Extreme sacrifice: sudden cardiac death in the US Fire Service

The dietary inflammatory index and cardiometabolic parameters in US firefighters

Introduction

Dietary choices play a crucial role in influencing systemic inflammation and the eventual development of cardiovascular diseases (CVD). The Dietary Inflammatory Index (DII®) is a novel tool designed to assess the inflammatory potential of one's diet. Firefighting, which is characterized by high-stress environments and elevated CVD risk, represents an interesting context for exploring the dietary inflammatory-CVD connection.

Aim

This study aims to investigate the associations between Energy-adjusted Dietary Inflammatory Index (E-DII™) scores and cardiometabolic risk parameters among US firefighters.

Methods

The study analyzed 413 participants from the Indianapolis Fire Department who took part in a Federal Emergency Management Agency (FEMA)-sponsored Mediterranean diet intervention trial. Thorough medical evaluations, encompassing physical examinations, standard laboratory tests, resting electrocardiograms, and submaximal treadmill exercise testing, were carried out. Participants also completed a detailed food frequency questionnaire to evaluate dietary patterns, and E-DII scores were subsequently computed based on the gathered information.

Results

Participants had a mean body mass index (BMI) of 30.0 ± 4.5 kg/m2 and an average body fat percentage of 28.1 ± 6.6%. Regression analyses, adjusted for sex, BMI, maximal oxygen consumption (VO2 max), max metabolic equivalents (METS), age, and body fat percentage, revealed significant associations between high vs. low E-DII scores and total cholesterol (β = 10.37, p = 0.04). When comparing low Vs median E-DII scores there is an increase in glucose (β = 0.91, p = 0.72) and total cholesterol (β = 5.51, p = 0.26).

Conclusion

Our findings support an association between higher E-DII scores and increasing adiposity, as well as worse lipid profiles.

Physiological Stress Responses to a Live-Fire Training Evolution in Career Structural Firefighters

OBJECTIVE

This study assessed firefighters' physiological stress response to a live fire training evolution (LFTE).

METHODS

Seventy-six ( n = 76) firefighters completed an LFTE. Salivary samples were collected pre-, immediately post, and 30-min post-LFTE and analyzed for α-amylase (AA), cortisol (CORT), and secretory immunoglobulin-A (SIgA).

RESULTS

Concentrations of AA, CORT, and SIgA were elevated immediately post LFTE versus pre (P<0.001) and 30-min post (P<0.001). Cohen's d effect size comparing pre and immediately-post means were 0.83, 0.77, and 0.61 for AA, CORT, and SIgA and were 0.54, 0.44, and 0.69 for AA, CORT, and SIgA, comparing immediately-post and 30-min post, respectively.

CONCLUSIONS

These data demonstrate the stress response and activation of the hypothalamic-pituitary-adrenal/sympathetic-adreno-medullar axis and immune system immediately after real-world firefighting operations. Future work is needed to understand the impact of elevated stress biomarkers on firefighter performance and disease risk.

Relationship between Simulated Fire Suppression Activities and Acute Cardiac and Respiratory Events in Firefighters

Cardiac deaths account for the largest share of on-duty firefighter deaths. To help ensure duty fitness and minimize injury risk, many fire departments require the passing of an annual physical ability test, consisting of a battery of simulated fire suppression activities (sFSAs). The purpose of the study was to determine the relationship of sFSA performance to acute cardiac and respiratory events (ACREs) and the effect that estimated VO2max has on sFSA performance. The study was retrospective. As part of an annual physical ability test, five timed sFSAs were performed, summed for a composite time, and categorized into three performance levels (fast, moderate, and slow). Estimated VO2max was determined using the Forestry Step Test. A significant (p = 0.023) linear trend was observed with higher sFSA performance times being associated with a higher proportion of firefighters going on to suffer an ACRE. The estimated VO2max was significantly (p < 0.001) higher in the fast group compared to the slow group. There was not a significant (p = 0.70) difference in estimated VO2max between the moderate and slow groups. Estimated VO2max performance and sFSA performance were significantly correlated, with rs(488) = -0.272 and p < 0.001. Poorer sFSA performance was found to be associated with a higher proportion of ACREs. The results suggest that sFSA performance may be a valid indicator of ACRE injury risk and aerobic capacity.

Structural and functional cardiac parameters across occupations: a cross-sectional study in differing work environments

Previous investigations have highlighted notable variations in cardiovascular risk indicators associated with various professional categories. However, only a few studies have examined structural and functional cardiac parameters using echocardiography within distinct occupational groups. Hence, this study endeavored to assess cardiac structural and functional parameters in three additional occupations: firefighters (FFs), police officers (POs), and office workers (OWs). This prospective study encompassed 197 male participants (97 FFs, 54 POs, and 46 OWs) from Germany. All participants underwent 2D and Doppler echocardiography in resting conditions; standard parasternal and apical axis views were employed to evaluate structural (diastolic and systolic) and functional (systolic and diastolic function, and strain) cardiac parameters. All three occupational groups exhibited a tendency towards septal hypertrophy. Notably, OWs exhibited the largest diastolic interventricular septum diameter (IVSd), at 1.33 ± 0.25 cm. IVSd significantly varied between POs and OWs (p = 0.000) and between POs and FFs (p = 0.025). Additionally, during diastole a substantially larger left ventricular posterior wall diameter (LVPWd) was observed in OWs compared to FFs (p = 0.001) and POs (p = 0.013). The left ventricular diastolic cavity diameter (LVIDd) and the left ventricular systolic cavity diameter (LVIDs) were significantly higher in POs than they were in FFs (LVIDd: p = 0.001; LVIDs: p = 0.009), and the LVIDd was notably higher in FFs (p = 0.015) and POs compared to OWs (p = 0.000). FFs exhibited significantly better diastolic function, indicated by higher diastolic peak velocity ratios (MV E/A ratio) and E/E' ratios, compared to POs (E/A ratio: p = 0.025; E/E' ratio: p = 0.014). No significant difference in diastolic performance was found between OWs and FFs. Significantly higher E'(lateral) values were noted in POs compared to FFs (p = 0.003) and OWs (p = 0.004). Ejection fraction did not significantly differ among FFs, POs, and OWs (p > 0.6). The left ventricular mass (LV Mass) was notably higher in POs than it was in FFs (p = 0.039) and OWs (p = 0.033). Strain parameter differences were notably improved in two- (p = 0.006) and four-chamber (p = 0.018) views for FFs compared to POs. Concentric remodeling was the predominant change observed in all three occupational groups. Significant differences in the presence of various forms of hypertrophy were observed in FFs, POs, and OWs (exact Fisher test p-values: FFs vs. OWs = 0.021, POs vs. OWs = 0.002). OWs demonstrated notably higher rates of concentric remodeling than FFs did (71.77% vs. 47.9%). This study underscores disparities in both functional and structural parameters in diverse occupational groups. Larger prospective studies are warranted to investigate and delineate differences in structural and functional cardiac parameters across occupational groups, and to discern their associated effects and risks on the cardiovascular health of these distinct professional cohorts.

Expanding Research on Firefighter Trainee Fitness, Reasons for Academy Release, and the Predictive Capabilities of Fitness Tests

ABSTRACT

Lockie, RG, Orr, RM, Montes, F, and Dawes, JJ. Expanding research on firefighter trainee fitness, reasons for academy release, and the predictive capabilities of fitness tests. J Strength Cond Res 38(4): 724-733, 2024-Firefighter trainees need a level of fitness to be admitted to and complete a training academy. Fitness could indicate a trainee's likelihood of graduation, in addition to their reasons for release. This study determined fitness differences between firefighter trainees who graduated (GRAD) from academy or were released because of injury (RELI), performance test failures (RELP), or resignation (RELR), and whether fitness predicted graduation. Occupational physical ability test (OPAT) data for 686 trainees were analyzed, including: Illinois agility test; push-ups; pull-ups; leg tucks; maximal aerobic capacity (V̇O2max); backward overhead medicine ball throw; 10-repetition maximum deadlift; and farmer's carry. Raw and scaled (based on internal scoring) scores were recorded. Trainees were split into GRAD (n = 576), RELI (n = 33), RELP (n = 66), and RELR (n = 11) groups. A 1-way ANOVA with Bonferroni post hoc calculated between-group differences. Stepwise linear regression determined whether fitness predicted group inclusion. Receiver operating curves and area under the curve (AUC) derived test accuracy for predicting academy release. The GRAD group was superior (p ≤ 0.04) to the RELI group in all tests except push-ups, pull-ups, and farmer's carry; RELP group in all tests except the farmer's carry; and RELR group in V̇O2max, deadlift, and total OPAT score. Select fitness tests could predict inclusion in each group, although the explained variances were low (∼1-11%). Raw V̇O2max (AUC = 0.71) and total OPAT score (AUC = 0.74) had acceptable prediction accuracy. Fitness influenced academy graduation and reasons for release. Scaled scores could predict group inclusion in this department; V̇O2max and total OPAT score provided the most accurate predictors for release.

