Firefighter health and fitness assessment: a call to action.

FIREFIGHTER HEALTH A CALL TO ACTION

AND

FITNESS ASSESSMENT:

THOMAS W. STORER,1 BRETT A. DOLEZAL,1 MARLON L. ABRAZADO,1 DENISE L. SMITH,2 MAXIM A. BATALIN,3 CHI-HONG TSENG,4 AND CHRISTOPHER B. COOPER,1 THE PHASER STUDY GROUP 1

Exercise Physiology Research Laboratory, Departments of Medicine and Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California; 2First Responder Health and Safety Laboratory, Department of Health and Exercise Sciences, Skidmore College, Saratoga Springs, New York; 3Institute for Technology Advancement, Henry Samueli School of Engineering and Applied Science, University of California–Los Angeles, Los Angeles, California; and 4 Division of Biostatistics, Department of Medicine, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California ABSTRACT Storer, TW, Dolezal, BA, Abrazado, ML, Smith, DL, Batalin, MA, Tseng, C-H, and Cooper, CB; The PHASER Study Group. Firefighter health and fitness assessment: A call to action. J Strength Cond Res 28(3): 661–671, 2014—Sudden cardiac deaths experienced by firefighters in the line of duty account for the largest proportion of deaths annually. Several fire service standards for fitness and wellness have been recommended but currently only 30% of U.S. fire departments are implementing programs for this purpose. The Department of Homeland Security Science and Technology Directorate has initiated the Physiological Health Assessment System for Emergency Responders (PHASER) program aiming to reduce these line-of-duty deaths through an integration of medical science and sensor technologies. Confirming previous reports, PHASER comprehensive risk assessment has identified lack of physical fitness with propensity for overexertion as a major modifiable risk factor. We sought to determine if current levels of fitness and cardiovascular disease (CVD) risk factors in a contemporary cohort of firefighters were better than those reported over the past 30 years. Fifty-one firefighters from a Southern California department were characterized for physical fitness and CVD risk factors using standard measures. Overall, physical fitness and risk factors were not different from previous reports of firefighter fitness and most subjects did not achieve recommended fitness standards. Considering the lack of widespread implementation of wellness/fitness programs in the U.S. fire service together with our findings that low physical fitness and the presence of CVD risk factors persist, we issue a call to action among health and fitness professionals to assist the fire service in implementing programs for firefighters that

Address correspondence to Thomas W. Storer, [email protected]. 28(3)/661–671 Journal of Strength and Conditioning Research Ó 2014 National Strength and Conditioning Association

improve fitness and reduce CVD risk factors. Fitness professionals should be empowered to work with fire departments lending their expertise to guide programs that achieve these objectives, which may then lead to reduced incidence of sudden cardiac death or stroke.

KEY WORDS cardiovascular disease risk factors, line-of-duty deaths, risk mitigation INTRODUCTION

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irefighters in the United States have only average physical fitness and, of particular concern, have high rates of excess weight and obesity (11,16,17,22,25,35–37,47). These characteristics are incompatible with the well-characterized physical demands of firefighting. These include high-intensity work in thermally intense environments while wearing heavy (approximately 22 kg) and cumbersome personal protective equipment (PPE) and carrying and using tools needed to perform specific job tasks (8,10,16,17,22,25,36,39,43). In this context, suboptimal fitness and excess body weight result in a mismatch with the highenergy demands required by firefighters, a combination that may provide a trigger for sudden line-of-duty cardiovascular or cerebrovascular events (1). Indeed, recent data have revealed that these events account for about 49% of firefighter line-ofduty deaths (12) and remain the number 1 cause of firefighter fatalities (50,51). Lack of physical fitness and the deconditioning, which lead to overexertion plus unrecognized cardiovascular disease (CVD) risk factors, are among the prominent contributory risks toward line-of-duty injuries and deaths (12). A recent National Fire Protection Association (NFPA) needs assessment continued to emphasize the need for health and wellness programs and also reported that 70% of fire departments still have no such programs (33). Consistent with this finding, Soteriades et al. (42) reported that infrequent amounts of physical activity are common in the fire service and that most departments do not mandate regular exercise VOLUME 28 | NUMBER 3 | MARCH 2014 |

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Firefighter Health and Fitness training regimens or require maintenance of important fitness parameters. The reasons for lack of participation in medical assessment and wellness/fitness programs are complex, but guidelines for their development and implementation are available through NFPA standards for medical (NFPA 1582) (30) and health-related fitness programs (NFPA 1583) (32) and the Wellness-Fitness Initiative (WFI) developed by a Fire Service Joint Labor Management group (14). Despite these comprehensive guidelines, only 30% of U.S. fire departments have successfully implemented these programs (33). Recently, the Department of Homeland Security Science and Technology Directorate established the Physiological Health Assessment System for Emergency Responders (PHASER) program with the primary objective of assuring the health and safety of emergency responders (ERs) through risk identification, prioritization, and mitigation. Using an evidence-based medical model to identify and prioritize risk factors, the PHASER team has sought to determine whether physical fitness and CVD risk factors were substantially different in a contemporary cohort of firefighters compared with those documented in several reports over the past 30 years. We specifically chose to evaluate a Southern California municipal fire department that had no established fitness or wellness program. We hypothesized that these firefighters, on average, would exhibit levels of fitness and cardiovascular risk factors that are similar to the relatively low levels previously reported and not different form the average age-matched Americans. The specific aims of this study were to perform comprehensive fitness and cardiovascular risk analyses on our cohort and to evaluate their performance on these measures against previously published reports in firefighters and to reference values for healthy age- and gender-matched individuals. Anticipating that our hypothesis is confirmed, we propose a call to action for health and fitness professionals to engage with professional and volunteer fire departments to provide expert guidance in establishing and implementing wellness and fitness programs specific to the needs of firefighters.

