The greatest metabolic demand during wildfire assignments occurred during ingress hikes. On average, this was close to the estimated metabolic demand of the job qualification arduous pack test. However, greater metabolic demand occurred for periods during both shift (on the job) and training hikes. These data quantify the demands associated with actual wildland performance of WLFFs and can help define future work capacity testing and training procedures.

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IntroductiondWildland firefighters (WLFF) work long hours in extreme environments, resulting in high daily total energy expenditure. Increasing work-shift eating episodes and/or providing rations that promote convenient eating has shown augmented self-selected work output, as has regular carbohydrate (CHO) consumption. It remains unclear how current WLFF feeding strategies compare to more frequent nutrient delivery. Our aim was to determine WLFFs' self-selected field total energy intake (TEI), composition, and feeding patterns during wildland fire suppression shifts. MethodsdWLFF were deployed to fire incidents across the United States throughout the 2018 fire season. Preshift food inventories collected at basecamp provided item-specific nutrient content (kilocalories, CHO, fat, protein). Work shift consumption (TEI, feeding frequency, episodic composition) was monitored in real time by field researchers on fireline via observational data capture using mobile tablets. Shift work output was also quantified via actigraph accelerometry. ResultsdEighty-six WLFF (27.5±6.4 y; 16 female, 70 male) worked 14.0±1.1 h shifts, with a TEI of 6.3±2.5 MJ (1494±592 kcal) (51±10, 37±9, 13±4% for CHO, fat, and protein, respectively). WLFF averaged 4.3±1.6 eating episodes (1.4±1.3 MJ [345±306 kcal] and 44±38 g CHO$episode-1). WLFF who consumed >20 kcal$kg-1 averaged less sedentary activity than those consuming <16 kcal$kg-1. Data are presented as mean±SD. ConclusionsdNot including fire camp meals (breakfast, dinner), the present work-shift TEI approximates 33% of previously determined WLFF total energy expenditure and demonstrates that current WLFF consumption patterns may not deliver adequate nutrients for occupational demands.

Wildland fire fighting is a high-risk occupation requiring considerable physical and psychological demands. Multiple agencies publish fatality summaries for wildland firefighters; however, the reported number and types vary. At least five different surveillance systems capture deaths, each with varying case definitions and case inclusion/exclusion criteria. Four are population-level systems and one is case-based. System differences create challenges to accurately characterize fatalities. Data within each of the five surveillance systems were examined to better understand the types of wildland firefighter data collected, to assess each system’s utility in characterizing wildland firefighter fatalities, and to determine each system’s potential to inform prevention strategies. To describe similarities and differences in how data were recorded and characterized, wildland fire deaths for three of the population-based systems were matched and individual fatalities across systems were compared. Between 2001 and 2012, 247 unique deaths were captured among the systems; 73% of these were captured in all three systems. Most common causes of death in all systems were associated with aviation, vehicles, medical events, and entrapments/burnovers. The data show that, although the three systems often report similar annual summary statistics, events captured in each system vary each year depending on the types of events that the system is designed to track, such as inclusion/exclusion of fatalities associated with the Hometown Heroes Survivor Benefits Act of 2003. The overarching and central goal of each system is to collect accurate and timely information to improve wildland firefighter safety and health. Each system is unique and has varying inclusion and exclusion criteria for capturing and tracking different subsets of wildland firefighter tasks and duties. Use of a common case definition and better descriptions and interpretations of the data and the results would help to more accurately characterize wildland firefighter traumatic injuries and illnesses, lessen the likelihood for misinterpretation of wildland firefighter fatality data, and assist with defining the true occupational injury burden within this high-risk population.

