BACKGROUND: Physical activity for any purpose counts toward meeting Physical Activity Guidelines (PAG). However, national surveillance systems traditionally focus on leisure-time physical activity. There is an incomplete understanding of the association between meeting PAG in leisure time and occupation activity level among US workers. METHODS: We used cross-sectional 2020 National Health Interview Survey data to examine US adults aged 18-64 years who worked the week before the survey (n = 14,814). We estimated the proportion meeting aerobic and muscle-strengthening PAG in leisure time by occupation activity level (low, intermediate, and high). Using logistic regression, we examined the association between meeting PAG in leisure time and occupation activity level, adjusted for sociodemographic characteristics and stratified by hours worked. We compared the sociodemographic characteristics of adults working ≥40 hours (the previous week) in high-activity occupations to those in low- or intermediate-activity occupations. RESULTS: Adults working in high-activity occupations were less likely to meet PAG in leisure time (26.1% [24.3-28.1]) versus those in low-activity (30.6% [29.1-32.2], P < .01) or intermediate-activity (32.4% [30.8-34.2]) occupations. In stratified, adjusted models, adults working ≥40 hours in low- and intermediate-activity occupations were 13% and 20%, respectively, more likely to meet PAG in leisure time versus those in high-activity occupations. Among those working ≥40 hours, adults in high-activity occupations were more likely to be Hispanic or Latino, male, younger, and have a high school education or lower compared with those in less active occupations. CONCLUSION: Traditional surveillance may underestimate meeting PAG among people working in high-activity occupations, potentially disproportionately affecting certain groups.

Background: Firefighters are at high risk for nonfatal and fatal occupational injuries. While some past research has quantified firefighter injuries using various data sources, Ohio workers’ compensation injury claims data largely have not been used. Methods: Public and private firefighter claims, including volunteer and career firefighters, from Ohio's workers’ compensation data for 2001–2017 were identified based on occupational classification codes and manual review of the occupation title and injury description. The task during injury (firefighting, patient care, training, other/unknown, etc.) was manually coded based on the injury description. Injury claim counts and proportions were described across claim type (medical-only or lost-time), worker demographics, task during injury, injury events, and principal diagnoses. Results: 33,069 firefighter claims were identified and included. Most claims were medical-only (66.28%, <8 days away from work) and involved males (93.81%) aged 25-54 years (86.54%). While the task during injury could not be categorized for many narratives (45.96%), the largest percentage that could be categorized occurred during firefighting (20.48%) and patient care (17.60%). The most common injury events were overexertion involving outside sources (31.33%) and struck by objects or equipment (12.68%). The most frequent principal diagnoses were back, lower extremity, and upper extremity sprains (16.02%, 14.46%, and 11.98%, respectively). Conclusions: This study provides a preliminary basis for the development of focused firefighter injury prevention programming and training. Obtaining denominator data, enabling rate calculation, would strengthen the risk characterization. Based on the current data, prevention efforts focusing on the most frequent injury events and diagnoses may be warranted. © 2023 National Safety Council and Elsevier Ltd

Background: Firefighters are at high risk for nonfatal and fatal occupational injuries. While some past research has quantified firefighter injuries using various data sources, Ohio workers compensation injury claims data largely have not been used. Methods: Public and private firefighter claims, including volunteer and career firefighters, from Ohio's workers compensation data for 20012017 were identified based on occupational classification codes and manual review of the occupation title and injury description. The task during injury (firefighting, patient care, training, other/unknown, etc.) was manually coded based on the injury description. Injury claim counts and proportions were described across claim type (medical-only or lost-time), worker demographics, task during injury, injury events, and principal diagnoses. Results: 33,069 firefighter claims were identified and included. Most claims were medical-only (66.28%, <8 days away from work) and involved males (93.81%) aged 25-54 years (86.54%). While the task during injury could not be categorized for many narratives (45.96%), the largest percentage that could be categorized occurred during firefighting (20.48%) and patient care (17.60%). The most common injury events were overexertion involving outside sources (31.33%) and struck by objects or equipment (12.68%). The most frequent principal diagnoses were back, lower extremity, and upper extremity sprains (16.02%, 14.46%, and 11.98%, respectively). Conclusions: This study provides a preliminary basis for the development of focused firefighter injury prevention programming and training. Obtaining denominator data, enabling rate calculation, would strengthen the risk characterization. Based on the current data, prevention efforts focusing on the most frequent injury events and diagnoses may be warranted. 2023 National Safety Council and Elsevier Ltd

