Background:Decreased physical activity (PA) influences childhood obesity and student learning. Sixty minutes (min) of daily moderate-to-vigorous physical activity (MVPA) are recommended for good health and optimized academic achievement. Methods:We quantified all-day and in-school PA in association with academic success. Cross-sectional accelerometer data from 1 115 second-twelfth graders were evaluated for daily and in-school MVPA and vigorous physical activity (VPA). Associations between PA values and year-end grade point average (GPA) in grades 6-12 and criterion referenced standardized tests in reading (CRT-R) and math (CRT-M) were examined for grades 3-8 and 11 by multivariable regression. Results:MVPA and VPA declined as student grade level increased. Higher in-school and full-day PA was associated with increased academic success (e.g., GPA and standardized testing), with the effect size increasing with advancing grade level. Accumulating 30 ​min more of in-school MVPA was associated with 0.63 higher GPA. Accumulating 10 ​min more of in-school VPA was associated with higher standardized test scores: +11.9% and +12.0% for CRT-M and CRT-R, respectively. Conclusions:Across advancing grade levels, students were on average less physically active. Habitual physical activity at every grade level was associated with higher levels of academic success based on GPA and standardized test scores in both math and reading.

Background Decreased physical activity (PA) influences childhood obesity and student learning. Sixty minutes (min) of daily moderate-to-vigorous physical activity (MVPA) are recommended for good health and optimized academic achievement. Methods We quantified all-day and in-school PA in association with academic success. Cross-sectional accelerometer data from 1115 second-twelfth graders were evaluated for daily and in-school MVPA and vigorous physical activity (VPA). Associations between PA values and year-end grade point average (GPA) in grades 6u201312 and criterion referenced standardized tests in reading (CRT-R) and math (CRT-M) were examined for grades 3u20138 and 11 by multivariable regression. Results MVPA and VPA declined as student grade level increased. Higher in-school and full-day PA was associated with increased academic success (e.g., GPA and standardized testing), with the effect size increasing with advancing grade level. Accumulating 30 min more of in-school MVPA was associated with 0.63 higher GPA. Accumulating 10 min more of in-school VPA was associated with higher standardized test scores: +11.9% and +12.0% for CRT-M and CRT-R, respectively. Conclusions Across advancing grade levels, students were on average less physically active. Habitual physical activity at every grade level was associated with higher levels of academic success based on GPA and standardized test scores in both math and reading.

ABSTRACT Purpose ACSM guidelines state that aerobic exercise intensity should be 30%/40% to 89% V̇O2reserve (V̇O2R) or heart rate reserve (HRR). Determining the proper intensity within this range is the “art” of exercise prescription, often relying on rating of perceived exertion (RPE) as the adjunctive intensity modulator. Current guidelines do not consider the use of ventilatory threshold (VT) due to the need for specialized equipment and methodological issues. The purpose of this investigation was to evaluate VT related to V̇O2peak, V̇O2R, HRR, and RPE across the full spectrum of very low to very high V̇O2peak values. Methods Eight hundred and sixty-three records of exercise tests were retrospectively examined. Data were stratified for V̇O2peak, activity level, age, test modality, and sex. Results When stratified for V̇O2peak, V̇O2 at VT (V̇O2vt) had a lower mean value of ~14 mL·kg−1·min−1 in the lowest fit, rose gradually until median V̇O2peak, and rose steeply thereafter. When graphed relative to V̇O2peak, V̇O2vt as a percentage of V̇O2R (VT%V̇O2R) resembled a U-shaped curve, with a nadir ~43% V̇O2R at V̇O2peak ~40 mL·kg−1·min−1. Average VT%V̇O2R increased to ~75% in groups with the lowest or highest V̇O2peak. There was a large variance in the value of VT at all V̇O2peak levels. Mean RPE at VT was 12.5 ± 0.93, regardless of V̇O2peak. Conclusions Given the relationship of VT as the transition from moderate- to higher-intensity exercise, these data may help the understanding of aerobic exercise prescription in persons across the spectrum of V̇O2peak values.

Hiking with a pack is the highest-intensity task that wildland firefighters (WLFFs) perform during sustained activities related to wildland fire suppression. Firefighters perform this and other tasks together as a crew; this provides a unique model to evaluate select physical and physiological changes in members of working crews over a fire season during extended operations. The objective of this study was to evaluate changes in peak aerobic fitness (VO2peak), sustainable aerobic fitness at the ventilatory threshold (VO2vt) and body composition over a 5-month wildland fire season. WLFFs from four crews (55 males, 10 females) participated in a maximal graded exercise treadmill test and body composition evaluation pre- and post season. VO2peak values and variance did not change across the fire season (pre=3.96±0.65, post=3.96±0.69Lmin−1, not significant). VO2vt average decreased slightly while variance decreased greatly within each crew (pre=37.5±7.0, post=35.4±2.3mLkg−1 min−1, P<0.05). There was an improvement in VO2vt in initially less-fit WLFFs and a VO2vt decrease in initially more-fit WLFFs. WLFFs lost fat mass (−1.56±−1.06kg, P<0.01) and fat-free mass (−0.38±−1.24kg, P<0.05). Post-season VO2vt values were the same as the higher range of the documented metabolic cost of uphill load carriage and reveal a unique group adaptation to extended physical demands.

