Sweat poured down her face. Her lungs burned. Her legs protested.

“I have to make it a mile,” she thought to herself as she pushed forward.

She did, in 17 minutes, 45 seconds.

That’s what the screen read on her living room treadmill when Mirna Valerio finished that mile back in 2008.

A former athlete—once a field hockey player in high school who was no stranger to running—she felt shaken by the shape she found herself in by the time she was 32. Tipping the scales at more than 300 pounds on her 5-foot-7 frame, Valerio knew it was time to make significant changes in her life, but it all started with that mile.

“That mile was pretty painful,” she says. “I was so occupied every single moment of every day, I didn’t realize how out of shape I had gotten. I had to walk most of it and it felt really bad.”

The thing that motivated her to get on the treadmill that day was even more serious than the disappointment of poor fitness though.

“Do you want to live to see your son grow up?”

That’s what the cardiologist asked her when she showed up at the emergency room with shortness of breath. Her son, Rashid, was just 5 at the time.

While the health scare ended up being attributed to stress—she was working crazy hours and found herself catching nearly every illness Rashid brought home from daycare—blood tests indicated that she had significant arterial inflammation. That appointment with the cardiologist was all she needed to inspire her to make a change.

“I knew I could do better,” says Valerio, who is now the director of Equity and Inclusion and a Spanish teacher at a boarding school in Rabun Gap, Ga. “I knew that my health needed to be a priority for my son. I was like, ‘You know what, I need to get my mojo back.’ So the next couple of weeks, my only goal was to get on the treadmill and get my mile time down. I worked toward that goal, running a mile a day, four to five times a week.”

She also enlisted help from Nikki Buccello, her friend and colleague at the The Purnell School in Pottersville, N.J., where they worked at the time. They were both looking to lose weight, so they started running, doing yoga and playing tennis together. They also began signing up for 5K races, often two per weekend.

“Once we made up our minds about pursuing exercise, we were constantly pushing each other,” Buccello says.

“For me, it wasn’t about weight loss, but just feeling better,” Valerio says. “That summer I lost 27 pounds. That was the start of things.”

A health scare help give Mirna Valerio a wake-up call in 2008 and she’s never looked back. Photo: Kim Cook

By “the start of things,” she means not just the beginning of better health through an active lifestyle, but also the realization that her story and struggles resonated with other people in a very real way. As she began signing up for longer races, including marathons and ultramarathons—she has completed nine of each—she began blogging about her adventures to keep her family and friends updated on the latest races for which she was training.

With her “Fat Girl Running” blog, she soon discovered people outside of her immediate circle were reading her reports and ponderings about running. They were instinctively drawn to the stories and adventures of a heavier-set African-American woman who dared to run great distances and train on the singletrack trails and the back roads of the rural South. All of which she did with supreme wit and perspective. She began getting calls from national media outlets and soon found herself being recruited to write for magazines and serve as a sponsored athlete for several notable running brands.

Now happily weighing around 245 pounds, her path to becoming not only a runner, but an ultra-distance athlete, speaks to runners of every shape and size. She has shattered the stereotypes of the waif-thin harrier, showing that all different body types belong in the sport. Her easygoing attitude and confidence in who she is makes for a level of authenticity that serves to inspire others.

“If I’m a bigger girl, I’m a bigger girl—I’m still active,” she says proudly. “I just love this lifestyle I’m living. My goal is simply to have longevity and lifetime health.”

She points out that her blood pressure and cholesterol levels are within healthy ranges, and while she may be classified as “bigger,” she feels it is her body’s natural set point. Using weight as the only indicator of health or a person’s ability to be an athlete is short-sighted, she suggests.

“There’s too much attachment to a certain set of values to a person’s weight. We really have to get rid of that type of thinking because it doesn’t make any sense,” she says.

With that said, Valerio isn’t training with the goal of sending a message to haters and naysayers. She’s just loves to run, and if doing it helps model healthy behavior and good self-esteem, then all the better.

“There are a lot of us out there—people like me who are bigger and don’t have the athletic-looking body, but are still athletes,” she says. “We are out there not because we are trying to prove anything, but because we just love it.”

And there’s no question that she loves it.

“Mirna can run distances I would never consider attempting and she just gets better the longer she goes,” Buccello says. “She loves being outside in nature. That’s what motivates her.”

Having run 25Ks, marathons, 50Ks and 100K races, in addition to Tough Mudder mud-obstacle races, Valerio is currently training for the daunting TransRockies Run in August. A grueling event that involves six days of running from Buena Vista to Beaver Creek, Colo., runners cover 120 miles and 20,000 feet of climbing.