PURPOSE: Postural imbalance can result from hyperthermia mediated muscular fatigue and is a major factor contributing to injuries from falling. The objective of this study was to investigate the effect of exercise-induced hyperthermia and the impact of cooling on postural balance while wearing firefighters' protective clothing (FPC) in a hot environment. METHODS: A portable force platform measured postural balance characterized by postural sway patterns using center of pressure metrics. Twelve healthy, physically fit males were recruited to stand on the force platform once with eyes open and once with eyes closed before and after treadmill exercise (40% V˙O(2max)) inside an environmental chamber under hot and humid conditions (30 °C and 70% relative humidity) while wearing FPC. Subjects participated in two randomly assigned experimental phases: control and cooling intervention. RESULTS: A significant increase in physiological responses and postural balance metrics was observed after exercising in the heat chamber while wearing FPC. Cooling resulted in a significant effect only on postural sway speed after exercise-induced hyperthermia. CONCLUSIONS: Hyperthermia can negatively alter postural balance metrics, which may lead to an increased likelihood of falling. The utilization of body cooling reduced the thermal strain but had limited impact on postural balance stability.

This study compared exercise performance and comfort while wearing an N95 filtering facepiece respirator (N95), cloth mask, or no intervention control for source control during a maximal graded treadmill exercise test (GXT). Twelve Division 1 athletes (50% female, age = 20.1 ± 1.2, BMI = 23.5 ± 1.6) completed GXTs under three randomized conditions (N95, cloth mask, control). GXT duration, heart rate (HR), respiration rate (RR), transcutaneous oxygen saturation (SpO(2)), transcutaneous carbon dioxide (TcPCO(2)), rating of perceived exertion (RPE), and perceived comfort were measured. Participants ran significantly longer in control (26.06 min) versus N95 (24.20 min, p = 0.03) or cloth masks (24.06 min, p = 0.04). No differences occurred in the slope of HR or SpO(2) across conditions (p &gt; 0.05). TcPCO(2) decreased faster in control (B = -0.89) versus N95 (B = 0.14, p = 0.02) or cloth masks (B = -0.26, p = 0.03). RR increased faster in control (B = 8.32) versus cloth masks (B = 6.20, p = 0.04). RPE increased faster in the N95 (B = 1.91) and cloth masks (B = 1.79) versus control (B = 1.59, p &lt; 0.001 and p = 0.05, respectively). Facial irritation/itching/pinching was higher in the N95 versus cloth masks, but sweat/moisture buildup was lower (p &lt; 0.05 for all). Wearing cloth masks or N95s for source control may impact exercise performance, especially at higher intensities. Significant physiological differences were observed between cloth masks and N95s compared to control, while no physiological differences were found between cloth masks and N95s; however, comfort my differ.

