You're going to run a marathon in what?

When Irene Sewell, then 25, heard about a woman in London who kickboxed daily and had attempted to run a marathon - both in high heels - she had two thoughts.

"So weird," and, "Pssh, I could do that."

In 2015, that London woman made it only to mile 7 of 26.2 before she kicked off her heels and completed the marathon barefoot, thus not becoming the world's first person to run a marathon in heels.

Now 27, Sewell wants that title for herself. And this October, in an effort to get her name into the "Guinness Book of World Records," she will attempt to run Chattanooga's 7 Bridges Marathon wearing a pair of size 7.5 patent leather, open-toed pumps.

The shoes are true stilettos with a 2.75-inch heel and a .5-centimeter diameter, dimensions dictated by the Guinness World Records. Before a person can get his or her name into the book, the to-be-attempted feat must be approved by the organization. Hopefuls must create a profile, write a bio and list the record they hope to set or break.

"My bio was super-short. It just said, 'I'm a former professional ballroom dancer, turned runner, turned triathlete. If anybody could do this, it's me,'" Sewell says.

Four months later, her application was approved.

Sewell has always loved being in the spotlight.

"When you're competing, especially in ballroom dancing, you're on the floor with so many other couples. You have to do something to get people's attention," Sewell says.

She began dancing at age 5, taking tap, ballet and jazz classes. By high school, she was competing in regional dance competitions. As a freshman at the University of Tennessee – Chattanooga, she discovered ballroom dancing, and for the next five years, Sewell both taught and competed in national ballroom dancing events through the Fred Astaire Dance Studio. That meant spending 8-10 hours a day in high heels, she says.

In 2013, Sewell retired from dancing - but not the spotlight. She started to run for exercise, and within two months, she signed up for her first marathon.

Then, in 2015, she signed up for Chattanooga's half Ironman. In the following years, Sewell competed in three marathons and three half Ironmans, finishing them all. Though, she admits, "I'm not fast. I'm not breaking any records or placing in my age group."

Her goal was never to win, but to have an interesting story.

"Three years ago, it was an interesting fact that I'd done a half Ironman. It was still new to the city back then. But now everybody knows somebody who's done it," Sewell says. "I had to figure out my next thing,"

What better way to stand out, Sewell decided, than to be spotted at the gym or on the Tennessee Riverpark running in high heels?

In May, following her third half Ironman, Sewell took a month to recuperate. Then, she began to train for the 7 Bridges Marathon.

Irene Sewell is attempting to be the first person to complete a marathon in high heels. She will make her effort at the Seven Bridges Marathon in October. Ms. Sewell was photographed on the Walnut Street Bridge and at Coolidge Park on July 9, 2017.

"I was on the treadmill at the gym and the managers came up to me and said, 'Miss, did you forget your tennis shoes? Are you going to hurt my equipment?' I just told them I was going to attempt to break a world record and I just needed to run a few miles. Could I please? And they were like, 'Oh, yeah. Go for it!'" Sewell says.

Outside the gym, the most common reaction she gets from passersby is for them to stop and take pictures.

"I just wave and say, 'Hey!' and start to take pictures of them, too," says Sewell, who, before the big day, plans to increase her mileage in heels to at least 10. "When I have a goal that I'm chasing," she says, "nothing is going to stop me."

Except, perhaps, physics.

Sewell says the first time she ran in high heels was terrifying - especially going downhill.

"You're already pitched forward. It's hard to offset that," says Sewell, who eventually learned that if she splayed her feet outward, she could get more grounding. Moreover, she says, prior to running in heels, she had been a heel-striker, meaning she hit the ground with her heel first.

"You can't do that in heels or you're definitely going to break the shoe," says Sewell, who again had to adapt her form. However, one benefit she found was that, in heels, she couldn't slouch. "You're forced to have good posture, and that makes your gait better and helps you breathe better," she says.

Aside from proper form, the course itself, which takes runners across the Tennessee River six times, will pose more challenges to the stiletto-wearing runner. First, Sewell must cross the Market Street Bridge, which is grated. Next is the Walnut Street Bridge, comprised of soft wooden planks. Both are ideal surfaces to get a heel stuck.

"Pretty much, I won't be able to drop my heel at all. I've been practicing running on the balls of my feet," Sewell says.

Having to run on her tip-toes during certain stretches of the marathon will add even more stress to her feet. In a high heel, the bones of the foot are already forced into a more vertical position. When Sewell first began to train, she says she experienced a lot of pain on the tops of her feet due to that pressure. She visited a podiatrist who told her two things.

"She said I didn't have any stress fractures and she said she'd thought she'd heard everything," Sewell says.

Fortunately, that pain has since subsided, and Sewell now takes extra precautions to protect her feet. She pads her pumps with insoles, applies blister band-aids to trouble spots, tapes beneath her shoes' ankle straps and wears compression socks.

While her podiatrist never told her not to attempt a marathon in high heels, Sewell says, plenty of others have.

"My mom is as supportive as a mom can be, but she's like, 'Do you have to try? Can you back out? I wish you just wouldn't do it,'" Sewell says.

As a health care recruiter for a local physical therapy company, Sewell says she has mixed support from her colleagues.

"They're either super-supportive or their physical therapy brains are going, 'That's a really bad idea. You're going to hurt yourself.'"

But Sewell isn't worried about injuring herself, at least not during the race.

"Broken bones heal, that's fine, whatever," she says.

Her biggest concern is an injury that prevents her from ever making it to the starting line.

"I've put myself out there. Word is out. I have an Instagram page. I just need to be able to get to that line and do my best," says Sewell, who will have two support runners with her on marathon day, each carrying several spare pairs of those patent leather, open-toed pumps.

That finish line may still be miles away, but Sewell has already set her sights on her next big goal.

"Figure bodybuilding. I would have to be super-disciplined and drastically change my body. I think that'd be cool," she says.