Remarkably, despite Valerio’s intimidating race resume, she is constantly convincing other runners and aspiring runners to train with her. Rebecca Smith, a former colleague at Rabun Gap, is one of them. She says that while she was a runner in high school back in the early ’90s, she developed a number of stress fractures and long ago abandoned the sport. It was Valerio who lured her back in 2013.

“She got me training appropriately with the right gear, and between her and a physical therapist, I haven’t had those problems re-occur. I thought I had chronic pain issues with my shins and wouldn’t ever run or be in shape again and she totally changed my mind about that,” she says. “Mirna convinced me to try my first endurance race—a 12-hour overnight event—in the summer of 2015, where I completed my first marathon distance.”

After that, Valerio talked her into doing a 24-hour race, a 50K and a Tough Mudder.

“She is a great coach who motivates anyone who wants to workout with her,” Smith says. “She’s realistic about training and expectations and not pushing too hard too fast, but also encourages you to accomplish more than you thought you could. And then she pushes you to own the things you’ve accomplished.”

Valerio’s engaging personality and positive message earned her a chance to become an athlete ambassador for Skirt Sports, a women’s apparel brand that embraces the notion that runners come in all shapes and sizes. Photo: Kim Cook

Not only is Valerio inspiring scores of adult runners, she also continues to have a significant influence on the students she works with. In addition to starting the cross country program at Purnell, she currently serves as the varsity cross-country coach at Rabun Gap.

“She’s just one of those teachers that kids constantly want to be in the company of, so starting to run gives them an excuse to hang out with her,” Buccello says. “She has this infectious spirit and the kids are always excited to workout with her.”

“I try not to harp on the idea of having a good body image with the kids I work with, I just try to demonstrate it,” Valerio says.

It is this role modeling of being comfortable in her own skin that strikes a chord with many. She says that often it’s not what others say and do that limits potential, but our own beliefs about ourselves and our own potential.

“She is a shining beacon of acknowledging the struggles of body image and working to redefine what fit looks like,” Smith says.

“She introduced me to the joy of the workout selfie and sharing your accomplishments with others,” Smith adds. “The selfie is a way to say, ‘I am here, I am important, I am taking care of myself, and I am powerful, no matter how glamorous, sweaty, tired or disheveled I look.’ She has moved me closer to being happy with the body I occupy, rather than longing for the string-bean body I used to have as a teenager.”

“I call her my inner warrior,” Buccello adds. “Her pace is always focused and determined. She has this attitude of, ‘There’s a goal I want to achieve, these are the steps I need to take to get there, and nothing is going to stop me.’ She knows that there will always be obstacles, but she’s determined to keep moving forward no matter what.”

It is Valerio’s love for the sport and her fervent commitment to an active lifestyle that drives her. Right now, she says that she “finds inspiration in seeing how far her body can take her in terms of mileage, altitude, across mountains, whatever it may be—I just want to know how strong my body is, so I’m going to keep pushing.”

How might others adopt this state of mind and level of motivation?

“All I know is that you have to put on your sneakers and head out the door,” Valerio says. “It’s all about taking that first step.”

Valerio hams it up with fellow Skirt Sports ambassadors. Photo: Kim Cook

Mirna Valerio’s Tips on Good Health and Running

1. Think of food as fuel: “You have to eat healthy food if you want to run well. It’s all about thinking about eating as a means to fuel for activity.”

2. Be patient: “Nothing is going to happen overnight. Sometimes it can take months to see a physical change. Know that even if your body might not look a whole lot different right away, you’re getting somewhere. If you train, over time you’ll get faster and stronger.”

3. Embrace discomfort: “A lot of people aren’t used to being sore, so they think something is wrong with them when they experience that discomfort and they stop exercising. A little soreness is good. Expect it.”

4. Keep weight loss in perspective: “If you’re looking to lose weight, keep in mind that all bodies are different and that we all metabolize food in different ways. I don’t have a scale in my house, but if it’s something that motivates you to keep running, that’s fine. Just make sure you strike a balance in terms of how often you’re weighing yourself, and always keep your larger goals in mind.”

5. Set long-term goals: “If you’re only running to lose weight, what happens when you lose that weight? Are you going to stop? I think you should always have bigger, more overarching goals related to lifelong health, with smaller goals along the way.”

6. Don’t be afraid to phone a friend. “You have to be willing to ask for help in whatever it is you want to do. If you need help, ask for it and don’t be ashamed of it.”

7. Tune out the haters: “All body types can be runners. Sometimes you just have to stop listening to yourself and others. Most of the time you are the one stopping yourself.”