Background: The physical activity (PA) health paradox hypothesizes that occupational physical activity (OPA) and leisure time PA have differential cardiovascular health effects due to increased cardiovascular load without adequate recovery; however, research describing worker PA lacks high-quality objective OPA measurement. This study aimed to objectively describe PA profiles of men reporting high OPA and make comparisons to aerobic PA and OPA recommendations. Methods: Male food service, material moving, health care, or maintenance workers wore activity (ActiGraph(®) and activPAL(®)) and heart rate monitors for 7 days. Participants recorded work, non-work, and sleep times in a diary. PA was operationalized as time spent in sedentary behavior, upright time, light, moderate, vigorous, and moderate-to-vigorous PA during work and non-work hours. PA profiles were described and compared with Centers for Disease Control and Prevention aerobic PA guidelines (≥21.4 minute/day) and OPA recommendations (<30 minute/hour upright and intensity of <30% heart rate reserve). Findings: Nineteen male workers (68% White, age = 46.6±7.9 years) were more active on workdays than non-workdays (sedentary: 492.3 vs. 629.7 minute/day; upright: 462.4 vs. 325.2 minute/day; moderate-to-vigorous PA: 72.4 vs. 41.5 minute/day, respectively; all p < .05). Most participants (17/19) achieved aerobic PA guidelines across all days with more achieving on workdays (19/19) than non-workdays (13/19). OPA often exceeded recommended limits with participants accumulating 39.6±12.2 minutes/work hour upright and 30.3±25.9% of working time >30% heart rate reserve. Conclusions/Application to Practice: Male workers reporting high OPA typically met aerobic PA guidelines but exceeded recommended OPA limits. The long-term health implications of such activity profiles should be investigated.

Background Fire protective ensembles (FPEs) are essential to safely perform firefighting job tasks; however, they are often burdensome to the workers. The aim of this study was to compare three internationally certified fire protective ensembles from the European Union (EU), South Korea (SK), and United States (US) on physiological responses, mobility, and comfort. Methods Ten male professional firefighters performed a battery of exercises in the laboratory following the ASTM F3031-17 standard to evaluate mobility, occupation-specific performance, and physiological responses (body weight, heart rate (HR), core temperature (Tc), breathing rate (BR), and rating of perceived exertion (RPE)) to 20 min of treadmill walking (3.2 mph, 5% incline). All participants carried out the evaluation wearing each FPE in a random order. Mixed effects models examined time (pre-vs. post-) by ensemble (EU, SK, US) interactions for all physiological variables and compared comfort, performance, and subjective variables across ensembles. Results No interaction effects were observed for body weight, HR, Tc, BR, or RPE (p = 0.890, p = 0.994, p = 0.897, p = 0.435, and p = 0.221; respectively). SK had greater trunk flexion than EU (78.4° vs. 74.6°, p = 0.026) and US had lower standing reach than EU (105.5 cm vs. 115.4 cm, p = 0.004). Agility circuit time was lower in US (9.3 s) compared to EU (9.8 s) or SK (9.9 s) (p = 0.051 and p = 0.019, respectively). Conclusions The findings suggest that physiological burden remained largely unchanged across the international FPEs. However, mobility, performance, and comfort may be significantly influenced across types. International stakeholders and end users should consider design implications when choosing fire protective ensembles.

OBJECTIVES: Recent evidence suggests that occupational physical activity (OPA) is associated with adverse cardiovascular health, whereas leisure time physical activity is protective. This study explored explanatory physiological mechanisms. METHODS: Nineteen males (68% white, age=46.6±7.9 years, body mass index=27.9±5.1 kg/m(2)) with high self-reported OPA wore activity (ActiGraph and activPAL) and heart rate (HR) monitors for 7 days and an ambulatory blood pressure (BP) monitor on one workday and one non-workday. Mixed effects models compared cardiovascular variables (24-hour, nocturnal, waking and non-work time HR and BP) and nocturnal HR variability (HRV) on workdays versus non-workdays. Additional models examined associations of daily activity (steps, light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA)) with cardiovascular variables. Workday by daily activity interactions were examined. RESULTS: 24-hour and waking HR and diastolic BP as well as non-work diastolic BP were significantly higher on workdays versus non-workdays (p<0.05 for all). However, no difference in systolic BP or nocturnal HR or BP was observed between work and non-workdays (p>0.05 for all). Low-frequency and high-frequency power indices of nocturnal HRV were lower on workdays (p<0.05 for both). Daily steps and LPA were positively associated with 24-hour and waking HR on work and non-workdays. Significant interactions suggested MVPA increases HR and lowers nocturnal HRV during workdays, with the opposite effect on non-workdays. CONCLUSIONS: Cardiovascular load was higher on workdays versus non-workdays with no compensatory hypotensive response following workdays. Daily MVPA may differentially affect ambulatory cardiovascular load and nocturnal HRV on workdays versus non-workdays, supporting the physical activity health paradox hypothesis.