METHODS Experimental Approach to the Problem

Study Design. The study was conducted with sworn personnel at 1 Southern California municipal fire department which serves a community of 67,000 people over 6.3 square miles. The fire department under study had no formal fitness program at the time of this investigation but had allotted 90 minutes per shift for individual exercise to all personnel. There was no regularly scheduled mandatory physical examination for firefighters leaving this responsibility to individual choice. To provide a comprehensive risk assessment, we measured standard indices of aerobic fitness, including body composition and muscle strength, along with traditional cardiovascular risk factors, such as resting blood pressure (BP), fasting blood glucose, and cholesterol, in volunteers at baseline.

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Subjects

A total of 51 ERs from 2 stations were eligible to participate. These included 47 career firefighters (1 woman) and 4 command officers: 3 battalion chiefs and the fire chief. Participation was voluntary with assurances of confidentiality. The study was approved by the UCLA Office for the Protection of Human Subjects in Research (Institutional Review Board), and all subjects gave written informed consent. Scheduling

All testing was done on 3 separate days after an introductory session by shift (3 shifts per station) and completion of the medical and exercise history questionnaire. The healthrelated fitness tests were completed on day 1, the cardiopulmonary exercise test (XT) was conducted on day 2, and blood sampling on day 3. All fitness testing was conducted at 1 station with appropriate environmental controls and privacy. Participants were tested during their work shift between 0800 and 1200 hours; prearranged coverage was provided in the event of a call. On a separate day, blood samples were obtained at each station between 0700 and 0800 hours after an overnight fast. Procedures

General Approach to Baseline Assessment. All subjects completed a medical and exercise history questionnaire. Resting heart rate and BP were obtained after 5 minutes of lying supine. Heart rate was palpated over 60 seconds and BP was obtained by sphygmomanometry by an experienced investigator. If a BP was more than 140/90, a second BP was obtained. Aerobic Performance

A maximal cardiopulmonary XT was conducted on a treadmill using an incremental walking or running protocol. These tests _ O2max) enabled accurate determination of aerobic capacity (V and the lactate threshold, a submaximal measure of aerobic performance, as determined by noninvasive gas exchange measurements described below (6). The choice of protocol was based on each subject’s exercise history, predicted aerobic capacity (6), and the objective of test termination in 8– 12 minutes (6). Three minutes of low-intensity walking served as a warm-up in both protocols. The walk protocol consisted of progressive 2% increases in grade each minute at a constant speed of 3.7 mph. The run protocol started at 5.0 mph and 2% grade with speed increments of 0.7 mph each minute. Because of prior injuries that precluded maximal treadmill testing, 3 subjects performed incremental cycle XTs consisting of 3 minutes of unloaded cycling and a 25 W$min21 work rate increment. Gas exchange was measured using a portable metabolic measurement system (Oxycon Mobile; CareFusion, Yorba Linda, CA, USA), which incorporated a turbine flow transducer, and discrete oxygen and carbon dioxide analyzers. Proprietary algorithms time aligned flow and gas concentrations breath-by-breath and displayed 8-breath rolling averages _ O2), _ E), oxygen uptake (V for pulmonary minute ventilation (V

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Journal of Strength and Conditioning Research _ CO2). A portable electrocardioand carbon dioxide output (V graph (ECG) was integrated with the metabolic measurement system to provide continuous 12-lead ECG tracings and heart rate. This combined unit was worn on the back and weighed 0.95 kg. We confirmed the accuracy of the Oxycon Mobile before exercise testing by validating it against our laboratory reference standard (Oxycon Pro; CareFusion). Blood pressure was measured by sphygmomanometry at rest, every 3 minutes during exercise, and throughout recovery. Subjects were tested wearing a T-shirt, shorts, and athletic footwear and encouraged to exercise to exhaustion. Maximum oxygen uptake was taken as the highest V_ O2 achieved during a 15-second measurement interval. We determined the lactate threshold graphically from gas exchange measurements first by identifying the _ O2 (6). point at which V_ CO2 increased more steeply relative to V When the metabolic threshold was uncertain using this rela_ O2) and _ E/V tionship, the ventilatory equivalents for oxygen (V _ E/V_ CO2) were examined for the abrupt carbon dioxide (V _ O2 without an increase in V _ E/V _ CO2. _ E/V increase in V Body Composition