Context: Telemetric core-temperature monitoring is becoming more widely used as a noninvasive means of monitoring core temperature during athletic events.Objective: To determine the effects of sensor ingestion timing on serial measures of core temperature during continuous exercise.Design: Crossover study. Setting: Outdoor dirt track at an average ambient temperature of 4.46C 6 4.16C and relative humidity of 74.1% 6 11.0%.Patients or Other Participants: Seven healthy, active participants (3 men, 4 women; age 5 27.0 6 7.5 years, height 5 172.9 6 6.8 cm, body mass 5 67.5 6 6.1 kg, percentage body fat 5 12.7% 6 6.9%, peak oxygen uptake [V O 2peak ] 5 54.4 6 6.9 mLNkg 21 Nmin 21 ) completed the study.Intervention(s): Participants completed a 45-minute exercise trial at approximately 70% V O 2peak . They consumed coretemperature sensors at 24 hours (P1) and 40 minutes (P2) before exercise.Main Outcome Measure(s): Core temperature was recorded continuously (1-minute intervals) using a wireless data logger worn by the participants. All data were analyzed using a 2-way repeated-measures analysis of variance (trial 3 time), Pearson product moment correlation, and Bland-Altman plot.Results: Fifteen comparisons were made between P1 and P2. The main effect of time indicated an increase in core temperature compared with the initial temperature. However, we did not find a main effect for trial or a trial 3 time interaction, indicating no differences in core temperature between the sensors (P1 5 38.36C 6 0.26C, P2 5 38.36C 6 0.46C).Conclusions: We found no differences in the temperature recordings between the 2 sensors. These results suggest that assumed sensor location (upper or lower gastrointestinal tract) does not appreciably alter the transmission of reliable and repeatable measures of core temperature during continuous running in the cold.Key Words: thermal response, continuous exercise, body temperature Key Points N The telemetric core-temperature sensors recorded consistent core-temperature data independent of the time of ingestion and the assumed location of the sensor in the lower gastrointestinal tract during continuous running in the cold.N The wireless core-temperature sensors could give health care providers a reliable way to track core-temperature changes in athletes during sporting events and to respond more effectively to heat-related symptoms in at-risk participants.T he practical ability to monitor core body temperature might be critical in athletic settings where the probability for developing heat or cold illness is elevated 1 and athletic performance subsequently decreases. 2 The more common methods for measuring core temperature include pulmonary artery, esophageal, rectal, and temporal measurements, which are impractical in a sport or occupational setting. Each of these measurement techniques has different applications for various scenarios. Pulmonary arterial blood temperature is measured with insertion of a catheter into the right pulmonary artery. 3 Measuring esophageal temperature involves positioni...

Throughout the United States, wildland firefighters respond to wildfires, performing arduous work in remote locations. Wildfire incidents can be an ideal environment for the transmission of infectious diseases, particularly for wildland firefighters who congregate in work and living settings. In this review, we examine how exposure to wildfire smoke can contribute to an increased likelihood of SARS-CoV-2 infection and severity of coronavirus disease (COVID-19). Human exposure to particulate matter (PM), a component of wildfire smoke, has been associated with oxidative stress and inflammatory responses; increasing the likelihood for adverse respiratory symptomology and pathology. In multiple epidemiological studies, wildfire smoke exposure has been associated with acute lower respiratory infections, such as bronchitis and pneumonia. Co-occurrence of SARS-CoV-2 infection and wildfire smoke inhalation may present an increased risk for COVID-19 illness in wildland firefighters due to PM based transport of SARS CoV-2 virus and up-regulation of angiotensin-converting enzyme II (ACE-2) (i.e. ACE-2 functions as a trans-membrane receptor, allowing the SARS-CoV-2 virus to gain entry into the epithelial cell). Wildfire smoke exposure may also increase risk for more severe COVID-19 illness such as cytokine release syndrome, hypotension, and acute respiratory distress syndrome (ARDS). Current infection control measures, including social distancing, wearing cloth masks, frequent cleaning and disinfecting of surfaces, frequent hand washing, and daily screening for COVID-19 symptoms are very important measures to reduce infections and severe health outcomes. Exposure to wildfire smoke may introduce additive or even multiplicative risk for SARS-CoV-2 infection and severity of disease in wildland firefighters. Thus, additional mitigative measures may be needed to prevent the co-occurrence of wildfire smoke exposure and SARS-CoV-2 infection.

ObjectivesIn order to make recommendations to protect wildland firefighters (WLFFs) from heat-related illness, the role physical exertion plays on core body temperature (Tc) in the work environment needs to be considered. We aimed to estimate the association of time-varying job tasks with differing exertion levels on change in Tc, among WLFFs engaged in fire management activities, while controlling for ambient conditions and individual characteristics. In addition, we examined whether duration of tasks modified the relationship between task and change in Tc.MethodsWe used data from The Wildland Firefighter Heat Related Illness study, a repeated measures study with individual-level data on 301 WLFFs from 2013 to 2016. Job tasks over one full shift were recorded and categorised into four levels (sedentary, light, moderate and high) based on estimated exertion levels. Tc was measured every 15 s using an ingestible sensor and personal monitors measured ambient conditions. The analysis used generalised estimating equations with an autoregressive correlation structure.ResultsWe found statistically significant associations between job tasks with increased physical demand and increases in Tc. When compared with sedentary tasks, the estimated increases in Tc for light, moderate and high activity tasks of average duration were 0.07°C (95% CI 0.02 to 0.11°C), 0.19°C (95% CI 0.15 to 0.23) and 0.44°C (95% CI 0.39 to 0.49°C), respectively. In addition, we found evidence of interaction between task type and duration.ConclusionsThis study supports the hypothesis that occupational exposure to physical exertion increases Tc, highlighting the need to update recommendations to protect WLFFs from heat-related illness.

We observed significant links between a greater number of years as a WLFF and self-report of two subclinical cardiovascular risk factors as well as markers of musculoskeletal health. Additional studies are needed to determine if findings can be generalized to all WLFFs.