On a recent foggy morning in the mountains of rural Georgia, Mirna Valerio was doing what she loves: running. On this particular morning, she led a small group of women on a jog across the picturesque campus of the Rabun Gap-Nacoochee School, a prep school where she works as a teacher.

The women diligently followed her lead as she changed course, uphill and downhill, pounding the pavement despite the muggy conditions. Most of the women said they were there because of Valerio.

Mirna Valerio runs through a forest. NBC News

"I didn’t do much running before meeting Mirna," said one, while another credited Valerio with "always getting us going."

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Valerio, 39, does not fit the mold of a cross-country runner. She is overweight and keeps a slow pace as she methodically traverses mile after mile. She says when passersby see her running, they see "a fat girl running" and she’s comfortable with that label and even embraces it. When she started a runner’s blog in 2011, she aptly titled it "Fat Girl Running."

It was not until a July 2015 profile in Runner’s World, however, that she became a well-known figure in the running world. The article sent a flood of traffic to Valerio’s blog. Runners of all shapes, sizes, and genders expressed their solidarity and support.

Overnight, Valerio became the voice for a whole class of athlete. "I too am a 250 pound runner," wrote one reader. "And examples like yours make that a little easier."

"Mirna, you have no idea what you have done to inspire literally every woman, not just women of size, but every woman to get out there and accomplish and achieve," wrote another.

Mirna on her morning run. George Itzhak

For those uninitiated in the world of distance running, Valerio’s accomplishments are impressive. Her own personal record is 35 miles, a run that took her more than 13 hours to complete. She admits it sounds crazy — doing anything for that long — but says she is drawn by a love the outdoors and a passion about the challenges that long distance running brings.

Valerio was not always an avid runner. In 2009, she weighed more than 300 pounds. She says she often suffered from sharp chest pains, signs that led her doctor to issue her a blunt warning: She would not live to see her young son grow up if she didn’t lose weight. That scare set her in motion on to the path where she finds herself today.

She took up running. Getting on the treadmill for that first mile, she says, was slow and painful. She clocked in at 17 minutes, 45 seconds. Within the course of the next six to seven months, she lost 41 pounds.

Mirna reaches a peak at the end of her run. NBC News

Miles don’t phase Valerio now. She says she craves the physical, emotional, and mental challenges of getting through a 26.2 mile marathon — a physical feat hardly matched in all of sports.

Next month, she will run the Javelina Jundred, an annual 100k race in the Arizona desert. Despite the impressive mileage she clocks, her weight remains mostly stable.

Valerio knows most people view her as fat. And she has no problem with that.