Hundreds of people in Philadelphia will strap into indoor cycles on Saturday and Sunday with the area's hottest spin instructors.
It's a big workout to benefit young hearts being treated at Children's Hospital of Philadelphia's Cardiac Center.
We introduce you to one teenager who is grateful for that care.
15-year-old Jackson Debusschere always dreamed of being a pro athlete.
"Six out of the 7 days out of the week, I'd be playing soccer and also ice hockey, too, full time," he said.
That wasy, until 2 years ago when got sick - fast.
"It started out with just a little tickle cough," he recalled.
"In less than a week, he went from intense training for ice hockey and soccer every day to being in complete heart failure," said Jackson's mom, Kira Debusschere.
His parents rushed him to Children's Hospital where he immediately went on life support, while they performed more tests.
"They said it's worse than we thought - it's this giant cell myocarditis," said Jackson's dad, Dave Debusschere.
Jackson's heart muscle was dangerously inflamed due to a runaway immune system.
"The body's own inflammatory cells decide to attack itself, and in this case, it attacks the heart muscle," said Dr. Matthew O'Connor, Cardiologist at Children's Hospital.
Dr. O'Connor says the trigger is still uncertain - it could be an ordinary virus. To save Jackson, he used a trio of drugs to control the immune attack.
"You try to shut down the immune system enough to stop the inflammation," he said.
Jackson spent 2 weeks on life-support.
"I woke up and thought it was just one night's sleep," he recalled.
Since then he has slowly improved. Contact sports like soccer are out, though he can referee hockey.
Now, he's aiming for a college scholarship in golf. He says his drive is his best part.
"Worst part? Chipping, by far," he said with a laugh.
This is only the third year for the Spin-In, but it just keeps growing.
This year, a Saturday evening session has been added to handle all the instructors and riders, but there are still a few spots open.
All of the proceeds go to Cardiac Center research, to find answers to problems like Jackson's.
For more information and to register for this event, CLICK HERE.