Body weight and height were measured to the nearest 0.1 kg and 0.01 m, respectively. Percent relative body fat was determined with both bioelectrical impedance analysis (BIA; RJL Quantum II, Clinton Township, MI, USA) and skinfolds using skinfold calipers (Lange, Beta Technology, Santa Cruz, CA, USA) and standard procedures (48). Because hydration state has a marked influence on the BIA results, subjects were instructed to remain well hydrated and not exercise in the 24hour period before testing. Waist, upper arm, thigh, and calf girths were measured with a spring-indexed nondistensible tape measure using standard procedures (48). The same experienced tester (B.A.D.) performed skinfold and circumference measurements on all subjects. Percent relative body fat was calculated from the BIA resistance and reactance measurements and manufacturer-supplied equations. Generalized equations were used to estimate body fat from skinfold thicknesses taken at the chest, abdomen, and thigh for men using standard skinfold sites (48). Muscle Performance and Flexibility

Tests of muscle strength and endurance were conducted using methodology specified by the WFI, which is similar to procedures recommended by other authoritative groups (15,48) and included grip strength, push-ups, abdominal endurance, and the plank; a measure of core stabilization (14). Handgrip testing was used as a measure of strength because it is included in the WFI fitness test battery, presents low risk of injury, and because many firefighter “essential job tasks” specified in NFPA 1582 require grip strength, e.g., pulling hose, lifting and carrying heavy objects, and wielding an axe for roof or wall ventilation (30). For grip strength, the final score was taken as the best of 3 trials for both hands. The push-up test was administered using standard procedures with men positioned on their hands and toes (48). For the abdominal endurance test, subjects performed as

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many partial curl-ups as possible in 1 minute on a cadence set by an electronic metronome (15). The plank is a static “core” exercise in which the individual is required to maintain a horizontal position while resting on forearms and toes, while maintaining the back in a flat neutral position. Reference values are not currently available for this test. Hamstring flexibility was evaluated using the modified sitand-reach test (48). Pulmonary Function

A handheld spirometer (SpiroPro; ERT, Philadelphia, PA, USA) was used to obtain measurements of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). The ratio between FVC and FEV1 was also calculated. Standard guidelines (28) for test administration were used, in which each subject was given a minimum of 3 trials, with the better of 2 tests that agreed within 150 ml accepted as the final value. Blood Sampling

Blood sampling was performed by a certified phlebotomist after an overnight fast and analyzed for total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, triglycerides, and glucose. These data along with age, family history, cigarette smoking, physical activity, obesity, BP, and prediabetes were used to identify CVD risk factors (48). Statistical Analyses

Descriptive data are reported as means and SDs. Comparisons with selected test results were made against published age- and sex-specific reference values for the healthy population (48) and with weighted means from published firefighter fitness profiles (8–11,16,22,26,27,34–37,47).

RESULTS Demographics

Forty-eight uniformed personnel (1 woman) volunteered to participate representing a 94% participation rate. This included 44 firefighters and all command personnel. Reasons for nonparticipation beyond personal choice were not obtained. Data for the single female subject are not reported to protect her anonymity. The 47 men had a mean (SD) age of 43.1 (7.7) years, weight of 91.1 (13.3) kg, and height of 1.81 (0.07) m. When individual test results were compared against reference values for the apparently healthy population, appropriate sex-specific reference values were used (Table 1). Table 2 shows self-reported habitual physical activity for aerobic and resistance exercise training and flexibility exercise. Mean values for each of these types were lower than that recommended (20). Only 36% of the current subjects achieved 3 days per week and 30 minutes per day as recommended minimums for frequency and duration of aerobic exercise; 50% achieved the recommended $2 days per week frequency of resistance training. VOLUME 28 | NUMBER 3 | MARCH 2014 |

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TABLE 1. Demographics, physical fitness variables, and cardiovascular disease risk factors for 48 firefighters in the present study compared with published data from 13 studies on firefighters and reference values for age-matched healthy individuals.* Present study Mean

SD

Range

Published FF data† Weighted Weighted mean SD

Reference values N

Value

Age (y) Height (cm) Weight (kg) BMI (kg$m22) Relative body fat (%) Waist girth (cm)

43 1.81 91 28 20 96

8 26–56 0.07 1.65–1.98 13 70–122 3 23–36 5 11–30 9 78–120

37 1.78 89 28 23 97

8 0.07 15 5 8 12

SBPrest (mm Hg) DBPrest (mm Hg) HRrest (min21)

122 77 63

13 10 10

102–184 60–116 44–82

126 79 75

13 10 13

1,474 1,474 1,95

,120 ,80

(5) (5)

V_ O2max (L$min21) V_ O2max (ml$kg21$min21) V_ O2max (percentile) V_ O2u (L$min21) V_ O2u (ml$kg21$min21) V_ O2u/V_ O2max (%)

3.51 39.6 44 2.07 23.5 58

0.62 2.22–5.13 9.4 22–66 31 5–99 0.55 1.20–3.83 8.0 13–50 9 42–79

3 36

1 9

235 769

29 61

8 9

40 40

3.66 40.4z 50.0 1.51 21.6 61

(48) (48) (48) (7) (7) (6)