Firefighter Health: A Narrative Review of Occupational Threats and Countermeasures

Structural firefighters are responsible for protecting properties and saving lives during emergency operations. Despite efforts to prepare firefighters for these hazardous occupational demands, the unfortunate reality is that the incidence of health morbidities is increasing within the fire service. Specifically, cardiovascular disease, cancer, and mental health disorders are among the most documented morbidities in firefighters. Pubmed and Google Scholar search engines were used to identify peer-reviewed English language manuscripts that evaluated firefighters' occupational health threats, allostatic factors associated with their occurrence, and evidence-based strategies to mitigate their impact. This narrative review provides fire departments, practitioners, and researchers with evidence-based practices to enhance firefighters' health.

Evaluation of the relationship between occupational-specific task performance and measures of physical fitness, cardiovascular and musculoskeletal health in firefighters

INTRODUCTION

Firefighters are required to perform physically strenuous tasks such as hose drags, victim rescues, forcible entries and stair climbs to complete their public safety mission. Occupational-specific tasks are often used to evaluate the ability of firefighters to adequately/safely perform their duties. Depending on the regions, occupational-specific tasks include six to eight individual tasks, which emphasize distinct aspects of their physical fitness, while also requiring different levels of cardiovascular (CVH) and musculoskeletal health (MSH). Therefore, the aim of this study was to evaluate the relationship between specific occupational task performance and measures of physical fitness, cardiovascular and musculoskeletal health.

METHODS

Using a cross-sectional design, 282 full-time male and female firefighters were recruited. A researcher-generated questionnaire and physical measures were used to collect data on sociodemographic characteristics, CVH, MSH and weekly physical activity habits. Physical measures were used to collect data on physical fitness and occupational-specific task performance.

RESULTS

Absolute cardiorespiratory fitness (abV̇O2max), grip strength, leg strength, push-ups, sit-ups and lean body mass (all p < 0.001) had an inverse association with completion times on all occupational-specific tasks. Age was positively related to the performance of all tasks (all p < 0.05). Higher heart rate variability (HRV) was associated with better performance on all tasks (all p < 0.05). Bodyfat percentage (BF%) and diastolic blood pressure were positively associated with the step-up task (p < 0.05). Lower back musculoskeletal injury (LoBMSI), musculoskeletal discomfort (MSD), and lower limb MSD were associated with a decreased odds of passing the step-up. Upper body MSIs (UBMSI), LoBMSIs and Lower back MSD were associated with decreased odds of passing the rescue drag.

CONCLUSION

Firefighters that were taller, leaner, stronger and fitter with a more favourable CVH profile, higher HRV and less musculoskeletal discomfort performed best on all occupational-specific tasks.

Influence of Cardiorespiratory Fitness on Cardiac Autonomic Recovery Among Active-Duty Firefighters

Cornell, DJ, Flees, RJ, Shemelya, CM, and Ebersole, KT. Influence of cardiorespiratory fitness on cardiac autonomic recovery among active-duty firefighters. J Strength Cond Res 38(1): 66–73, 2024—It has been suggested that an inability of the autonomic nervous system (ANS) to recover after strenuous events is a potential cause of sudden cardiac death among firefighters. The purpose of this study was to examine the influence of cardiorespiratory fitness (CRF) on the heart rate recovery (HRR) kinetics of firefighters. Thirty-seven male career active-duty firefighters completed both a submaximal step test and a maximal treadmill graded exercise test. A monoexponential curve was fit to postexercise submaximal and maximal HRR data of each subject. Subjects were placed into Low CRF (n = 13) and High CRF (n = 24) groups based on the standard peak aerobic capacity (V̇O2peak) criterion of <42 ml·kg−1·minute−1 and ≥42 ml·kg−1·minute−1, respectively. After controlling for age and body mass index, CRF was significantly (p < 0.05) correlated with the decay rate ( ) and asymptote ( ) after submaximal exercise (r sp = −0.556; r sp = −0.637, respectively), as well as the , , and amplitude ( ) after maximal exercise (r sp = −0.353; r sp = −0.416; r sp = 0.603, respectively). High CRF firefighters demonstrated a significantly faster after both submaximal (p = 0.003) and maximal exercise (p = 0.043), a lower after submaximal exercise (p = 0.002), and a higher after maximal exercise (p = 0.001), than Low CRF firefighters. Greater CRF was associated with enhanced HRR kinetics after submaximal and maximal exertion, suggesting that CRF may positively influence the ANS recovery of firefighters.

The effect of mild to moderate COVID-19 infection on the cardiorespiratory fitness of firefighters

Introduction

An adequate level of cardiorespiratory fitness (CRF) is critical for firefighters to perform the strenuous and physiologically demanding work of firefighting safely and effectively. The coronavirus disease 2019 (COVID-19) has been shown to negatively impact CRF in both the acute phase and longer-term following infection. This study aimed to determine changes to the CRF of firefighters pre- to post-mild to moderate COVID-19 infection and to investigate the impact of days past COVID-19 infection on change in CRF.

Methods

CRF measures from cardiopulmonary exercise testing (CPET) at annual occupational health exams that occurred pre-COVID-19 infection in 2019 were obtained for firefighters from seven Arizona fire departments. Measures were compared to CPET evaluations from annual health exams the following year in a cohort of firefighters who self-reported mild to moderate illness following COVID-19 infection between exams.

Results

Among a cohort of 103 firefighters, mean age 40 ± 9 years, CRF [as measured by peak oxygen consumption (VO2)] declined by an average of 2.55 ml·kg-1·min-1 or 7.3% (d = -0.38, p < 0.001) following COVID-19 infection (mean time from COVID-19 infection to CPET was 110 ± 78 days). The number of days past COVID-19 infection showed a small, yet significant, relationship to peak VO2 (r = 0.250, p = 0.011). Estimated marginal effects indicated that when biological sex, age, and BMI are controlled for, predicted peak VO2 returned to pre-COVID-19 values ~300 days after COVID-19 infection.

Conclusion

Peak VO2 (ml·kg-1·min-1) declined 7.3% among firefighters an average of 110 days past reporting mild to moderate COVID-19 infection. This decrease has implications for the operational readiness and safety of firefighters.

The Prevalence of Metabolic Syndrome and Its Components in Firefighters: A Systematic Review and Meta-Analysis

Previous studies consistently report a high prevalence of cardiovascular disease (CVD) risk factors among firefighters. However, the clustering of CVD risk factors, defined as metabolic syndrome (MetSyn), has received little attention by comparison. Therefore, the aim of this study was to estimate the pooled prevalence of MetSyn among firefighters. Using combinations of free text for 'firefighter' and 'metabolic syndrome', databases were searched for eligible studies. Meta-analyses calculated weighted pooled prevalence estimates with 95% confidence intervals (CI) for MetSyn, its components and overweight/obesity. Univariate meta-regression was performed to explore sources of heterogeneity. Of 1440 articles screened, 25 studies were included in the final analysis. The pooled prevalence of MetSyn in 31,309 firefighters was 22.3% (95% CI: 17.7-27.0%). The prevalences of MetSyn components were hypertension: 39.1%; abdominal obesity: 37.9%; hypertriglyceridemia: 30.2%; dyslipidemia: 30.1%; and hyperglycemia: 21.1%. Overweight and obesity prevalence rates in firefighters were 44.1% and 35.6%, respectively. Meta-regression revealed that decreased risk of bias (RoB) score and increased body mass index (BMI) were positively associated with an increase in MetSyn prevalence. Since one in five firefighters may meet the criteria for MetSyn, novel interventions should be explored to both prevent MetSyn and reduce the onset of CVD risk factors.

