In May, Nick Gravina had a heart attack while on the job at his fire station in Parker.
He thought it was just a bad indigestion after eating a big meal following an intense physical fitness test.
"It just was like this stabbing knife right in my chest and I couldn't get it to go away. I just took some antacids and it just wasn't helping," he said.
His crew hooked him up to the station's AED and administered CPR for over an hour.
They took him to the hospital where a large blood clot was removed from his heart.
The physically fit firefighter wasn't in a high risk category and says it can happen to anyone.
He warns people not to ignore warning signs of pain.
"Get it checked out. It's way worth it. I wouldn't be here today if I would have ignored it, which I very easily could have," he said. "I was thinking about lying down and taking a nap to try and rest it off and if I would have done that I probably wouldn't be here."
Gravina has a wife and two young boys - ages three and six - who were glad to have him healthy for Halloween.
(KUSA-TV © 2012 Multimedia Holdings Corporation)