HRmax (min21) HRmax (% predicted) CI (L21)

175 98 39.6

14 6 9.9

182 99

10

160 120

220-age 100% 40 (M)

(48) (45,46)

Grip strength (kg) Flexibility (cm) Push-ups Abdominal endurance Core endurance (Plank, s)

117 33 37 47 107

15 8 16 23 47

87–147 13–47 9–71 5–75 24–180

112 34 35 43

19 7 17 11

255 115 353 64

110 39 16 39

(13) (15) (15) (15)

79 95 96

5 9 9

67–90 67–117 74–118

1 103 102

13 35

40 346 346

79 100 100

(19) (19) (19)

202 126 55 103 101

34 29 15 54 9

146–306 71–203 35–93 31–269 84–118

175 101 39 123

40 35 12 78

932 731 732 732

,200 ,100 $40

(31) (31) (31)

,100

(2)

FVC/FEV1 (%) FVC (%) FEV1 (%) Total-C (mg$dl21) LDL-C (mg$dl21) HDL-C (mg$dl21) Triglycerides (mg$dl21) Glucose (mg$dl21)

168–194 79–109

1,683 1,292 1,331 1,516 18.5–24.9 1,106 21.9 858 $102 (M); $88 (F)

Source

(55) (48) (18)

*FF = firefighters; BMI = body mass index; M = male; F = female; CI = chronotropic index; FVC = forced vital capacity; FEV1 = forced expiratory volume in 1 second; LDL-C = low-density lipoprotein cholesterol; HDL-C = high-density lipoprotein cholesterol. †References 8–11,16,22,26,27,34–37,47. zThis is the 50th percentile. Forty-eight percent of the individuals tested scored this level; 20% were below the 20th percentile, which suggests a sedentary lifestyle and increased risk of all-cause mortality (48).

Comparisons With Reference Data

Anthropometrics

Table 1 and Figures 1 and 2 present findings of this study and comparisons with fitness profiles derived from the weighted means from 13 previously published studies in firefighters (8–11,16,22,26,27,34–37,47). Reference values in the healthy population are also presented and are matched for age and sex of the present cohort.

Body composition and anthropometric measurements are reported in Table 1. Mean body mass index (BMI) for the current group was 27.7 (3.4) kg$m22 and therefore classified as overweight (OW) (55). Panel A of Figure 1 displays the distribution of BMI according to standard categories (55) and a group mean and a weighted mean for previously

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59% of the tests at end exercise. Those who did TABLE 2. Habitual exercise. not show clear evidence of a plateau achieved Aerobic training Resistance training Stretching .98% age-predicted maxid$wk21 d$wk21 Yes Percent d$wk21 mal heart rate and a peak R value .1.12. Mean 3.4 34.9 1.4 19 38 On average, values SD 1.4 13.0 1.2 Range 1–7 15–60+ 0–3 were at the 44th percentile according to 1 comNumber Percent Number Percent No Percent monly used reference 21 21 (48) with rankings rang22 44 ,2 d$wk 25 50 31 62 ,3 d$wk 3–4 d$wk21 10 20 2–3 d$wk21 25 50 ing between the fifth 5–7 d$wk21 18 36 .3 d$wk21 and 99th percentile (Table 1). Relative to body weight averaged 39.6 ml$kg21$min21 or 11 metabolic equivalents (METs, where 1 MET is 3.5 ml$kg21$min21). This average published studies (8–11,16,22,26,27,34–37,47). In the present value is about 6% below the recommended value of 42 group, 72% were classified as OW or obese. Mean values ml$kg21$min21 for firefighters (30,34). Thirty-three percent for relative body fat were in good agreement averaging _ O2max greater than this recomof the participants achieved a V 20.9% (5.7%) for BIA and 19.6% (5.0%) for skinfold measuremended value and 30% had V_ O2max scores below a suggestedments and were not statistically different (p = 0.08). Howminimal value for firefighters of 33 ml$kg21$min21 for ever, the level of agreement between these 2 methods _ O2u, above which reference (43). The metabolic threshold, V suggested an overall trend for BIA measurements to yield lactate accumulation occurs (6), averaged 137% of predicted higher values than those measured by the skinfold method. (7) and represented 59% of aerobic capacity. Expressed relative Panel B in Figure 1 illustrates the distribution of relative fat _ O2u was 23.5 ml$kg21$min21 or to body weight, the average V values based on percentile rankings and their corresponding about 7 METs (Table 1). categories (48). Using these criteria, 33% of the current samFigure 2A displays individual data for the association ple would be classified as having above average body fat _ O2max and age in the present study group, its mean between V compared with the reference population. Waist circumfervalue, and a weighted mean for this relationship in firefighters ence averaged 95.8 cm with a range of 78–120 cm. There as summarized from 13 previously published studies. Although were 8 individuals (18%) who exceeded a WHO upper limit the current group was older and somewhat more aerobically of 102 cm (55). fit, the age-related decline of 0.9 ml$kg21$min21 per year was about twice what was expected (6). Aerobic Performance Figure 2B shows the relationship between V_ O2max and Forty-one of the 48 participants completed a treadmill XT relative body fat indicating that higher body fat is associated and 3 individuals performed a cycle XT because of prior with lower aerobic capacity. It should be noted that when injuries that precluded maximal treadmill testing. Because body fat levels below 20% are achieved, more individuals are cycle exercise testing typically yields lower values for above the recommended V_ O2max of 42 ml$kg21$min21 for V_ O2max than those achieved during treadmill exercise, their firefighters and reflects the effect of excess body weight on aerobic function data are not included in the analysis. There functional capacity. were 54% of subjects who performed the treadmill test using the walking protocol. Two people did not participate in Cardiovascular Performance treadmill testing because of scheduling difficulties, and each Table 1 contains the cardiovascular responses at rest and one because of a recent injury or personal choice. Included in at maximal exercise during XT. Using current guidelines, the summary results are 2 tests that were terminated early because of either significant ST segment depression or the mean resting BP in this study would be considered prehypertensive, at least on the basis of the systolic BP serious dysrhythmias that was subsequently addressed by (5). Forty-six percent of the subjects would be considered confidential medical referral. Removal of these test data normotensive (BP ,120/80), 50% prehypertensive (BP = would have changed mean V_ O2max by only 0.06 L$min21. Mean (SD) test duration, maximum heart rate, and respi120–139/80–89), and 9% hypertensive (BP .140/90). ratory exchange ratio (R) were 11.2 (2.1) min, 175 b min21 Resting heart rate was within the expected range and max(14, 98% of predicted), and 1.16 (0.03), respectively. A imal heart rate averaged 175 min21 (14) representing 98% plateau in V_ O2 despite increasing work rate was seen in of age-predicted maximum (48). The chronotropic index VOLUME 28 | NUMBER 3 | MARCH 2014 |