Performing one or more verification VO2 workload(s) immediately after an incremental to maximal graded exercise test significantly increases the proportion of participants who meet the job-related aerobic fitness standard for structural firefighters

PURPOSE

Graded exercise tests (GXTs) are commonly used to determine the maximal oxygen consumption (VO2max) of firefighter applicants. However, the criteria used to confirm VO2max are inconsistent and have a high inter-subject variability, which can compromise the reliability of the results. To address this, a verification phase (VP) after the GXT has been proposed as a "gold standard" protocol for measuring VO2max.

METHODS

4179 male and 283 female firefighter applicants completed a GXT and a VP to measure their VO2max. VO2peak values measured during the GXT were compared to the VO2 values measured during the VP. The proportion of participants who met the job-related aerobic fitness standard during the GXT was compared to that of those who met the required standard during the VP.

RESULTS

For male and female participants that required the VP to attain their VO2max, the VO2peak values measured during the GXT (47.3 ± 6.0 and 41.6 ± 5.3 mL kg-1 min-1) were, respectively, 10.1% and 10.3% lower than the VO2 values measured during the VP (52.1 ± 6.7 and 45.9 ± 6.4 mL kg-1 min-1), p < 0.001. Furthermore, the proportion of male and female participants who met the job-related aerobic fitness standard significantly increased from the GXT to the VP by 11.6% and 29.9%, respectively, p < 0.001.

CONCLUSION

These results strongly support the use of a VP to confirm VO2max, especially for females, older and overweight individuals. These findings are applicable to other physically demanding public safety occupations and when examining the efficacy of training interventions on VO2max.

Physical fitness, cardiovascular and musculoskeletal health, and occupational performance in firefighters

Introduction

To perform their work efficiently and safely, firefighters should maintain all aspects of physical fitness. Cardiac-related incidents are the leading cause of duty-related deaths in firefighters, and many firefighters have poor musculoskeletal health (MSH) that hinder their occupational performance (OP). Establishing the relationship between physical fitness, cardiovascular health (CVH), MSH and OP may add new insight on the most significant factors influencing OP in firefighters, specifically in the City of Cape Town Fire and Rescue Service (CoCTFS), which had not been studied before. Therefore, the purpose of this study was to investigate whether physical fitness, CVH and MSH were associated with OP in firefighters, in the COCTFRS.

Methods

This cross-sectional study included 283 full-time firefighters aged 20-65 years from Cape Town, South Africa. A researcher-generated questionnaire was used to collect data on sociodemographic characteristics, lifestyle factors and MSH. Physical measures were used to collect information on physical fitness, CVH, and OP [using a physical ability test (PAT)]. Linear and binary logistic regressions, adjusted for age, sex, height and weekly metabolic equivalent minutes (WMETM), multivariate analysis of covariance (MANCOVA), adjusted for age, sex, height and body mass index (BMI) and backward stepwise regressions were used to investigate the associations between the various constructs.

Results

From multivariable analyses, age, lean body mass, body fat percentage (BF%), estimated absolute oxygen consumption (abV̇O2max), grip strength, leg strength, push-ups, sit-ups, WMETM and heart rate variability were associated with PAT completion times (all p < 0.01). The MANCOVA showed a significant difference between performance categories of the PAT based on physical fitness and CVH (both p < 0.001). WMETM, BF%, abV̇O2max, grip strength, leg strength and sit-ups explained the highest proportion (50.5%) of the variation in PAT completion times.

Conclusion

Younger, non-obese, fitter and stronger firefighters, with a better CVH status, performed significantly better and were most likely to pass the PAT in firefighters, in Cape Town, South Africa. Firefighters should maintain high levels of physical fitness and a good level of CVH to ensure a satisfactory level of OP.

Weight Status and Binge Drinking Among Male and Female Florida Firefighters

OBJECTIVE

The aim of the study is to examine the association between weight status and binge drinking among Florida firefighters.

METHODS

Health survey data collected between 2015 and 2019 among Florida firefighters participating in the Annual Cancer Survey were analyzed for weight class (healthy, overweight, obese) and binge-drinking behaviors. Binary logistic regression models were fit and stratified by sex while controlling for sociodemographic and health characteristics.

RESULTS

Among 4002 firefighter participants, 45.1% binge drink, 50.9% are overweight, and 31.3% are obese. Among male firefighters, being overweight (adjusted odds ratio = 1.34; 95% confidence interval = 1.10-1.64) or obese (1.29; 1.04-1.61) was significantly associated with binge drinking compared with healthy weight counterparts. In female firefighters, being obese (2.25; 1.21-4.22) was significantly associated with binge drinking but being overweight was not.

CONCLUSIONS

Being overweight or obese is selectively associated with binge drinking among male and female firefighters.

Association between physical fitness and musculoskeletal health in firefighters

Introduction: Firefighters are often placed in situations that require high levels of physical exertion, leading to significant strain on firefighters' musculoskeletal system, predisposing them to musculoskeletal discomfort (MSD) and/or musculoskeletal injury (MSI). Physical fitness programs are often recommended and justified, in part, to prevent injuries. The aim of this study was to determine the association between physical fitness and musculoskeletal health (MSH) in firefighters. Methods: A total of 308 full-time firefighters took part in the study conducted in Cape Town, South Africa. Physical fitness tests encompassed a non-exercise estimation for cardiorespiratory fitness, grip and leg strength for upper and lower body strength, push-ups and sit-ups for muscular endurance, and sit-and-reach for flexibility. The Nordic Musculoskeletal Questionnaire and Cornell Musculoskeletal Discomfort Questionnaire were used to determine MSIs and MSD, respectively. A p-value <0.05 indicated statistical significance. Results: Every one-unit increase in AbVO2max, push-ups, sit-ups, and sit-and-reach decreased the odds of firefighters reporting MSIs by 5% (p = 0.005), 3% (p = 0.017), 3% (p = 0.006), and 3% (p = 0.034), respectively. Every one repetition increase in push-up capacity increased the odds of firefighters reporting neck, elbow and forearm, wrist and hand, and thigh discomfort by 3% (p = 0.039), 4% (p = 0.031), 5% (p = 0.002), and 5%` (p = 0.007), respectively. Every one repetition increase in sit-up capacity increased the odds of firefighters reporting upper back discomfort and thigh discomfort by 5% (p = 0.045) and 7% (p = 0.013), respectively. Conclusion: Maintenance of physical fitness is likely beneficial in reducing MSIs, which, however, may increase the feeling of MSD in firefighters. In addition, it may be noticed that there is an ideal level of physical fitness that is conducive to the reduction of MSIs and should be studied further.

Association between Cardiovascular Disease Risk Factors and Cardiorespiratory Fitness in Firefighters: A Systematic Review and Meta-Analysis

Approximately 45% of on-duty related mortalities were due to sudden cardiac death, with many of these fatalities related to cardiovascular disease and overexertion, while performing emergency duties. Therefore, the aim of this systematic review was to determine the association between cardiovascular disease risk factors and cardiorespiratory fitness in firefighters. A literature search of PubMed, SCOPUS, Web of Science, Embase, EBSCOHost, and ScienceDirect was conducted; the Rayyan® intelligent systematic review tool was used to screen and select studies for inclusion. The appraisal tool for cross-sectional studies and the Critical Appraisal Skills Programme toolkit were used for methodological assessment of included studies. Data were analyzed using the Review Manager 5.3 and MedCalc® statistical softwares to determine the effects of obesity (Z = 10.29, p < 0.001) and aging (Z = 4.72, p < 0.001) on cardiorespiratory fitness. Furthermore, there was a significant effect for cardiorespiratory fitness level on systolic blood pressure (Z = 5.94, p < 0.001), diastolic blood pressure (Z = 2.45, p < 0.001), total cholesterol levels (Z = 3.80, p < 0.001), low-density lipoprotein cholesterol (Z = 4.44, p < 0.001), triglycerides (Z = 3.76, p < 0.001) and blood glucose concentration (Z = 4.78, p < 0.001). Cardiovascular disease risk factors and cardiorespiratory fitness were significantly and inversely associated in firefighters. Fire service departments should adopt behavioral intervention strategies to maintain optimum cardiovascular disease risk factor profiles and cardiorespiratory fitness among firefighters to ensure their occupational well-being.

