To the Editor:
Annex A6.18.1(1) to the National Fire Protection Association (NFPA) 1582 Standard, which describes the mandated fitness level for diabetic firefighters, states that “a 12 MET stress test is required because myocardial infarction remains the major cause of line-of-duty fatalities, and diabetes is a risk factor for myocardial ischemia, especially silent myocardial ischemia.” Thus, the stated reasoning for a minimum 12 MET stress test as a fitness-for-duty examination is to rule out silent myocardial ischemia in a diabetic firefighter. It would be counterintuitive to assume that it is acceptable for the nondiabetic firefighter population to achieve less than the same 12 MET stress test fitness level during a mandatory yearly aerobic capacity fitness for duty test for all firefighters.
While working with the firefighter population for this study, I discussed this issue with Dr Richard Gerkin, the cardiologist who wrote the stress test protocol that is incorporated in the NFPA 1582 Standard. I questioned whether Dr Gerkin's protocol was the best means to judge the cardiac fitness of a firefighter with a 12 MET requirement. My concerns were based on Table C.220.127.116.11.1. in the Annex, which shows that a firefighter reaches the 12 MET (42 mL/kg/min) plateau a mere 3 minutes into the test. Dr Gerkin verified the 12 MET minimum requirement by explaining that the 3-minute warm-up period at 3 mph, plus the additional time needed to increase the treadmill speed up to 4.5 mph to begin stage 1, means that the actual plateau is reached closer to 9 minutes into the test.
I can understand your concerns with respect to the realities of applying this requirement in an actual workforce. However, the Howard County Fire Department is a living example of the achievement of this department-wide fitness level. When I worked with the Howard County Fire Department from 2007 to 2009, I was able to align the incentives of the local stakeholder groups to achieve general agreement that this fitness level was both attainable and in the firefighter's self interest. Of the 252 firefighters in the department, only three were unable to meet this requirement. Even the principal investigator, a middle-aged, overweight physician, was able to achieve this fitness level.
With respect to the group's remaining concerns, I believe that it is helpful to apply some context. The Howard County Fire Department is a strong municipal organization that has been focused on the health of its firefighters for some time. This group of firefighters was a preselected, relatively fit population before I arrived and had already been following the 2003 NFPA standards with a mandatory yearly 9 MET fitness for duty stress test for years. In addition, the department has better-than-average fitness resources, including gymnasium equipment in the firehouses, voluntary personal trainers, dietary counseling, and a smoking cessation program.
I arrived at the Howard County worksite with 4 weeks' notice. The 2007 NFPA standard, including the mandatory 12 MET fitness for duty stress test, had been implemented a few weeks prior to my arrival. Therefore, this endeavor was truly my attempt at a research effort given a real-world health initiative that had been recently modified by only one variable near the time of my arrival. This one variable was the change from the mandatory 9 MET fitness for duty stress test to a 12 MET test.
The data for this research project were provided to me by a fire department official and included monthly numbers of recordable injuries as well as the cost figures for those injuries. I was forced to use the data that were available rather than any idealized measures. However, the fact that the data points were assembled by persons who had no idea that a research project was under way was actually a plus. I stand by the data, particularly the significant decrease in number of department-wide recordable injuries over the 21 months of the study. Indeed, a case could be made that the progression in this decrease between years 1 and 2 could be explained by a dose response. I understand that the overall parameters including body mass index and blood pressure did not show a similar expected reduction, except in a couple of extreme subgroups. My explanation for this result is that the study was not allowed to continue long enough to document these changes in a selected population of firefighters who had already been required to perform yearly 9 MET stress test fitness-for-duty examinations. Twenty-one months into the initiative, I was transferred to a different work location and was therefore unable to gather as much data as I would have liked to document these outcomes. One could argue that the impressive reduction in the recordable injury rate that the study documented, which was highly statistically significant, was due to other unknown factor(s). I readily acknowledge this possibility. However, it also seems intuitive that one consequence of a workforce population that achieves a mandatory increased yearly fitness level could be fewer recordable injuries.
I can only hope that other fire departments will attempt to replicate these results by means of similar efforts going forward. If these results are replicated, it would constitute a valuable reaffirmation that a mandatory 12 MET stress test, used as a fitness for duty achievement test, is significantly more beneficial in preventing recordable injuries in firefighter populations than a similar 9 MET fitness-for-duty test.
Marc Leffer, MD, MPH, FAAFP
Federal Occupational Health Department of Health and Human Services Bethesda, MD