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Figure 1. A) Body mass index (BMI; kilograms per square meters) distribution in the pilot fire department, n = 46. The boxes represent the BMI category range. The number within each box indicates the number of individuals in that BMI category. The dashed horizontal line is the mean BMI for the pilot group, 27.5 kg$m22. The dotted line represents a weighted mean BMI (28.2 kg$m22) in 13 published studies in firefighters (8–11,16,22,26,27,34–37,47). UW is underweight, DES is desired BMI, OW is overweight, OB I is class I obesity, and OB II is class II obesity. B) Categorical representation of relative body fat distribution in the pilot fire department, n = 45. Categories are based on age-specific percentile rankings and their descriptive categories (48). The boxes represent the range of values for relative body fat within each category with the horizontal bar indicating the mean value for subjects within the category. The number above each box indicates the number of individuals per body fat category. The dashed horizontal line is the mean % body fat for the pilot group, 19.9%. The dotted line represents a weighted mean % fat (23%) for firefighters in 13 published studies (8–11,16,22,26,27,34–37,47).

(CI) averaged 39.6 (9.9) L21, which is within the normal range Table 3. Musculoskeletal Fitness

Table 1 displays results of selected tests of muscle performance including 1 measure of isometric strength (handgrip), 2 endurance measures (push-ups and abdominal crunches), and a core stability test (plank). Handgrip strength and abdominal endurance scores were similar among the present cohort, previously reported data on firefighters, and reference values for an age-matched healthy population. Push-up scores among current and

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Figure 2. A) Individual values for maximal oxygen uptake (V_ O2max) in the pilot fire department by firefighter age. The blue star represents the mean V_ O2max for this group, 39.3 ml$kg21$min21. The red square indicates the weighted mean V_ O2max, 36 ml$kg21$min21, in 13 published studies in firefighters (8–11,16,22,26,27,34–37,47). The dashed horizontal line is set at 42 ml$kg21$min21, a recommended target V_ O2max for firefighters. In the current sample, 67% of the participants scored below this value. B) Individual values for maximal oxygen uptake (V_ O2max) in the pilot fire department relative to firefighter body fat. The blue star represents the mean V_ O2max for this group, 39.3 ml$kg21$min21 and the mean % body fat (19.9%). The red square indicates the weighted means of 36 ml$kg21$min21 for V_ O2max, and 23% body fat in 13 published studies of firefighter fitness (8–11,16,22,26,27,34–37,47). The dashed horizontal line is set at 42 ml$kg21$min21, a recommended target V_ O2max for firefighters.

previously reported firefighters were more than twice the scores of the reference population (48). The sitand-reach test, primarily a test of hamstring flexibility, was somewhat higher in the present subjects than in previous reports of firefighter fitness or in the reference population. Pulmonary Function

Pulmonary function as determined by FVC, FEV1, and the FVC/FEV1 ratio was essentially normal and represented 94, 96, and 101% of predicted values for age, height, and sex (19).