Change in heart rate variability during two firefighting work cycles

This study aimed to determine whether the change in heart rate variability from pre to post firefighting is modulated by different work cycles. Thirteen male firefighters underwent two firefighting simulations that comprised two identical 25-min work bouts intercalated by a passive recovery period of either 20 min (T20) or 5 min (T5). The square root of the mean squared differences of successive R-R intervals (RMSSD) and aural temperature were measured at rest before (PRE) and after (POST) firefighting simulations. The decrease in RMSSD was different between firefighting simulations (T20: -10 ± 21.2 ms, T5: -19.9 ± 20.9 ms, interaction, p = 0.02). Post-firefighting aural temperature was greater (p = 0.05) in T5 (37.18 ± 0.53 °C) than in T20 (36.88 ± 0.49 °C). In conclusion, a shorter recovery period of 5 min between firefighting work bouts decreases post-firefighting heart rate variability, possibly attributed to a lower parasympathetic reactivation and a higher absolute value of body temperature.

A Pilot Study on the Relationship between Cardiovascular Health, Musculoskeletal Health, Physical Fitness and Occupational Performance in Firefighters

Firefighters’ face life threatening situations and are frequently exposed to numerous physical, chemical, biological, ergonomic and psychosocial hazards. The purpose of this pilot study was to investigate the feasibility of conducting a large-scale study on cardiovascular and musculoskeletal health, physical fitness and occupational performance of firefighters. We conducted a cross-sectional pilot study by recruiting 36 firefighters. A researcher-generated questionnaire and physical measures were used to collect data on sociodemographic characteristics, cardiovascular and musculoskeletal health, physical fitness and occupational performance using a physical ability test (PAT). We documented a high equipment and intra-assessor reliability (r > 0.9). The potential logistic and/or administrative obstacles in the context of a larger study were discerned. Data were successfully retrieved using available equipment and survey instruments. Hypertension (30.6%) dyslipidaemia (33.3%), obesity (36.1%) and physical inactivity (66.7%) were the most prevalent cardiovascular disease risk factors. A significant difference between genders in total PAT completion time was also seen (p < 0.001). Cardiorespiratory fitness, lean body mass, grip strength and leg strength were significantly associated with occupational performance (p < 0.001). The pilot study supports the larger study feasibility and verified equipment and assessors’ reliability for research. Cardiovascular health, musculoskeletal health and physical fitness may be related to PAT performance.

Effects of Cardiovascular Disease Risk Factors, Musculoskeletal Health, and Physical Fitness on Occupational Performance in Firefighters-A Systematic Review and Meta-Analysis

Background: Firefighting is a strenuous occupation, which necessitates that firefighters stay in good physical condition and maintain adequate cardiovascular and musculoskeletal fitness to perform their duties with minimal health and safety risks. The aim of this review is to determine the effects of cardiovascular disease risk factors, musculoskeletal health, and physical fitness on the occupational performance of firefighters. Methods: PubMed/Medline, SCOPUS, Web of Science, EBSCOHost, and ScienceDirect were searched without time-restriction. The appraisal tool for cross-sectional studies and the Critical Appraisal Skills Programme toolkit were used to conduct the methodological assessment. Data were analyzed using Review Manager 5.3, and MedCalc^® statistical software. Results: Age had a moderate effect on occupational performance (Z = 5.15, p < 0.001), whereas gender had a large effect size on occupational performance (Z = 4.24, p < 0.001). A significant moderate negative correlation was found between cardiorespiratory fitness and occupational performance (R = -0.584, p < 0.001). Significant low negative correlations were found between upper body endurance (R = -0.344, p < 0.001), abdominal endurance (R = -0.308, p < 0.001), grip strength (R = -0.421, p < 0.001), upper body strength (R = -0.318, p < 0.001), and lower body strength (R = -0.216, p = 0.020) and occupational performance. Conclusions: Aged firefighters with poor body composition and lower levels of physical fitness performed worse on all occupational performance tasks.

Cardiovascular Disease Risk Factors, Musculoskeletal Health, Physical Fitness, and Occupational Performance in Firefighters: A Narrative Review

Introduction

Firefighting is a strenuous occupation that requires firefighters to be in peak physical condition. However, many firefighters have risk factors for cardiovascular disease, impaired musculoskeletal health, and are not physically fit for duty, which all negatively impact their occupational performance. Therefore, the aim of this review is to determine the relationship between cardiovascular disease risk factors, musculoskeletal health, physical fitness, and occupational performance in firefighters.

Methods

The electronic databases PubMed, SCOPUS, and Web of Science were searched online via the library portal of the University of the Western Cape. Publications and grey literature between the years 2000 to present were used. In total, 2607 articles were identified; after the removal of duplicates 1188 articles were then screened, and were excluded for not meeting initial screening criteria. The remaining 209 full-text articles were screened based on the inclusion and exclusion criteria, where 163 articles were excluded. Only studies that were quantitative were included. This left 46 articles that were then finally included in the current narrative review.

Results

The current literature indicated that significant relationships existed between cardiovascular risk factors, musculoskeletal health, physical fitness, and occupational performance. The results indicated firefighters who were aged, obese, physically inactive, cigarette smokers, and unfit were at the highest risk for cardiovascular and musculoskeletal health complications, and unsatisfactory occupational performance. Musculoskeletal health complications significantly affected occupational performance and work ability and were related to physical fitness of firefighters. Most cardiovascular risk factors were related to physical fitness, and all physical fitness parameters were related to occupational performance in firefighters.

Conclusion

The overwhelming evidence in the current review established that physical fitness is related to occupational performance. However, the relationship between cardiovascular risk factors and musculoskeletal health in relation to occupational performance is less clear and still understudied. Significant gaps remain in the literature.

Practical guidance for firefighter applicants preparing for cardiorespiratory fitness testing: a secondary analysis of self-reported physical activity levels

Adequate cardiorespiratory fitness is critical for firefighters since an insufficient level of fitness threatens the integrity of their operations and could be dangerous for their lives. In fact, the leading cause of mortality for on-duty firefighters is not injury but sudden cardiac death. Therefore, to mitigate these risks, potential firefighter recruits are often required to perform a graded exercise test to determine their cardiorespiratory fitness as part of the recruitment process. However, there are currently limited data available to prospective firefighters on the amounts and types of exercises needed to be successful in the graded exercise test, commonly known as a V̇O_2max test. Physiological parameters for the current secondary analysis were collected on firefighter applicants who performed the graded exercise test where 72% were successful and 28% were unsuccessful to meet the minimum standard set at 42.5 ml kg^-1 min^-1. Prior to their test, applicants were asked to describe their exercise training routine by indicating the number of minutes per week spent exercising. Activities were then divided into one of two categories: endurance exercise or strength and power exercise training. The total exercise training describes the sum of all activities performed each week. The sum of endurance exercise activities and the sum of strength and power exercise activities were compared between the successful and the unsuccessful groups and results showed that successful applicants had a higher training volume and performed more endurance exercise training as compared to unsuccessful applicants. Therefore, practical recommendations related to exercise training regime are presented for firefighter applicants to embrace as guidance to prepare for their graded exercise test as part of their recruitment process.

Eating Habits among US Firefighters and Association with Cardiometabolic Outcomes

Cardiovascular disease is the leading cause of on-duty mortality among firefighters, with obesity as an important risk factor. However, little is known regarding the dietary patterns which are characteristic in this population and how these patterns relate to cardiometabolic outcomes. The aim of this study was to identify the dietary patterns of US firefighters and examine their association with cardiometabolic outcomes. The participants (n = 413) were from the Indianapolis Fire Department, and were recruited for a Federal Emergency Management Agency (FEMA)-sponsored Mediterranean diet intervention study. All of the participants underwent physical and medical examinations, routine laboratory tests, resting electrocardiograms, and maximal treadmill exercise testing. A comprehensive food frequency questionnaire was administered, and dietary patterns were derived using principal component analysis. The mean body mass index (BMI) was 30.0 ± 4.5 kg/m2 and the percentage of body fat was 28.1 ± 6.6%. Using principal component analysis, two dietary patterns were identified, namely a Mediterranean diet and a Standard American diet. Following the adjustment for gender, BMI, maximal oxygen consumption (VO2 max), max metabolic equivalents (METS), age, and body fat percent, the Mediterranean diet was positively associated with high-density lipoprotein (HDL) cholesterol (β = 1.20, p = 0.036) in linear regression models. The Standard American diet was associated with an increase in low-density lipoprotein (LDL) cholesterol (β = −3.76, p = 0.022). In conclusion, the Mediterranean diet was associated with more favorable cardiometabolic profiles, whereas the Standard American diet had an inverse association. These findings could help in providing adequate nutrition recommendations for US firefighters to improve their health.