We read “Metabolic demand of hiking in wildland firefighting” by Sol et al1Sol J.A. Ruby B.C. Gaskill S.E. Dumke C.L. Domitrovich J.W. Metabolic demand of hiking in wildland firefighting.Wilderness Environ Med. 2018; 29: 304-314Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar with great interest. As recent events in California highlight, wildfires present a major environmental threat to large portions of the population, none more so than the dedicated firefighters who combat them. Continuing research to better understand the demands of firefighting and to maximize firefighter preparedness is essential. The findings reported by Sol et al address important elements of preparation by calculating estimated metabolic demands while hiking during training exercises and actual firefighting missions and comparing these to the previously estimated demand of the arduous pack test. The authors concluded that these data could be used to further refine work capacity testing for wildland firefighters. Although we agree that these data are the most robust available, we believe a few key factors were missing from the authors’ analysis and discussion. The authors use the Pandolf equation to calculate estimated metabolic demand. Although the Pandolf equation has been validated at altitude, there is an upper limit of exercise intensity (2.1 L·min−1) after which it may not be accurate.2Cymerman A. Pandolf K.B. Young A.J. Maher J.T. Energy expenditure during load carriage at high altitude.J Appl Physiol Respir Environ Exerc Physiol. 1981; 51: 14-18PubMed Google Scholar Given an average weight of 82.9 kg among the firefighters in this study and reported energy expenditures up to 35 mL·kg−1·min−1, the Pandolf equation might not be reliable for maximal efforts at higher altitudes. Because the authors used a global positioning system to determine hiking grade and velocity, we presume that altitude data are also available, and we would be interested in further analysis on the effects of altitude on the factors reported. The impact of smoke on energy expenditure and oxygen consumption is another important difference between firefighting deployments and training exercises. Although wildland fires do not usually lead to hypoxic conditions or critical levels of carbon monoxide in the surrounding environment in light of environmental mixing of air,3Alexander M.E. Mutch R.W. Davis K.M. Bucks C.M. Wildland fires: danger and survival.in: Auerbach PS Wilderness Medicine. 6th ed. Elsevier, Philadelphia, PA2012: 240-279Google Scholar that does not mean there is no impact on respiratory functioning. Studies have shown a decrease in forced expiratory volume in 1 s (FEV1) after a single season of firefighting,4Black C. Tesfaigzi Y. Bassein J.A. Miller L.A. Wildfire smoke exposure and human health: significant gaps in research for a growing public health issue.Environ Toxicol Pharmacol. 2017; 55: 186-195Crossref PubMed Scopus (127) Google Scholar as well as increased exposure to particulate matter and carbon monoxide.5Gaughan D.M. Piacitelli C.A. Chen B.T. Law B.F. Virji M.A. Edwards N.T. et al.Exposure and cross-shift lung function declines in wildland firefighters.J Occup Environ Hyg. 2014; 11: 591-603Google Scholar Importantly, the degree of exposure varies depending on crew assignment, which was not a variable included in the current analysis. The authors state that the average energy expenditure during ingress hikes was similar to that required by the arduous pack test, but less than that demanded by training exercises. As part of the discussion, the authors posit that interagency hotshot crews may be preparing at an intensity designed to reflect the most taxing aspects of deployments.1Sol J.A. Ruby B.C. Gaskill S.E. Dumke C.L. Domitrovich J.W. Metabolic demand of hiking in wildland firefighting.Wilderness Environ Med. 2018; 29: 304-314Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar Because these deployments differ by other environmental factors, such as altitude and smoke inhalation, that may impede performance, they must be included in any thoughtful discussion of preparedness.

