Melissa Mitchell, News Editor
(217) 333-5491; melissa@uiuc.edu

11/1/2001

Photo by Bill Wiegand UI kinesiology professor Steven J. Petruzzello and a team of researchers have been measuring and studying various physiological responses among firefighters. The most significant problems are caused by heat strain and stresses to the cardiovascular system.

CHAMPAIGN, Ill. — Since the Sept. 11 attack on the World Trade Center, images of exhausted firefighters have been imprinted on the national psyche, increasing public awareness of the arduous nature of rescue workers' jobs.

And while operations in New York City were an extreme example of what firefighters face when responding to an emergency, researchers at the University of Illinois' Fire Service Institute know that even routine rescue operations can pose serious health risks for firefighters. The most significant problems, they say, are caused by heat strain and stresses to the cardiovascular system.

"What kills firefighters most is heart attack," said UI kinesiology professor Steven J. Petruzzello, who, along with a team of researchers at the Institute, has been measuring and studying various physiological responses among firefighters. Is it part of continuing stress over time that leads to these incidences? Petruzzello's not sure, but he says long-term research may eventually prove such a link. What is known at this time, however, he said, is that "the percentage of firefighters or former firefighters who die of heart attacks is more than the general population."

When it comes to heat strain, Petruzzello said, it's long been suspected that firefighting activities result in an imbalance in fluid and electrolytes. To better understand just what was happening, Petruzzello and colleagues Denise L. Smith, Mike A. Chludzinski, John J. Reed and Jeffrey A. Woods tested 11 firefighters at the UI training facility, documenting their findings in a report published recently in the Journal of Thermal Biology.

"The purpose of this study was to determine the effects of strenuous live-fire firefighting drills on selected hematological and blood chemistry variables and to document the extent to which these variables recover following 90 minutes of recovery," the researchers write in the report. They also documented firefighters’ perceptual responses to repeated trials of the same firefighting activities.

Besides recommending that firefighters drink plenty of water after completing an operation, the UI researchers stress the importance of drinking six to eight glasses of water daily.
"As a nation, we are underhydrated for the most part," Petruzzello said. "This study emphasizes not just rehydration but prehydration. After rehydrating, firefighters don't get back to baseline levels immediately. It's similar to an athlete going through a long-distance run. You can never drink enough to recoup losses from that activity."

Another important finding of the study, he said, is that blood glucose and sodium levels decreased dramatically following the participants' 90-minute recovery period. "Given the muscle's need to resynthesize glycogen, and the fact that firefighters may be called upon to respond to another call, it may be beneficial for firefighters to consume a carbohydrate/electrolyte beverage in addition to aggressive rehydration following a strenuous bout of firefighting activity," the researchers wrote.