Effects of Emergency Duties on Cardiovascular Diseases in Firefighters: A 13-Year Retrospective Cohort Study

OBJECTIVES

This study aimed to examine the effects of firefighters' emergency duties on the incidence of cardiovascular disease (CVD).

METHODS

We used a 13-year follow-up in a nationwide retrospective cohort study. A total of 363,137 employees were recruited. The sex-and age-specific incidence of CVD (hypertension, angina pectoris, and acutemyocardial infarction [AMI]) in firefighters and public officials was estimated.

RESULTS

The overall age-specific sex-based incidence of CVD, except for hypertension, was higher in firefighters than in public officials. The age-stratified hazard ratios for the three types of CVD in male firefighters were also higher. AMI was more common in younger firefighters, whereas angina pectoris and hypertension were common in older firefighters.

CONCLUSIONS

Firefighters' duties are more likely to increase the risk of CVD, and preventive strategies with proven benefits are required.

Association Between Atrial Fibrillation and Occupational Exposure in Firefighters Based on Self-Reported Survey Data

Background Exposure to inhaled smoke, pollutants, volatile organic compounds, and polycyclic aromatic hydrocarbons in the firefighting environment has been associated with detrimental respiratory and cardiovascular effects, making firefighters a unique population with both personal and occupational risk factors for cardiovascular disease. Some of these exposures are also associated with development of atrial fibrillation. We aimed to study the association of atrial fibrillation and occupational exposure in firefighters. Methods and Results A cross-sectional survey was conducted between October 2018 and December 2019. Data were gathered electronically and stored in a secure REDCap database through Louisiana State University Health Shreveport. Firefighters who were members of at least 1 of 5 preselected professional organizations were surveyed via electronic links distributed by the organizations. The survey queried the number of fires fought per year as a measure of occupational exposure, as well as self-reported cardiovascular disease. A total of 10 860 active firefighters completed the survey, of whom 93.5% were men and 95.5% were aged ≤60 years. Firefighters who fought a higher number of fires per year had a significantly higher prevalence of atrial fibrillation (0-5 fires per year 2%, 6-10 fires per year 2.3%, 11-20 fires per year 2.7%, 21-30 fires per year 3%, 31 or more fires per year 4.5%; P<0.001). Multivariable logistic regression showed that a higher number of fires fought per year was associated with an increased risk of atrial fibrillation (odds ratio 1.14 [95% CI, 1.04-1.25]; P=0.006). Conclusions Firefighters may have an increased risk of atrial fibrillation associated with the number of fires they fight per year. Further clinical and translational studies are needed to explore causation and mechanisms.

Relationship between Heat Loss Indexes and Physiological Indicators of Turnout Related Heat Strain in Mild and Hot Environments

A validated physiological manikin method was used to qualify environmentally dependent correlations between firefighter turnout THL (total heat loss) and R_ef (intrinsic evaporative resistance) heat strain indexes and core temperature rise in stressful work conducted in mild (25 °C, 65% RH) and in hot (35 °C, 40% RH; 40 °C, 28% RH) conditions. Five turnout suit constructions representing a wide range of breathability were selected. The observed correlations between measured material heat loss and core temperature showed that the THL heat strain index accurately forecast thermal burden in mild environments (< 25 °C); while the R_ef index provided accurate prediction in hot environments (> 35 °C). They showed that the THL index did not predict heat strain in hot work environments. The findings of this study support incorporating both the R_ef and THL heat strain indexes as dual metrics for characterizing the heat strain performance of turnout clothing fabrics.

Retrospective Longitudinal Evaluation of Male Firefighter's Body Composition and Cardiovascular Health

OBJECTIVE

Describe firefighter body composition and cardiovascular health as a function of age.

METHODS

217 male firefighters with 1922 distinct evaluations over 23-years were included in this retrospective analysis. The firefighters had their height, mass, six-site skin-fold, blood pressure, and resting heart rate measured annually. Linear mixed models were used to analyze the effect of age. Significance was set to P < 0.05.

RESULTS

With each 1-year increase in age, mass (0.42 kg, P < 0.001), body mass index (0.13 kg m-2, P < 0.001), body fat percentage (0.18%, P < 0.001), fat mass (0.25 kg, P < 0.001), and fat free mass (0.15 kg, P < 0.001) increased. Systolic blood pressure (-0.09 mm Hg, P = 0.263), diastolic blood pressure (0.05 mm Hg, P = 0.308), and resting heart rate (0.07 beats min-1, P = 0.291) did not change.

CONCLUSIONS

Interventions to maintain healthy body composition are critical to reduce sudden cardiovascular related death risk.

Airborne contamination during post-fire investigations: Hot, warm and cold scenes

Fire investigators may be occupationally exposed to many of the same compounds as the more widely studied fire suppression members of the fire service but are often tasked with working in a given exposure for longer periods ranging from hours to multiple days and may do so with limited personal protective equipment. In this study, we characterize the area air concentrations of contaminants during post-fire investigation of controlled residential fires with furnishings common to current bedroom, kitchen and living room fires in the United States. Area air sampling was conducted during different investigation phases including when investigations might be conducted immediately after fire suppression and extended out to 5 days after the fire. Airborne particulate over a wide range of dimensions, including sub-micron particles, were elevated to potentially unhealthy levels (based on air quality index) when averaged over a 60 min investigation period shortly after fire suppression with median PM2.5 levels over 100 µg/m³ (range 16-498 µg/m³) and median peak transient concentrations of 1,090 µg/m³ (range 200-23,700 µg/m³) during drywall removal or shoveling activities. Additionally, airborne aldehyde concentrations were elevated compared to volatile organic compounds with peak values of formaldehyde exceeding NIOSH ceiling limits during the earliest investigation periods (median 356 µg/m³, range: 140-775 µg/m³) and occasionally 1 day post-fire when the structure was boarded up before subsequent investigation activities. These results highlight the need to protect investigators' airways from particulates when fire investigation activities are conducted as well as during post-fire reconstruction activities. Additionally, vapor protection from formaldehyde should be strongly considered at least through investigations occurring 3 days after the fire and personal formaldehyde air monitoring is recommended during investigations.

Effect of live-fire training on ventricular-vascular coupling

INTRODUCTION

Cardiovascular events are a leading cause of firefighter duty-related death, with the greatest risk occurring during or shortly after fire suppression activity. Increased cardiovascular risk potentially manifests from detrimental changes in ventricular function, vascular load, and their interaction, described as ventricular-vascular coupling.

PURPOSE

To determine the effect of live-fire training on ventricular-vascular coupling.

METHODS

Sixty-eight male (28 [Formula: see text] 7 years, 26.9 [Formula: see text] 3.9 kg/m²) and fifteen female (36 [Formula: see text] 8 years, 24.3 [Formula: see text] 3.9 kg/m²) firefighters completed hemodynamic and cardiac measures before and after 3 h of intermittent live-fire training. Left ventricular function was assessed as ejection fraction (EF) and ventricular elastance (E_LV: end systolic pressure [ESP]/end systolic volume) via echocardiography and applanation tonometry-estimated ESP. Vascular load was assessed as arterial elastance (E_A: ESP/stroke volume [SV]). Ventricular-vascular coupling (VVC) was quantified as the ratio of E_A to E_LV and indexed to body surface area (E_AI, E_LVI).

RESULTS

Following firefighting EF decreased (p < 0.01) with no change in E_LVI (p = 0.34). SV decreased (p < 0.01) with no change in ESP (p = 0.09), driving a significant increase in E_AI (p < 0.01). These changes resulted in a significant increase in the VVC ratio (p < 0.01).