INTRODUCTION:The objective of this study was to document characteristics of hiking during wildland firefighter (WLFF) training and wildfire suppression. For the first time, the overall physical demands during wildland firefighting were evaluated in the field using global positioning systems coupled with wireless physiological monitoring and load carriage prediction models.METHODS:Male (n=116) and female (n=15) interagency hotshot crew and type II WLFFs on wildfires volunteered for this direct observation study. Participants' heart rate, internal temperature, speed, and elevation gain were monitored throughout training and during wildfire suppression. The Pandolf and Santee equations were used to predict metabolic rate to estimate oxygen consumption of uphill and downhill hiking.RESULTS:Equipment weight varied by crew type (type II: 24±9 kg and interagency hotshot crew: 28±6 kg; P<0.05). Grade of terrain was steepest during training hikes, and ingress hikes were statistically different from egress and training hikes (ingress: 4±9%, shift: 4±9%, egress: 1±8%, training hikes: 10±9%; P<0.01). Estimated oxygen consumption was highest during ingress hikes and was significantly different from all other hike types on fire assignments (ingress: 22±12, shift: 19±12, egress: 19±12 mL·kg-1·min-1; P=0.01). Oxygen consumption was higher during training hikes (34±14 mL·kg-1·min-1) than during job-related hikes (P<0.01).CONCLUSIONS: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.

—In many parts of the world, the combined effects of wildfire, climate change, and population growth in the wildland-urban interface pose increasing risks to both people and biodiversity. These risks are exemplified in western Oregon’s Willamette Valley Ecoregion, where population is projected to double by 2050 and climate change is expected to increase wildfire risk. Restoring elements of the region’s historic fire-adapted prairie, savanna, and woodland habitats may help to reduce future wildfire risk and help conserve the region’s threatened biodiversity. We report on a mail survey (n = 939) examining the sociodemographic factors influencing private landowners’ likelihood of restoring fire-adapted habitats in the future. We found that newer landowners, landowners with a liberal political ideology, and landowners who have experienced wildfire are more likely to restore fire-adapted habitats in the future than their long-time owner, conservative, or inexperienced counterparts. However, experience with wildfire ceased to be a significant influence when we controlled for underlying landowner motivations for owning their property. Our findings can help planners and scientists better understand and account for the effects of a dynamic human population’s influence on landscape patterns, structures, and composition.

The use of physical employment standards (PES) has helped ensure that workers have the physical attributes necessary to complete their jobs in a safe and efficient manner. However, PES used in the selection processes have not always reflected the critical physical requirements of the job tasks. Women generally have smaller anthropometric stature than men, less muscle mass, and therefore less strength, power, and endurance, particularly in the upper body. Nonetheless, these attributes in themselves are not valid grounds for exclusion from employment in physically demanding occupations. Selection standards based upon size or strength, irrespective of the job requirements, have resulted in the barring of capable women from physically demanding jobs, claims of gender bias, and costly litigations. To ensure all individuals are provided with equal access to employment, accurate characterization of the critical physical requirements of the job is paramount. This paper summarizes the existing research related to disparities between the sexes that contribute to sex differences in job performance in physically demanding occupations including physical and legal factors. Strategies for mitigating these differences in the setting of PES and the meeting of minimum employment standards are discussed. Where available, injury rates for women and men in physically demanding occupations are presented and the etiology considered. Finally, areas for further research are identified.

PurposeThe purpose of this study was to develop a lifestyle change program for Native American youth by modifying the Diabetes Prevention Program (DPP) and assess implementation indicators and short term behavioral and physiological outcomes of the intervention among a small pilot sample. MethodsCommunity members and project staff modified the original DPP to be developmentally and culturally appropriate for youth targeting healthy weight maintenance, lowering fat intake, and increasing physical activity. Modifications included incorporating cultural aspects and delivering the program in small groups led by community members. Sixty-four Native American youth, aged 10-14 years old were recruited from 2 Montana Indian reservations to participate in the project, titled “Journey to Native Youth Health.” Participants were randomized to the Journey DPP or a health-oriented comparison condition. Pretest and posttest measures included body mass index (BMI), dietary intake, physical activity (PA), and nutrition knowledge, attitudes and beliefs (KAB). ResultsThe target number of participants was recruited and 84% completed the program and final measures. Changes favoring the Journey DPP group were observed on measures of PA, KAB, and kilocalories from fat consumed. As expected given the short (3-month) duration of treatment, there was no overall effect on BMI at end of treatment. Among youth who were overweight or obese at baseline, however, the Journey DPP had lower BMI growth. ConclusionsResults suggest the Journey DPP is feasible to implement and has the potential to impact behaviors and weight gain associated with risk for type-2 diabetes in Native American youth.