Firefighters' protective clothing (FPC) can limit human thermoregulation due to limited water vapor permeability and insulation. This study investigated the effect of cooling on the physiological responses and probability of hyperthermia in subjects wearing FPC during exercise in a hot environment. Twelve males participated in this study. A maximal graded treadmill exercise test was performed to measure maximal oxygen uptake (V̇O(2max)) and to assess subjects' capacity to perform the assigned exercise. Exercise included treadmill walking at 40% V̇O(2max) in warm (30 °C) and humid (70% RH) conditions for 40 min while wearing FPC. Subjects participated in two randomly counterbalanced assigned experimental protocols: control (no cooling) and intervention (cooling). The experimental intervention consisted of a cooling garment infused with cooled water (18 °C) through silastic tubing sewn into the fabric and worn underneath FPC. Each subject served as their own control and, therefore, completed both the control and intervention of the protocol. A logistic regression model was used to analyze the interaction effect of cooling on the probability of progression to hyperthermia (T(c) ≥ 38 °C). Subjects' physiological responses increased during exercise in a warm and humid environment. Active cooling decreased (p < 0.05) the thermal stress thereby reducing the probability of hyperthermia while exercising in hot and humid conditions. The results indicate that when cooling was used each subject, on average, was 91% less likely to reach the lower threshold limit of hyperthermia. Exercise in hot environments while wearing FPC results in significant physiological strain, which may lead to hyperthermia. Utilization of a cooling garment reduced physiological strain and the probability of hyperthermia.

BACKGROUND: Emerging evidence, predominately from European and Asian countries, describes opposing effects of occupational physical activity (OPA) and leisure-time physical activity (LTPA) on cardiovascular health. This analysis examined cardiovascular disease (CVD) prevalence associated with OPA and LTPA. METHODS: This cross-sectional analysis of 2015 National Health Interview Survey data (n=16 974) employed logistic regression to estimate odds (OR) of self-reported CVD (coronary heart disease, heart attack, stroke or angina) with self-reported total occupational activity (TOA), occupational exertion (OE), occupational standing and walking (OSW) and LTPA. OPA was measured using two questions: 'How often does your job involve…' (1) 'repeated lifting, pushing, pulling or bending?' (OE) and (2) 'standing or walking around?' (OSW) with responses on a 5-item Likert scale (0=never, 4=always). TOA was categorised similarly after summing OE and OSW scores. LTPA was defined as 0, 1-149 or ≥150 min/week of moderate-to-vigorous activity. All models adjusted for common socioeconomic variables and additional analyses were stratified by sex, smoking status and LTPA. RESULTS: Odds for CVD were higher when 'always' performing TOA (OR 1.99 95% CI 1.12 to 3.53), OE (OR 2.15, 95% CI 1.45 to 3.19) or OSW (OR 1.84, 95% CI 1.07 to 3.17) compared with 'never'. When restricting to never-smokers, odds for CVD were higher when 'always' performing TOA (OR 3.00, 95% CI 1.38 to 6.51) and OE (OR 3.00, 95% CI 1.80 to 5.02) versus 'never'. CONCLUSION: Associations of high OPA with CVD were equally apparent across sexes, stronger in lower LTPA levels and stronger in never-smokers. While uncontrolled confounding is still possible, even after extensive adjustment, the seemingly paradoxical adverse associations with OPA and CVD should be investigated further.