CONCLUSION

The findings suggest that firefighting does not alter ventricular elastance but increases arterial elastance in healthy firefighters, resulting in a mismatch between ventricular and vascular systems. This increase in ventricular-vascular coupling ratio and concomitant reduction in ventricular systolic function may contribute to increased cardiovascular risk following live firefighting.

Advanced Functional Materials for Intelligent Thermoregulation in Personal Protective Equipment

The exposure to extreme temperatures in workplaces involves physical hazards for workers. A poorly acclimated worker may have lower performance and vigilance and therefore may be more exposed to accidents and injuries. Due to the incompatibility of the existing standards implemented in some workplaces and the lack of thermoregulation in many types of protective equipment that are commonly fabricated using various types of polymeric materials, thermal stress remains one of the most frequent physical hazards in many work sectors. However, many of these problems can be overcome with the use of smart textile technologies that enable intelligent thermoregulation in personal protective equipment. Being based on conductive and functional polymeric materials, smart textiles can detect many external stimuli and react to them. Interconnected sensors and actuators that interact and react to existing risks can provide the wearer with increased safety, protection, and comfort. Thus, the skills of smart protective equipment can contribute to the reduction of errors and the number and severity of accidents in the workplace and thus promote improved performance, efficiency, and productivity. This review provides an overview and opinions of authors on the current state of knowledge on these types of technologies by reviewing and discussing the state of the art of commercially available systems and the advances made in previous research works.

The combination of deep breathing and mental imagery promotes cardiovascular recovery in firefighters

Firefighters' rescue operations involve intense physical activity associated with a high level of cardiovascular stress. To sustain such intense physical performance whilst maintaining a healthy heart, it is crucial that they benefit from rapid recovery between each intervention. This study aimed at investigating the impacts of a recovery protocol combining deep breathing and mental imagery. Forty firefighters were divided into two experimental groups which undertook two maximum fitness tests separated by either the control recovery protocol (30 min reading time; n = 20) or the experimental recovery protocol (30 min of deep breathing and mental imagery; n = 20). When compared to the pre-tests, the percentage evolution ratios in the post-tests for the Cooper performance, the heart rate recovery and the parasympathetic reactivation were promoted by the experimental protocol, compared to simple reading. In light of these results, we propose the use of practices of deep-breathing combined with mental imagery to improve firefighters' recovery. Practitioner summary: Firefighters' activities involve intense physical activities associated with a high level of psychological stress. Enhancing their recovery after each rescue intervention appears crucial. The results of this study showed that a recovery protocol combining deep breathing and mental imagery promotes heart rate recovery and better maintenance of physical fitness.

A Mediterranean Lifestyle Is Associated With Lower Hypertension Prevalence and Better Aerobic Capacity Among New England Firefighter Recruits

OBJECTIVE

Examine the association between healthy Mediterranean lifestyle practices and cardiovascular disease (CVD) risk factors among New England firefighter recruits.

METHODS

A MEDI-Lifestyle score was used to measure adherence to a Mediterranean lifestyle (not smoking, increased physical activity, high adherence to Mediterranean diet, non-obese body mass index, decreased screen time, adequate nightly sleep, and napping) among the recruits. MEDI-Lifestyle scores were cross-sectionally analyzed with blood pressure, aerobic capacity, and other CVD risk factors.

RESULTS

Among 92 recruits, high adherence to MEDI-Lifestyle was significantly associated with a decreased risk of prevalent hypertension (odds ratio [OR] = 0.14 [0.03-0.71]) and a greater probability of high aerobic capacity (OR = 5.80 [1.05-32.05]) as compared with low adherence in age- and sex-adjusted analyses.

CONCLUSIONS

Increased adherence to MEDI-Lifestyle is associated with a better CVD risk profile in firefighter recruits.

Relationship Between Various Coronary Artery Disease Risk Factors in Firefighters

OBJECTIVE

To determine the correlation between the various coronary artery disease risk factors in firefighters.

METHODS

The study used a quantitative, cross-sectional, and correlational study design. A total of 124 full-time firefighters were conveniently recruited to participate. Research procedures were based on the ACSM guidelines.

RESULTS

Significances were found between age and body mass index (BMI) (r = 0.42, P < 0.001), age and waist circumference (WC) (r = 0.52, P < 0.001), BMI and WC (r = 0.88, P < 0.001), BMI and diastolic blood pressure (DBP) (r = 0.48, P < 0.001), between WC and DBP (r = 0.48, P < 0.001) and between gender and cigarette smoking (χ2[1] = 5.66, P = 0.017).

CONCLUSION

There were significant strong relationships between BMI, SBP, DBP, dyslipidemia, and increasing age, especially in male firefighters. Reducing key risk factors should be emphasized.

Changes in Firefighter Weight and Cardiovascular Disease Risk Factors over Five Years

Purpose

This study aimed to assess changes in cardiovascular disease (CVD) risk factors in firefighters who lost, maintained, or gained weight over 5 yr.

Methods

Anthropometrics and biomarkers of CVD were measured during two occupational medical exams 4.8 yr apart in 656 career firefighters. Weight change subgroups were loss (decrease of >3% body weight), stable (within ±3% body weight), and gain (increase of >3% body weight). Changes in CVD risk factors in the total sample and within weight change subgroups were tested for statistical significance using paired t-tests.

Results

After 5 yr, 12% of the sample lost weight, 38% maintained weight, and 50% gained weight. Firefighters on average had significant increases (P < 0.001) in body weight (2.5 ± 0.2 kg), body mass index (0.8 ± 0.1 kg·m⁻²), total cholesterol (5.5 ± 1.4 mg·dL⁻¹), LDL cholesterol (5.2 ± 1.2 mg·dL⁻¹), and blood glucose (2.1 ± 0.5 mg·dL⁻¹). Firefighters who gained weight (6.6 ± 0.2 kg) had significant increases (P < 0.001) in total cholesterol (12.9 ± 1.8 mg·dL⁻¹), LDL cholesterol (11.1 ± 1.6 mg·dL⁻¹), and blood glucose (2.9 ± 0.7 mg·dL⁻¹) with a significant decrease (P ≤ 0.01) in HDL cholesterol (−1.3 ± 0.4 mg·dL⁻¹). Firefighters who lost weight (−7.2 ± 0.5 kg) had significant decreases (P < 0.05) in total cholesterol (−8.5 ± 3.9 mg·dL⁻¹), LDL cholesterol (−6.7 ± 3.3 mg·dL⁻¹), and blood pressure (systolic: −5.3 ± 1.3 mm Hg; diastolic −4.2 ± 1.0 mm Hg) with a significant increase (P < 0.05) in HDL cholesterol (2.3 ± 1.0 mg·dL⁻¹).

Conclusions

Although improvements in cardiovascular health among firefighters who lost weight were found, 50% of the sample gained weight with adverse changes in measures of cardiovascular health. Given that sudden cardiac death is the most common cause of duty-related death among firefighters, with increased risk among obese firefighters, the amount of weight gain and the adverse changes in cardiovascular health suggest the need for improvements in health promotion programs for firefighters in the United States.

Barriers to Weight Management Among Overweight and Obese Firefighters

OBJECTIVE

To examine barriers to weight management among firefighters.

METHODS

Health risk data collected on 2373 overweight firefighters were used for this cross-sectional study. Barriers to weight management were the dependent variables and demographic characteristics, readiness for change, and health risk factors were the correlates in the multivariate-adjusted logistic models.

RESULTS

Overweight firefighters who were ready to begin a weight management program were more likely to identify "lack of knowledge about weight management," "lack of access to exercise opportunities," and "eating helps me cope with stress" and report a greater number of barriers toward weight management. Older firefighters were less likely to identify or report one or more barriers to weight management.

CONCLUSION

Understanding barriers, readiness for change, and age may be useful in planning interventions to help firefighters better manage their weight.

The Effects of Fire Academy Training and Probationary Firefighter Status on Select Basic Health and Fitness Measurements

PURPOSE

This study aimed to investigate changes in firefighter recruits' select health and fitness measurements, from academy training to the early probationary firefighter period.