Wildland fire base camps commonly house thousands of support personnel for weeks at a time. The selection of the location of these base camps is largely a strategic decision that incorporates many factors, one of which is the potential impact of biomass smoke from the nearby fire event. Biomass smoke has many documented adverse health effects due, primarily, to high levels of fine particulate matter (PM(2.5)). Minimizing particulate matter exposure to potentially susceptible individuals working as support personnel in the base camp is vital. In addition to smoke from nearby wildland fires, base camp operations have the potential to generate particulate matter via vehicle emissions, dust, and generator use. We monitored particulate matter at three base camps during the fire season of 2009 in Washington, Oregon, and California. During the sampling events, 1-min time-weighted averages of PM(2.5) and particle counts from three size fractions (0.3-0.5 microns, 0.5-1.0 microns, and 1.0-2.5 microns) were measured. Results showed that all PM size fractions (as well as overall PM(2.5) concentrations) were higher during the overnight hours, a trend that was consistent at all camps. Our results provide evidence of camp-based, site-specific sources of PM(2.5) that could potentially exceed the contributions from the nearby wildfire. These exposures could adversely impact wildland firefighters who sleep in the camp, as well as the camp support personnel, who could include susceptible individuals. A better understanding of the sources and patterns of poor air quality within base camps would help to inform prevention strategies to reduce personnel exposures.

PURPOSE: To determine the ability of the current smokejumper physical fitness tests to predict performance on smokejumper job specific tasks. METHODS:A total of 57 wildland firefighters (38 smokejumpers, 19 non-smokejumper wildland firefighters) completed testing. Laboratory measures included body composition, and VO2 peak. The physical training (PT) tests were maximum continuous repetitions for sit-ups, push-ups, pull-ups, and time for a 1.5 mile run. Job specific field tasks were line digging (12 inch wide line to mineral soil with a Pulaski tool), pack carry (3 miles on mountainous terrain with 85 lbs), and lifting/carrying (movement of as many 45 lbs water containers for 10 meters in 5 min). Multiple regression analysis was used to correlate the PT test to job specific tasks. Data is reported as mean ± SD. Significance was set at α = 0.05. RESULTS: Subject descriptive data: age (29.67 ± 7.32 yrs), height (178.9 ± 8.16 cm), weight (77.26 ± 11.24 kg), VO2 peak (55.54 ± 6.47 ml · kg-1 · min-1). PT test RESULTS: sit-ups (119 ± 45), push-ups (53 ± 22), pull-ups (13 ± 7) and the 1.5 mile run (7.78 ± 0.74 min). The current PT test had significant multiple correlations with line digging (r = 0.634, adj r2 = 0.341; p < 0.05), pack outs (r = 0.648, adj r2 = 0.357; p < 0.05) and lifting/carrying (r = 0.818, adj r2 = 0.644; p < 0.05). There were no differences between the heaviest and lightest individuals on PT test scores. CONCLUSIONS:The U.S. smokejumper PT test is a valid testing procedure based on The Uniform Guidelines on Employee Selection.

Carbon Monoxide (CO) is known to be a potentially deadly gas. Headaches may occur at 5%-10% carboxyhemoglobin (COHb) saturation. Symptoms and dysfunction increase to 60% COHb saturation where coma and death are likely. Wildland firefighters (WLFF) are often exposed to CO in wildland fire smoke, from vehicle engine exhaust, generator exhaust, volatile fuels and small engines such as water pumps. PURPOSE: The purpose of this project was to obtain preliminary data on carboxyhemoglobin levels in WLFFs. METHODS: COHb was measured in 408 WLFF who reported either working in some smoke or near engine sources of CO. COHb data were collected both during wildland fire suppression and in fire camps. Information collected included duration and time of smoke exposure, "intensity" of smoke, cigarette smoking status and WLFF job. COHb data were corrected to a standard half life of 5 hours for measurements made post shift. RESULTS: WLFF who worked >10 hours in smoke had higher COHb levels than WLFF with shorter smoke exposures (4.3±4.7% vs. 2.5±1.9%, p<0.05). Workers who reported being near generators had higher COHb values (5.2±3.4%, p<0.05) than those working in wildfire smoke (2.6±2.0%) or those working near diesel trucks (2.2±1.8%). Working in heavy smoke resulted in higher COHb saturation than working in light smoke (5.2±4.8% vs. 2.8±1.9%, p<0.01). Field work around generators and diesel trucks resulted in modest COHb (2.7±2.1%) but Mark 4 pump operators had higher (p<0.05) COHb (6.2±3.0%). Only 6 of 408 individuals exceeded 10% COHb saturation. Smokers had overall higher levels of COHb than non smokers (3.8±2.5% vs. 2.3±1.6%, p<0.05). CONCLUSIONS: WLFF averaged modest COHb saturation levels from wildfire smoke or engines but few were found to exceed even 10% COHb saturation. However, there is evidence that chronic low level CO exposure may have lasting health effects. The evidence from these data is inconclusive to state that CO exposure is a major problem in WLFF. However smoke conditions during the period of study were not extreme with only 12 subjects reporting working in heavy smoke for extended periods. We suggest further study to evaluate COHb saturation during extended work in heavy smoke as well as the cumulative effect that both tobacco smoking and firefighting might have on WLFF. (Values are COHb saturation ± std. deviation).