Nearly 50 percent of on duty firefighter deaths are heart related, according to the U.S. Fire Administration.
Cardiac deaths are the leading cause of death for on-duty firefighters.
The reason, it's a high stress job. “We go from a resting heart rate to a very high heart rate when that alarm goes on," explained Fire Marshal Chris Richmond, for the City of Springfield.
The other day, a Springfield firefighter was sleeping in the bunkers, the alarm went off, he ran to the call.
His heart rate jumped from 63 to 141 and it doesn't go down in the blink of an eye.
According to heart experts, whenever a heart rate makes a jump of that extent, it can cause problems.