METHODS

Firefighter recruits from two New England fire academies were followed up prospectively from enrollment at the academy to graduation after 15- to 16-wk training programs, and then for an average of 8 months as probationary firefighters. The participants' demographic, lifestyle, and mental health information was collected using a questionnaire. Body mass index, percent body fat, blood pressure, and push-ups were also measured at each time point. Furthermore, the academies tested the recruits on selected fitness measures (push-ups, pull-ups, and 1.5-mile running time) at academy entry, midtraining, and at graduation.

RESULTS

Ninety-two recruits consented and were included in the analyses. The recruits' percent body fat significantly decreased (median, 21.0%-18.2%) from baseline to graduation, and push-up capacity significantly improved (median, 34-53 per minute) in the same period, along with pull-ups and 1.5-mile running time. However, the recruits' blood pressure, both systolic and diastolic, increased significantly by an average of 3 mm Hg during the training. Those completing probationary follow-up (45/92 recruits) showed that most health/fitness improvements declined after graduation. From academy graduation to probationary follow-up, recruits' physical activity decreased and TV screen time increased significantly, leading to a lower healthy lifestyle score (median, 4-3). After multivariate adjustments, the recruits' diastolic blood pressure increased by 2 mm Hg per measuring time throughout the study period.

CONCLUSIONS

Fire academy training improved recruits' select health and fitness measurements, but the benefits dissipated as probationary firefighters, and blood pressures increased throughout the study period. Further interventions regarding blood pressure and to maintain training benefits after joining fire departments are warranted.

Evaluation of Functionality of Warning System in Smart Protective Clothing for Firefighters

Recent achievements in the field of miniaturization of electronics have led to a significant interest in its application into the protective clothing for firefighters in order to improve their safety and health. However, up to now there are not any requirements and standardized test methods enabling confirmation of safety of use and functionality of these systems in work environment. In the paper, an importance of evaluation of such smart wearable system in predicted utility conditions is highlighted. Three variants of the specially developed personal warning systems (PWSs) for integration with either health status or environmental sensors to be used in smart protective clothing for firefighters are presented, i.e., with LCD display, LED diodes and vibrating element. For the purpose of evaluation a new testing methodology was developed. The PWSs were evaluated on a basis of perception of warning signals by firefighters in simulated utility conditions including temperature, light, noise, fog and performed activities. In the case of marching, even 75% of signals generated by PWS with LCD display were not received. Physical activity did not influence on functionality of PWS with vibrating element. For the PWS with LED diodes, the signal was received statistically significantly quicker than in the case of other PWS and the mean value of voice response time was below 3 s.

Quantifying physiological responses during simulated tasks among Canadian firefighters: A systematic review and meta-analysis

LAY SUMMARY

Firefighting involves a high level of physical exertion with tremendous demands on the heart and body. It is necessary to quantify levels of physical work exertion in firefighting to set physical fitness standards firefighters need to meet to improve performance, efficiency, and possibly decrease injury risks. Researchers need to focus on and develop exercise programs that are specific to firefighters so that they can be prepared and able to do their work safely.

Prevalence of coronary artery disease risk factors in firefighters in the city of Cape Town fire and rescue service - A descriptive study

Background: Over 45% of firefighter deaths are attributable to sudden cardiac death related to coronary artery disease (CAD), with many of these deaths attributed to comorbidities. The purpose of the study is to determine the prevalence of coronary artery disease (CAD) risk factors in firefighters in the City of Cape Town (CoCT). Design and Methods: The study used a quantitative, cross-sectional and descriptive design. A total of 124 full-time firefighters were conveniently recruited between September and November 2019 from the City of Cape Town Fire and Rescue Service. Results: The most prevalent CAD risk factors among firefighters were hypertension (33.1%), obesity (37.1%), cigarette smoking (39.5%) and dyslipidaemia (40.3%). A total of 41.9% of firefighters were categorized as low-risk, 54.8% as moderate-risk, and 3.2% as high-risk for CAD. Conclusion: The majority of firefighters had at least one CAD risk factor, with older males having the highest prevalence of multiple CAD risk factors. Compared to other regions of the world, the (CoCT) firefighters have higher prevalence of dyslipidaemia and cigarette smoking. Preventative behavioural strategies and education on CAD should be promoted to mitigate the development of CAD.

Influence of Body Composition on Post-Exercise Parasympathetic Reactivation of Firefighter Recruits

Firefighters have a sustained risk for experiencing a sudden cardiac event after completing a fire call. Heart rate recovery (HRR) can be utilized to characterize autonomic nervous system (ANS) recovery and has been linked to cardiac events. Research suggests that body composition influences post-exercise HRR responses in non-firefighter populations. The purpose of this study was to examine the influence of body mass index (BMI), waist circumference (WC), and percent body fat (BF) on the HRR response of firefighter recruits. BMI (kg·m-2), WC (cm), and BF (%) data from 57 firefighter recruits were collected. HRR (b·min-1) data were collected at completion (HR0), as well as 15 (HR15), 30 (HR30), 45 (HR45), 60 (HR60), 120 (HR120), and 180 (HR180) seconds following a submaximal step test, and commonly utilized clinical HRR indices were calculated (ΔHRR30, ΔHRR60, ΔHRR120, and ΔHRR180). After controlling for sex, linear mixed regression models did not identify significant interactions between body composition (ps > 0.05) and HRR response across time. However, significant (ps < 0.05) indirect semi-partial correlations were identified between BF and ΔHRR30 (rsp = -0.31) and ΔHRR60 (rsp = -0.27), respectively. Reducing overall BF (vs. BMI or WC) should be prioritized to improve the post-exercise ANS recovery of firefighter recruits.

Influence of a Training Academy on the Parasympathetic Nervous System Reactivation of Firefighter Recruits-An Observational Cohort Study

Sudden cardiac death (SCD) is the leading type of line-of-duty death among firefighters. An inability to restore parasympathetic nervous system (PSNS) control after activity is associated with SCD. Post-exercise heart rate recovery (HRR) provides unique insight into reactivation of the PSNS. Thus, the purpose of this study was to examine longitudinal changes in HRR responses of 25 male firefighter recruits. HR data were collected after submaximal exercise at week 1 (W1), week 6 (W6), and week 15 (W15) of their training at an academy. Percent maximal heart rate (%MHR) measures were computed at each HRR time point (%MHR0, %MHR15, %MHR30, %MHR45, %MHR60, %MHR120, %MHR180) and absolute HRR values were calculated at 30 s (ΔHRR30), 60 s (ΔHRR60), 120 s (ΔHRR120), and 180 s (ΔHRR180). After controlling for age and percent body fat, there was no statistically significant interaction between Week × HRR (p = 0.730), and there were no changes in ΔHRR30, ΔHRR60, and ΔHRR120, and ΔHRR180 indices across time. However, %MHR at W6 and W15 was significantly lower than %MHR at W1 at every HRR time point (ps < 0.001). Therefore, although the firefighter recruit training academy elicited positive training adaptations, changes in PSNS reactivation after submaximal activity were not identified.

Firefighting Induces Acute Inflammatory Responses that are not Relieved by Aspirin in Older Firefighters

OBJECTIVE

Sudden cardiac events account for 40% to 50% of firefighter line-of-duty deaths. Inflammatory proteins are strong biomarkers of cardiovascular inflammation. The present study investigated the effects of aspirin supplementation on inflammatory biomarkers following firefighting.

METHODS

Using a randomized, placebo-controlled, double-blind crossover design, 24 male firefighters (48.2 ± 5.9 years) were allocated into four conditions: acute (81 mg; single-dose) aspirin and placebo supplementation, and chronic (81 mg; 14 days) aspirin and placebo supplementation. Inflammatory proteins [interleukin (IL)-6, C-reactive protein (CRP), intracellular adhesion molecule (ICAM)-1, P-selectin, matrix metalloproteinase-9 (MMP-9)] and antioxidant potential [total antioxidant capacity (TAC)] were measured pre- and post-structural firefighting drills.

RESULTS

Firefighting activities significantly increased IL-6, MMP-9, and P-Selectin; however, no changes in TAC and ICAM-1 were detected. Neither acute nor chronic aspirin supplementation attenuated this inflammatory response.

CONCLUSION

Firefighting significantly increases inflammatory biomarkers and neither acute nor chronic low-dose aspirin mitigates this response.

