's marathon. The runner is also a seasoned concert pianist and told NPR that sometimes she thinks about Chopin etudes while racing to stay motivated. She remains active in her retirement community, with hobbies ranging from yoga and stretching classes to elliptical workouts.