At “Physiological Responses to Structural Firefighting,” Dr. Jim Brown shared what research on this topic has revealed so far. A six-month study of 56 Indianapolis (IN) Fire Department (IFD) firefighters conducted in 2008 examined the physiological stress associated with structural firefighting. Too little scientific literature exists about the rigors of firefighting, Brown said, but if we are to prepare firefighters properly to meet the challenge of fighting fire, we must know the extent and character of the stress they endure.
Certain variables were predictive of a firefighter’s response to suppression operations, and some of these can be modified. There are differences among fire scene jobs with respect to physical demand, and findings have implications with respect to fireground operational tactics and designing firefighter physical fitness training programs.
Brown noted that in the past 25 years, about 40 to 50 firefighters have died as the result of heart attacks annually. He outlined the findings several research projects including the 2008 Indianapolis study of real world firefighting. In one study, heart attacks accounted for 95 percent of firefighting fatalities. Of these, 44 percent had known cardiovascular disease (e.g., a previous heart attack, a coronary by-pass).
Another firefighter study revealed that, after 12 minutes of firefighting activity, physiological changes included reduced blood volume and increased platelet activity. Reduced blood volume affects the transport of oxygen and the body’s ability to cool itself. Platelets tendency to clump and therefore cause blood clots increases. All of these factors increase the risk of heart attack, especially in less fit firefighters, Brown said.
In the 2008 Indianapolis study, firefighters’ heart rate, breathing, and movement were continuously monitored while on duty. Researchers stayed at the firehouses involved for the duration of the study. At the presentation, Brown showed a video of an IFD response to a structure fire, where a mother and three children were reported trapped. He shared the physiological data for certain firefighters at the initial alarm, during the response, and after.
Firefighters should be familiar with the extent of physiological stress seen on the fireground, the primary contributing factors, and what can be done to alleviate that stress.
The amount of stress which firefighters may experience depends on numerous factors, include the number and frequency of responses, the size of the structure and the amount of fire encountered, the exertion expended, firefighting experience, and individual physical fitness. Also important to note is that the stress induced by firefighting activities may remain for some time after those activities are ended. After one response, Brown noted, firefighters’ elevated heart rates during fireground activities did not diminish even two hours after the end operations.
Brown noted that firefighters carry many of the hazards of fighting fire with them to the fireground. “Only firefighters can alleviate the extraordinarily high heart attack rate within their population. The responsibility for physical preparation lies with the individual firefighter. No department, union, or other organization is going to do it for you.”
Dr. Jim Brown is an applied physiologist with Firefighter Health and Safety Research at Indiana University.