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TABLE 3. Traditional cardiovascular risk factors.* RF threshold (48) Traditional RF Age Family history Smoking Physical inactivity Obesity Prediabetes Hypertension Hyperlipidemia Subjects with 0 RF Subjects with 1–2 RF Subjects with $3 RF Additional risk factors Prehypertension (5) Exercise-induced hypertension ST segment depression V_ O2max ,20th percentile (48)

M $45 y; W $55 y Male 18 relative ,55 y or Female 18 relative ,65 y with MI, coronary revascularization, or sudden death Current, quit within last 6 y or environmental tobacco smoke exposure ,3 d$wk21 of moderate intensity physical activity of ,30 min$d21 BMI $30 kg$m22 or waist girth .102 cm (M) or .88 cm (F) FBG $100 mg$dl21 but ,126 mg$dl21 SBP $140 mm Hg or DBP $90 mm Hg LDL-C $130 mg$dl21 or HDL-C ,40 mg$dl21

SBP $120 mm Hg or DBP $80 mm Hg but ,90 mm Hg SBP $200 mm Hg or DBP $120 mm Hg Horizontal ST segment depression $2 mm 80 ms . J point Age specific (ml$kg21$min21) (48)

Number (%) . Mean (SD) values RF threshold of RF . threshold 25 (50) 1 (2) 0 (0)

49 (3) 1 (—) 0 (—)

22 (44)

2.2/23.6† (0.5/3.2)

12 (24)

32 (2)

19 5 17 6 10 17

(38) (10) (34) (18) (30) (51)

103 162/98 (31/2) 151/36† (21/12)

18 (36)

128/82 (5/3)

7 (14)

224/105 (22/7)

1 (2) 9 (20)

2.4 (—) 30.5 (4)

*RF = risk factor; M = men; W = women; LDL-C = low-density lipoprotein cholesterol; HDL-C = high-density lipoprotein cholesterol; BMI = body mass index; FBG = fasting blood. †Values represent days per minute.

DISCUSSION The principal finding reported in this study is that despite continuing efforts to improve firefighter fitness through fire service organization standards and recommendations, a contemporary group of professional firefighters in the Southern California exhibited anthropometric, physical fitness, and CVD risk profiles similar to those reported over the past 30 years (8–11,16,22,26,27,34–37,47). Aerobic capacity, V_ O2max, was slightly below average compared with age- and sex-matched reference values but about 10% higher than the weighted average for V_ O2max in previous reports of firefighter fitness (Table 1). Research data suggest that for safety and optimal job performance, firefighters should develop and maintain levels of aerobic capacity equivalent to about 42 ml$kg21$min21 (30,44). The mean V_ O2max for the individuals in the current sample who were below this recommendation was 34 ml$kg21$min21. An average improvement of about 18% would provide the needed increase to meet the recommended standard for these firefighters. Improvement of this magnitude is attainable through systematic exercise training, weight loss, and improved body

composition (37). The low aerobic capacity relative to recommendations for firefighters observed in the present sample is consistent with several other reports and the widely acknowledged belief that the level of aerobic fitness in firefighters is often insufficient to safely and effectively meet the physiological demands of the intense work rates placed on them. A number of factors can be implicated as contributory to suboptimal performance and cardiovascular events among firefighters. Chief among these is overexertion (12) that leads to earlier fatigue during performance of high demand work tasks. Overexertion increases cardiovascular strain and possibly provides a trigger for a sudden cardiac event, especially in individuals with underlying cardiovascular risk factors and unrecognized coronary artery or cerebral vascular disease (2,29,53). In addition, low fitness leading to overexertion vis-a-vis the high work demands may also jeopardize public safety, safety of colleagues, and completion of the mission. Few studies have examined the lactate threshold, V_ O2u, in the context of firefighter fitness. However, this parameter of aerobic fitness has specific relevance to the sustained high VOLUME 28 | NUMBER 3 | MARCH 2014 |

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Firefighter Health and Fitness energy demands required by firefighters. The lactate threshold identifies a level of work that can be sustained for long periods of time without an accumulation of lactic acid thus prolongs the onset of fatigue. Individuals who possess a high V_ O2u are able to sustain higher work rates for longer periods of time. Several studies have suggested that simulated fire suppression tasks require a mean V_ O2 between 29 and 44 ml$kg21$min21 (10). Individuals with V_ O2u near or above this level would be more able to meet these challenges and sustain the work effort while protecting against overexertion. In this study, V_ O2u averaged 23 ml$kg21$min21. This is lower than the 29 ml$kg21$min21 reported in 40 firefighters by Malley et al. (26). However, their subjects also exhibited mean V_ O2max scores of 47 ml$kg21$min21, which were 17% higher than the current subjects. Evidence suggests that exercise training at appropriate intensities typically results in improvements from baseline that are greater than the improvement in V_ O2max (3). This has practical implications for sustaining high demand work performance. One objective of endurance exercise training should include strategies to improve V_ O2u. Obesity brings significant consequences to firefighters, including increased numbers of cardiovascular risk factors (41), higher likelihood of ECG abnormalities (42), and increased risk for job disability (40). Furthermore, a recent study by Fahs et al. (11) demonstrated that obese firefighters have signs of vascular dysfunction compared with lean firefighters, which may predispose to cardiovascular events. Mean BMI in this study was 27.5 kg$m22, and the average BMI previously reported in firefighters was 28 kg$m22 (Table 1). In other words, data from this study show little difference in the average BMI compared with previous reports of firefighter fitness and continue to suggest that the average firefighter is OW. In the current cohort, 22% were obese (BMI .30 kg$m22) and, on the basis of reference values for percent body fat (48), 33% of our sample would have been classified as having above average or well above average fatness for age and sex (48). Athletes, particularly those who move their body weight through space, tend to have lower percentage fat (e.g., 5–15%) to optimize performance. Given that firefighters should be considered as professional occupational athletes, with the possibility of exposure to thermal stress that may be exacerbated by excess body fat, target body fat values in firefighters should be lower than average. A target of #18% body fat would seem reasonable. Muscle strength and local muscle endurance were determined in this study by handgrip strength, abdominal endurance, push-ups, and “core” endurance tests. Grip strength scores for subjects in this study were similar to those previously reported for firefighters and were about 7% higher than age-/sex-matched healthy individuals. The utility of grip strength to indicate general body strength is limited (r2 = 0.48) (49), particularly for dynamic muscle actions of the lower extremity. However, isometric grip strength is important for

