Many people have a preconceived image of what a typical runner should look like. But runners come in all shapes and sizes.

Mirna Valerio, who detailed her path to a life of running in her blog Fatgirlrunning, aims to encourage others to enjoy running, regardless of their size.

During the past 12 years she has finished ten marathons and 14 ultra-marathons — races that go beyond the standard marathon distance.

Her inspiring story has featured in many newspaper and magazine articles, and in TV reports. She has a published memoir called A Beautiful Work in Progress.

An REI-produced short documentary film about her called The Mirnavator went viral. She uses the nickname ‘The Mirnavator' as she continues to encourage others, regardless of their body size, to enjoy running.

In the documentary, which has been viewed 1½ million times on YouTube, she said: “I love my body the most when I am out running. Even if I am having a hard day. I feel strong and powerful, and in that I feel beautiful.

“I never thought I could run 18 miles one day, and then ten the next. But I can.”

During the film she is seen competing in a 50K off-road ultra-marathon.

“Trail running is really hard. It's not an easy thing for me, but I love that about it — that it's not easy, but I'm still able to do it,” she said

“I do it because I want to show people it's possible. I may not be fast, I may be the last person, but for me that doesn't matter.”

She has a strong social media presence, and as she was completing the final portion of the 50K event she checked e-mails on her phone. One of the messages was from someone who called her “a liar and fraud”, saying “a true professional runner is not overweight, which is what you are. You want to further fat-acceptance and people to kill themselves in your perverse idea of beauty”.

She questioned why someone would reach out and say that, and want to intentionally hurt people.

“I'm not a fraud. I run. I run slowly, and sometimes I walk, but I run,” she said. “And I'm a big girl, but that doesn't have anything to do with anything. I still get out there and run. I do what I need to do.

“This [e-mail] guy had one idea of what a runner should look like — and that people who had my body type, or body weight, really shouldn't be out there.”

Valerio added: “I know the truth. The truth is I'm a runner, I'm not a fraud. So I chose to focus on that and the good things that came out of the race.”

At school, Brooklyn-born Valerio played lacrosse and field hockey, earned a music scholarship, and went on to work at boarding schools. She also put on weight.

In 2008, she had a health scare; an anxiety attack that felt like a heart attack. She got checked out by a cardiologist. The experience led her to start running again. She began by doing one mile runs on a treadmill. As time passed her love of running stuck. She increased her maximum distance to 5K, then 10K and eventually ran a marathon.

She didn't stop there. She challenged herself to go further, doing ultra-marathons way beyond the 26.2 miles of a marathon.

Valerio is a former educator, and cross-country coach. She runs every day and competed in the 2018 Boston Marathon. She is also an event speaker and author.

In November, in a Women's Health article, she said: “I want everyone, everywhere to find joy. I want others to share my enthusiasm for the sport. Know that regardless of what kind of body you live in, you belong out there as well.”

She particularly loves running on trails and in nature. She was chosen as a 2018 National Geographic Adventurer of the Year, and as a Garmin Woman of Adventure.

In a short video for Garmin, which shows her running through forests, mountains, and in a road race, Valerio said: “Running is my therapy, my leisure, my lifeline. It's not about losing weight, it's about gaining life.

“This body is fierce, beautiful and unapologetic. Why in the world would I want to change that. I'm an ultra, unstoppable woman of adventure.”

• Mirna Valerio has a website at https://themirnavator.com/ which also links to her Facebook, Instagram and Twitter.