Firefighting is physically and mentally strenuous, requiring rapid, appropriate decision-making in hot environments. Intact cognitive function is imperative to firefighters' effectiveness and safety. The study purpose was to investigate the effect of hyperthermia and the effect of body cooling on sustained attention and response inhibition while wearing firefighters' personal protective ensembles after exercise in a hot environment. Twelve healthy males were recruited to participate in two randomly assigned exercise sessions (walking on a treadmill for 40 min at 40% [Formula: see text] O2max while wearing firefighter's protective ensemble) in a hot environment: control (no cooling) and intervention (cooling). For intervention sessions, a cooling garment was worn underneath firefighter's protective ensemble and infused with 18 degrees C water supplied by an external water circulator. Participants performed a computerized Go/No-Go (a measure of cognitive function) test three times at baseline and post-exercise for each experimental session. Participants completed baseline testing while wearing cotton athletic clothing. The exercise continued until the core temperature reached approximately 39 degrees C (for all subjects regardless of cooling or non-cooling experimental sessions). Following hyperthermia, participants' physiological responses were significantly increased after exercise. Subjects' reaction time was significantly reduced (improved) after experiencing thermal strain and reaching hyperthermia. The cooling method had a significant impact on suppressing the physiological load, i.e., body cooling delayed the time to reach a Tc of 39 degrees C (p </= 0.05), but not cognitive inhibition and attention (reaction time and accuracy). Unexpectedly, hyperthermia resulted in shorter reaction time following exercise (16.64 +/- 5.62; p < 0.03), likely influenced by increased attention/vigilance. Hyperthermia may trigger an acute increase in alertness, causing decreased reaction time.

BACKGROUND: Individual social support is positively related to physical activity participation. However, less is known about how neighborhood-level social structures relate to physical activity participation. METHODS: We analyzed 2017 National Health Interview Survey data for adult participants who completed all questions on physical activity and neighborhood cohesion (N = 23,006). Each cohesion question was binary coded (cohesion or not) and used as a predictor individually and for a composite score measuring total social cohesion. We used linear regression to estimate minutes of moderate aerobic activity, and we used logistic regression to estimate the odds of meeting aerobic guidelines (>/=150 min/wk), strength guidelines (>/=2 d/wk of muscle strengthening exercises), or both guidelines, predicted by the 5 definitions of cohesion (composite cohesion and the 4 questions separately). Models were adjusted for sex, age, race/ethnicity, family-income-to-poverty ratio, education, nativity, language, and neighborhood tenure. RESULTS: Respondents who reported having more social cohesion had 45.0 more minutes of aerobic activity and increased odds of meeting aerobic, strength, and combined guidelines (odds ratio [OR] = 1.22, OR = 1.13, and OR = 1.14, respectively; P < .01 for all). Reporting having availability of help when needed, neighbors to count on, trustworthy neighbors, and close-knit neighbors all resulted in increased odds of meeting aerobic guidelines but not increased odds for meeting strength guidelines in the latter 3 components or combined guidelines for the latter 2 components. CONCLUSIONS: Having neighborhood social cohesion or select individual components of neighborhood cohesion are positively related to meeting aerobic, strength, and combined guidelines.

AbstractThis study aimed to determine if trunk posture during walking is related to increases in rectal temperature (Tre). 24 males treadmill walked in one of four conditions (1): 30 min at 3.0 mph and 0% grade, 20C and 50% relative humidity (RH), wearing healthcare worker (HCW) PPE; (2): 30 min at 3.0 mph and 0% grade, 27.5C and 60% RH, HCW PPE; (3): 30 min at 3.0 mph and 0% grade, 32.5C and 70% RH, HCW PPE; and (4): 40 min at 40% VO2max, 30C and 70% RH, wearing firefighter PPE. Trunk posture (Zephyr BioHarness 3) and Tre were measured continuously. Tre was positively related to trunk posture, controlling for covariates (B=3.49, p<.001). BMI and age moderated this relationship (Tre age, B = 0.76, p<.001; Tre*BMI, B=1.85, p<.001). Trunk posture measurement may be useful in monitoring fall potential and magnitude of heat stress of workers in hot environments.Practitioner Summary: Occupational hyperthermia increases worker risk for heat illness and injury but is difficult to monitor in the field. This investigation shows that trunk posture is independently and positively related to core temperature. Non-invasive measurement or visual inspection of trunk posture could provide novel insight on individual heat strain level.