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firefighters because several of the “essential job tasks” for firefighters require grip strength for tasks that include pulling hose, lifting and carrying heavy objects, ventilating roofs or walls, and wielding an axe (30). Muscle endurance scores were similar to previous fitness reports among firefighters but more than twice the upper body endurance (push-ups) for healthy age- and sex-matched reference individuals and 18% greater than abdominal endurance. For the firefighter, elements of muscle performance, core stability, and flexibility are important in effectively carrying out most of the NFPA 1582 essential job tasks (30). These not only include tasks noted above for grip strength but also include lifting and climbing flights of stairs while wearing PPE, carrying and using tools such as an axe or Halligan bar for cutting and forcible entry, cutting and opening up concealed spaces in structures, and extensive crawling. Several studies have revealed moderately strong but significant associations between upper body strength and endurance and grip strength with performance of simulated firefighting tasks (27,36,54). Strong associations between performance time on the Candidate Physical Abilities Test (CPAT) with upper body strength and grip strength were shown in 1 study (38), whereas another showed significant predictive value in CPAT performance by grip strength but not upper or lower body strength measures (52). In both of these studies, however, aerobic and anaerobic performances were the strongest predictors of CPAT performance. Few studies have examined the role of flexibility in performance or prevention of injury from firefighting duties. Hilyer et al. (21), in a study of 469 municipal firefighters, reported that subjects assigned to stretch training increased flexibility and reduced the severity of injury and cost of time lost from work despite no difference in injury incidence when compared with the control group. More than 40 years ago, the relationship between back injuries and measures of fitness, including flexibility, isometric lift strength, and the power output on a cycle ergometer was reported in 1,652 firefighters studied over a 3-year period in Los Angeles (4). Subjects were divided into least fit, mid-fit, and most fit, and the incidence of back injuries was 7.1, 3.2, and 0.8%, for these groups, respectively. Taken together, the data from muscle strength, endurance, and flexibility assessments in this study confirm previous observations in firefighters and also suggest that a significant need exists to increase performance in these areas to meet the significant work demands of the firefighter. Over recent years, sudden cardiac death has accounted for 40–51% of annual firefighter fatalities (12) and is the leading cause of line-of-duty death in this occupation (23). Strenuous physical activity, especially if it is unaccustomed, can result in sudden cardiac events in individuals with underlying CVD (2). Analyses of fatalities in the fire service revealed that firefighters are 10–100 times more likely to suffer such an event after fire suppression activities than during routine station work (23,24). Recently, Soteriades et al. (42) reviewed

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Journal of Strength and Conditioning Research the cardiovascular demands of firefighting and the cardiovascular risk factors among fire service personal and proposed a mechanistic model to explain how the strenuous duties of firefighting may serve as a trigger for cardiovascular events. These data reinforce the need to identify and reduce known CVD risk factors among firefighters and increase exercise and physical activity. As reviewed in Table 3, more than half the firefighters in this study had 3 or more conventional cardiovascular risk factors. Of these, age was a risk factor in half the subjects. Although age is a nonmodifiable risk factor, men older than 45 years should give special attention to the reduction of those risk factors that are modifiable. Indeed, Fahy et al. (12) recently reported that 83% of the sudden cardiac deaths reported in 2010 were in firefighters older than 45 years. No one smoked in the current cohort, but 44% of the firefighters did not meet threshold values for physical activity, 24% were obese, 57% met criteria for prediabetes, and 50% were prehypertensive or hypertensive at rest. Previous reports in firefighters do suggest trends toward prehypertension (Table 1), OW or obesity, high relative body fat, low aerobic fitness, and low HDL-C levels. Twenty percent of the current cohort had aerobic capacity, V_ O2max, values below the 20th percentile for age, with a mean value for these participants of 30 ml$kg21$min21. The mean age_ O2max values for the 13 previously published and sex-specific V firefighter fitness studies (Table 1) suggest a 20th percentile _ O2max in our subjects (48). These data suggest ranking for V an urgent need to intervene with risk reduction interventions for all firefighter personnel. Several approaches are available to reduce line-of-duty deaths from cardiovascular events. These include early identification of risk and systematic approaches to mitigate this risk that include well designed and systematic exercise training. Future studies could also examine the feasibility of physiological monitoring during performance of arduous firefighting tasks and monitoring physiological responses to exercise training and performance of firefighting drills. Given that the PHASER critical review of literature surrounding risks inherent with firefighting revealed lack of physical fitness and the presence of cardiovascular risk factors as major contributors to cardiovascular events in firefighters, it is clear that a relatively easy, low cost, and potentially very effective approach for risk reduction would include preventative strategies involving risk screening and exercise training. It is well known that when regularly performed, specific types of exercise training are effective in improving health-related fitness and in reducing CVD risk factors. Fire service organizations have developed guidelines to improve firefighter health and reduce risk of death and injuries in the fire service. However, even though a recent NFPA report (33) continued to emphasize the need for health and wellness programs, it also reported that 70% of fire departments still have no such program. Data from this study and those from previous investigations clearly indicate

