Indiana University has monitored local firefighters to find the past six months for a way to help lower the risk of heart attacks. The Indianapolis Star reports that researchers monitored the heart rates of 56 members of the Indianapolis Fire Department to determine which job aspects create the most dangerous stress. The study is funded by a $1 million federal grant.

The study showed that heart rates speed up on the way to a fire and take hours to return to a normal rate.

"A world-class marathoner might run 85% to 90%," Jim Brown, a visiting scientist at Indiana University who is leading the study, told the paper. "During a fire, firefighters' heart rates can approach 100% of their average maximum rate, based on age."

For example, a 54-year-old man has an average maximum heart rate of 166 beats per minute. During a fire, a 54-year-old firefighter's heart rate was measured at 172 beats per minute.

Research performed by the National Fire Protection Association and the Department of Homeland Security has shown that about 45 of the nearly 100 firefighter deaths in the line of duty every year are caused by heart attacks. In comparison, about 27% of deaths nationwide in 2004 were caused by heart attacks, according to the National Institutes of Health. In Indiana, 13 of the 33 firefighter deaths in the line of duty since 1994 were attributed to heart attacks.

The study also found that:

• Firefighters' hearts react immediately to changing conditions. Heart rates spiked when a dispatcher informed firefighters that a family was trapped in a burning house.
• The risk of heart attack remains high for several hours after a fire.
• Among the tasks a firefighter performs, rescuing a victim is the most strenuous. Fighting a fire puts the second-most strain on his or her heart.
• The job taxes hearts even when firefighters are not working. Firefighters sleeping at the fire station had higher heart rates than when they slept at home.
• Excessively hot or cold weather heightens the risk of a heart attack.
• Volunteer firefighters are at a higher risk for heart attacks than professional firefighters. Inconsistent training regimens are suspected to be responsible for the difference.

Brown will present his findings to the Federal Emergency Management Agency and fire officials across the country. Dr. Kirk Parr, a cardiologist with the Indianapolis Care Group, believes that the findings could potentially lead to improved firefighting strategies, such as rotating firefighters more frequently during a fire. The study already has led to changes in training regimes in Indianapolis, where firefighters have shifted from aerobic-based exercises to anaerobic — such as weightlifting — which are similar to the types of work performed on the job.

Brown hopes to expand his research to fire departments in other cities to compare the effects of different routines, equipment and climates on firefighters' hearts.