He loves training for them. He loves the freedom he feels while running. He loves pushing his body to the limits.
But most of all, he loves crossing the finish line.
"I cry every time," says Bell, 30, of Hoboken, New Jersey.
But what makes him so unique – and inspiring – is that he has cystic fibrosis, a life-threatening genetic disease that affects the lungs and digestive system of about 30,000 people. It was once considered a death sentence, with few people living beyond their teens.
While it's difficult for many with this disease to breathe, let alone exercise, Bell has shown others that not only can you live a normal life with cystic fibrosis, you can excel. He has run in eight marathons and can't wait to cross the finish line for his second half-marathon this year (his 15th total) on Oct. 12 in Staten Island.
And yes, there will probably be tears – but, he emphasizes, they are joyful ones.
"It's a celebration of the fact that I'm 30 years old, I can still breathe and my lungs still work as well as they do," says Bell, who works in advertising.
In 2008, Bell paired his love of running with his yearning to make a difference and teamed up with The Boomer Esiason Foundation, a nonprofit that raises money to find a cure for the disease.
His wife, Megan, whom he married last month, has run three marathons, and so have many friends and family.
Since then, he and his loved ones have raised $125,000 for the cause, Team Boomer's president, Michaela Seccareccia, tells PEOPLE.
Seccareccia still remembers the first marathon Bell ran for them when she asked each member of the group why they were running.
"When I got to Steven, he said, 'I run because I can,' " she says. " 'Some people even without CF can't run and I'm doing it because I can.' And I just love that."
She's not the only one who admires Bell.
Jen Caruso, mother to an 11-year-old son with cystic fibrosis, was moved to tears by Bell's speech at the foundation's annual gala in New York City a couple of years ago.
"I look at someone like Steve and I have a sense of calmness that things are going to be okay and my son can lead a very normal life," Caruso, 36, of Townsend, Delaware, tells PEOPLE.
Living with CFDiagnosed with cystic fibrosis at three months old, Bell never let it slow him down.
At age 5, he was on the soccer team, and at 6, he joined the swim team. After graduating from college, where he played soccer and was accustomed to exercising up to three hours a day, he needed a way to exercise without breaking the bank. He turned to running, and in 2007 he ran his first half-marathon in Philadelphia.
"I ran in four-year-old tennis shoes because I didn't know there were specific shoes for running," he says.
He runs five to seven miles every morning and does 45 minutes of treatments to clear his lungs of fluid when he gets up and before he goes to bed each day.
To him, this is normal – and he's grateful he's still breathing through his own lungs and hasn't yet had to have a lung transplant.
"I've never known what it's like to not do 45 minutes of treatment before going to bed, or eating a meal without taking a handful of pills," he tells PEOPLE. "All of these things are my normal."
And while you may think running would tax his fragile lungs, he says it's actually key to his staying healthy.
"From a health perspective, lifting weights strengthens the muscles, and running strengthens your lungs," he says.
Only recently did Bell realize he was an inspiration to those with and without the disease.
To him, it's all about the joy of crossing the finish line.
"It's a celebration of all the hard work that I put into everything I do," he says, "and that day, crossing the finish line is my reward."
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