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a need that is not being adequately met. Fitness professionals could play a pivotal role in implementing fire service specific guidelines along with innovative training methods and risk reduction strategies. Indeed, the WFI has suggested that a professional exercise specialist with a degree in exercise science or related field plus thorough knowledge of the job of firefighting should be part of a broad-based department fitness committee that includes labor, management, and the fire department physician(s) (14). This study has some limitations. Our sample size was limited to a relatively small municipal fire department with only 51 ERs who may not have been representative of all firefighters across the United States. However, this department was similar to 70% of fire departments across the United States that have no formal wellness or fitness program. It is possible that members of fire departments with wellness or fitness programs have lower CVD risk than those reported here and in previous studies.

PRACTICAL APPLICATIONS Fire service leaders, researchers, and clinicians agree that firefighters require high levels of aerobic and musculoskeletal fitness and appropriate body weight and composition to safely and effectively meet the heavy work demands of firefighting. Failure to do so creates a mismatch between ability and demand, which may result in triggering cardio- or cerebrovascular events. We have provided historical and contemporary evidence that firefighters often lack appropriate fitness levels and have worrisome risk profiles for CVD. Despite well-formulated recommendations for health and fitness development in the form of firefighter medical and fitness standards (NFPA 1582 and 1583) and the guidelines set forth in the WFI, recommended programs are not being implemented in many departments. These problems are not insurmountable, but strategies are needed to help fitness professionals become engaged with local fire departments and national firefighter leadership to more effectively implement health and fitness programs for firefighters. Hence, the practical application of this report is in the form of a call to action to fitness professionals. We strongly encourage qualified personal trainers to take initiative for active engagement in promoting firefighter health, fitness, and performance. Initially, this might be through increased involvement with specialty groups such as the National Strength and Conditioning Association’s (NSCA) Tactical Strength and Conditioning Program, the American College of Sports Medicine’s (ACSM) Environmental and Occupational Physiology or Strength & Conditioning Specialties interest groups. Second, personal trainers who understand the demands of firefighting and the application of fitness training and risk reduction might offer their expertise both through direct involvement with individual fire departments and through their professional organizations. This report provides a ready reference for fitness professionals with historical background, contemporary data, a clear VOLUME 28 | NUMBER 3 | MARCH 2014 |

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Firefighter Health and Fitness indication of need, and existing fire service resources for implementing wellness and fitness programs for firefighters. These data may be used for strategizing initial presentations to fire department command personnel, unions, and city risk managers with the objective of establishing a formal wellness/fitness program. Presently, there is no formal collaboration between fitness organizations, such as the NSCA or ACSM, and the fire service. We strongly recommend development of such collaboration. One outcome could be creation of registry of qualified personal trainers that could be accessed by local fire departments. At the organizational level, meaningful collaborations can lead to improved program content and structure. There is precedence for fitness organization-fire service collaboration as seen in the Peer Fitness Trainer certification program jointly administered by the American Council on Exercise and the NFPA. However, this certification is specific to firefighters (peers) who may not have the level of formal education, certification, and experience necessary to effect and manage fitness/wellness programs. Indeed, the WFI recommends that Peer Fitness Trainers should work under the direction of a professional exercise specialist with a degree in exercise science or related field and fire department physician(s) (14). There is an urgent need to take aggressive steps forward in reducing risk of line-of-duty deaths in firefighters. Exercise training and risk reduction programs are obvious candidates for achieving this objective. Expert guidance in implementing these programs is needed but too often there is not sufficient interaction between fitness professionals and local fire departments. Hence, we issue a call to action for active engagement of qualified fitness trainers, professional organizations, and formation of collaborations with fire service groups to effect fitness and risk reduction programs.

ACKNOWLEDGMENTS We acknowledge the support provided by the Department of Homeland Security Science and Technology Directorate (Jalal Mapar, Program Manager) for this study. In addition, we are indebted to Bruce H. Varner, Retired Fire Chief, Santa Rosa Fire Department, CA for his advice and consultation. This work was supported by the Department of Homeland Security—Science and Technology Directorate, Jalal Mapar, Program Manager, Contract HSHQDC-10-C-00089:P00001.

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Ebola: a call to action.

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