Steady State Hydration Levels of Career Firefighters in a Large, Population-Based Sample

OBJECTIVES

To establish the extent of steady state hypohydration among firefighters and examine factors associated with their hydration status.

METHODS

Data on 450 career firefighters from 11 randomly selected fire departments had their body composition, total body water (TBW), and hypohydration status assessed using bioelectrical impedance. Measured height and weight were used to determine body mass index (BMI) and weight classification.

RESULTS

The hypohydration rate was 17% and 94% of hypohydrated firefighters were obese. A one-unit increase in BMI was associated with an 83% greater likelihood of being hypohydrated.

CONCLUSIONS

This study indicates that steady state hypohydration is a significant issue among obese firefighters. Current hydration policies based on previous reports that most (more than 90%) firefighters are hypohydrated in the steady state should be revisited and additional, confirmatory research in this area should be conducted.

Prevalence of cardiovascular risk factors in a population of French firefighters

Firefighters' activities increase the risk of sudden cardiac events. The main objective of this study was to describe the Loire firefighters' cardiovascular risk factors according to their cardiovascular risk and to their professional status. A retrospective study of the entire population of firefighters of the Loire department was conducted. Risk factors derived from the data collected during the occupational health follow-up medical examinations were described and the cardiovascular risk was assessed for 417 firefighters. The most frequent cardiovascular risk factors were: overweight and obesity (62.1%), high blood pressure (27.8%) and active smoking (16,1%). There were no significant differences between career firefighters and volunteers. The prevalence of risk factors for cardiovascular diseases is less than in the general population. Obesity remains the most common risk factor, especially among firefighters with high cardiovascular risk.

Worldwide prevalence of obesity among firefighters: a systematic review protocol

INTRODUCTION

Obesity may interfere with job performance and increase the risk of injury during firefighting activity. Obesity also has many deleterious effects on health indices and is associated with higher all-cause mortality. Studies report a high prevalence of obesity in the fire service. Also, firefighters' work schedule (12-hour to 24-hour shifts) and food availability during night shifts may be related to weight gain. Studies in American firefighters have shown annual weight gain between 0.5 and 1.5 kg. This study aims to report the obesity prevalence in the fire service to describe how it varies based on country and region, job status, type of firefighter and gender.

METHODS AND ANALYSIS

The main outcome evaluated will be obesity prevalence. We will systematically search the literature databases PubMed, Medline, Web of Science, Sportdiscus, Academic Search Premier, Cumulative Index of Nursing and Allied Health Literature (CINAHL), SciTech Premium Collection, Sports Medicine & Education Index, Research Library and Scopus. One reviewer will perform the search. Two independent reviewers will select studies, extract data from eligible studies and evaluate their methodological and reporting quality. Agreement between reviewers will be measured using Cohen's kappa. Other data of interest will include age, body mass index, body fat percentage, job status (career, volunteer or military), years of service and type of firefighter (eg, structural and wildland firefighter). We will produce a narrative summary of our findings. Tables will be generated to summarise data.

ETHICS AND DISSEMINATION

This systematic review does not require ethics clearance since published studies with non-identifiable data will be used. The results of the systematic review will be disseminated via publication in a peer-reviewed journal and through conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42019129122.

Mortality in a cohort of US firefighters from San Francisco, Chicago and Philadelphia: an update

OBJECTIVES

To update the mortality experience of a previously studied cohort of 29 992 US urban career firefighters compared with the US general population and examine exposure-response relationships within the cohort.

METHODS

Vital status was updated through 2016 adding 7 years of follow-up. Cohort mortality compared with the US population was evaluated via life table analyses. Full risk-sets, matched on attained age, race, birthdate and fire department were created and analysed using the Cox proportional hazards regression to examine exposure-response associations between select mortality outcomes and exposure surrogates (exposed-days, fire-runs and fire-hours). Models were adjusted for a potential bias from healthy worker survivor effects by including a categorical variable for employment duration.

RESULTS

Compared with the US population, mortality from all cancers, mesothelioma, non-Hodgkin's lymphoma (NHL) and cancers of the oesophagus, intestine, rectum, lung and kidney were modestly elevated. Positive exposure-response relationships were observed for deaths from lung cancer, leukaemia and chronic obstructive pulmonary disease (COPD).

CONCLUSIONS

This update confirms previous findings of excess mortality from all cancers and several site-specific cancers as well as positive exposure-response relations for lung cancer and leukaemia. New findings include excess NHL mortality compared with the general population and a positive exposure-response relationship for COPD. However, there was no evidence of an association between any quantitative exposure measure and NHL.

Physiologic strain of SCBA confidence course training compared to circuit training and live-fire training

Firefighting is a dangerous occupation and even training carries substantial risks. Self-contained breathing apparatus confidence courses (SCBACC) are a common type of training.

PURPOSE

Compare the physiological strain of SCBACC to live-fire training (LFT) and circuit training (CT) among academy cadets.

METHODS

Cadets wore physiologic status monitors to assess heart rate (HR) and estimated core temperature (ECT) during CT, LFT, and SCBACC of similar duration (33-38 min).

RESULTS

Data from 52 cadet firefighters (28 ± 4 yrs old) were analyzed. ECT (38.6 ± 0.4 vs 39.3 ± 0.7 vs. 39.3 ± 0.6ᵒC), peak HR (182.6 ± 9.1 vs. 192.7 ± 9.5 vs 195.9 ± 9.6 bpm), and age-predicted maximal HR (APMHR%; 94.6 ± 4.6 vs 99.9 ± 4.9 vs. 101.5 ± 4.8%) were significantly (p < 0.05) lower for CT than SCBACC and LFT, respectively.

CONCLUSIONS

SCBACC produced physiological strain greater than CT and similar to LFT. SCBACC resulted in sustained HR at 100% of age-predicted maximal values, a peak ECT of 39.3 °C, and should be considered as physiologically stressful as LFT.

Effects of Wrist Cooling on Recovery From Exercise-Induced Heat Stress With Firefighting Personal Protective Equipment

OBJECTIVE

To determine the effects of wrist cooling on recovery from exercise-induced heat stress (EIHS) from wearing firefighting personal protective equipment (PPE) and self-contained breathing apparatus.

METHODS

Using a single-blind, counterbalanced, crossover-design, in 11 healthy men, we measured heart rate (HR), HR variability (HRV), core temperature (TCore), thermal strain (TS), and fatigue at rest, during 30-minute of exercise in PPE+SCBA, and during recovery while wearing a wrist cooling band (control[off] vs cool[on]).

RESULTS

No differences were observed between trials at baseline or during exercise, in HR, TCore, TS, or fatigue. Time to 50% and recovery were not different between trials. Upon recovery, TCore was lower, while HR, fatigue, HRV, and TS were relatively indifferent with cooling.

CONCLUSION

Wrist cooling after EIHS only modestly enhanced recovery, questioning its implementation during on-scene rehabilitation of firefighters.

Examination of Strenuous Activity Preceding Cardiac Death during Firefighting Duties

Sudden cardiac death accounts for approximately 45% of duty-related fatalities among United States firefighters. Strenuous physical exertion is recognized as a trigger of sudden cardiac events. This study describes the duration of strenuous physical exertion on-scene preceding a fatal cardiac event by situation encountered during firefighting duties. Data provided by the National Institute for Occupational Safety and Health Fire Fighter Fatality Investigation and Prevention Program for duty-related firefighter fatalities over a 9-year period were analyzed. Among the 235 fatalities investigated, 45% had a cause of death that was cardiac in origin. Time (mean ± SD) spent on-scene in strenuous work was 30 ± 26 min, 14 ± 15 min, and 47 ± 52 min for fire, non-fire emergency, and training situations, respectively. Across all emergency operations and training, 31% of fatalities occurred among firefighters who performed ≤10 min of strenuous work, whereas 13% of fatalities occurred among those who performed >60 min. Study findings indicate that there is considerable variability in the duration of strenuous work preceding fatal cardiac events during firefighting duties. Notably, a high percentage of fatal cardiac events occurred after a relatively brief period of strenuous work, suggesting that the performance of any strenuous work, even that of short duration, may be sufficient to provoke a cardiac event in a firefighter with underlying cardiac disease.