Introduction: Elevated ambient temperature and personal protective clothing (PPC) induce physiological strain which may be counteracted by heat acclimation. The purpose of this study was to determine if 5-day heat acclimation training (HAT) improves thermal and perceptual responses while wearing chemical, biological, radiological, and nuclear (CBRN) PPC. Methods: Nine healthy men completed a heat stress test (walking for one hour with CBRN PPC) in 35 degrees C and 50% relative humidity (RH) before and after 5-day HAT. The HAT consisted of five consecutive days of two 45-minute cycling sessions (50% VO2max) wearing athletic clothing separated by a 15 min rest in 45 degrees C and 20% RH. Results of the pre- and post- HAT heat stress tests were compared. Results: Heat acclimation was seen through 5-day HAT; however, thermoregulatory responses did not improve while wearing CBRN PPC. Improvement (p<0.05, day 1 vs. day 5 HAT) in skin temperature (38.0+/-0.5 degrees C vs. 37.6+/-0.5 degrees C), body temperature (38.6+/-0.4 degrees C vs. 38.3+/-0.4 degrees C), sweat rate (2.26+/-0.3kg vs. 2.64+/-0.3kg), RPE (15.8+/-2.4 vs. 13.9+/-3.1), and heat perception (5.7+/-0.6 vs. 4.9+/-1.0) were noted. However, no physiological or perceptual improvements (p>0.05) were found in the post-HAT heat stress test. Conclusions: Heat acclimation adaptations may be blunted by CBRN PPC, thus requiring differing or extended HAT.

Seo, Yongsuk, Jeremiah Vaughan, Tyler D. Quinn, Brittany Followay, Raymond Roberge, Ellen L. Glickman, and Jung-Hyun Kim. The effect of inspiratory resistance on exercise performance and perception in moderate normobaric hypoxia. High Alt Med Biol. 00:000-000, 2017. PURPOSE: Respirators are simple and efficient in protecting workers against toxic airborne substances; however, their use may limit the physical performance of workers. The purpose of this study was to determine the effect of inspiratory resistance on physical performance and breathing perception in normobaric hypoxia. METHOD: Nine healthy men wore a tight-fitting respiratory mask outfitted with one of four different inspiratory resistors (R) (0, 1.5, 4.5, 7.5 cm H2O/L/Sec) while exercising at normobaric hypoxia (17% O2) at submaximal exercise workloads of 50, 100, and 150 W on a cycle ergometer for 10 minutes each, followed by a maximal oxygen uptake (VO2max) test to exhaustion. RESULTS: Maximal power output at R7.5 was significantly lower than R0 (p = 0.016) and R1.5 (p = 0.035). Respiration rate was significantly reduced at R4.5 (p = 0.011) and R7.5 (p ≤ 0.001) compared with R0. Minute ventilation was significantly decreased in R7.5 compared with R0 (p = 0.003), R1.5 (p = 0.010), and R4.5 (p = 0.016), whereas VO2 was not significantly changed. Breathing comfort (BC) and breathing effort (BE) were significantly impaired in R7.5 (BC: p = 0.025, BE: p = 0.001) and R4.5 (BC: p = 0.007, BE: p = 0.001) compared with R0, but rating of perceived exertion (RPE) remained unchanged. CONCLUSIONS: Added inspiratory resistance limited maximal power output and increased perceptions of BC and BE in normobaric hypoxia. However, low-to-moderate inspiratory resistance did not have a deleterious effect on VO2 or RPE at submaximal or maximal exercise. Perceptual and physiological characteristics of respirators of varying inspiratory resistances should be considered by manufacturers and end users during design and respirator selection processes.