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Background: Circulating heat-inducible, heat-shock protein 72 [HSP72] responses to exercise-heat stress have been well studied as a potential biomarker of exertional heat illness susceptibility. However, little is known about the responses of other HSPs important to immune responses and pathophysiology. HSP27, -60, and -90 are fundamental HSPs important in cellular proteostasis and pathophysiology associated with immune dysregulation. Therefore, we aimed to characterize responses of HSP27, -60, and –90 during a race known to introduce extreme levels of exercise-heat stress that annually result in high incidences of exertional heat stroke. Methods: Thirty participants (45.3±11.7 yr, 175.6±8.9 cm, 74.9±13.5 kg, 19.7±3.6 % body fat) registered to run in the Falmouth Road Race (Falmouth, MA) were recruited. Gastrointestinal temperature (TGI) and blood plasma HSP27, -60, and -90 (by commercially available ELISA) were measured at pre- (PRE) and post-race (POST). Results: TGI, [HSP27], and [HSP90] increased at POST (pGI at POST (p>0.05). In conclusion, HSPs are important for constitutive cellular function and measurably increase circulation post-exercise-heat stress. Correlation between HSPs and pre- or post-event core temperature to determine utility as predictive biomarkers require further study.

Context The use of aural thermometry as a method for accurately measuring internal temperature has been questioned. No researchers have examined whether aural thermometry can accurately measure internal body temperature in patients with exertional heat stroke (EHS). Objective To examine the effectiveness of aural thermometry as an alternative to the criterion standard of rectal thermometry in patients with and those without EHS. Design Cross-sectional study. Setting An 11.3-km road race. Patients or Other Participants A total of 49 patients with EHS (15 men [age = 38 ± 17 years], 11 women [age = 28 ± 10 years]) and 23 individuals without EHS (10 men [age = 62 ± 17 years], 13 women [age = 45 ± 14 years]) who were triaged to the finish-line medical tent for suspected EHS. Main Outcome Measure(s) Rectal and aural temperatures were obtained on arrival at the medical tent for patients with and those without EHS and at 8.3 ± 5.2 minutes into EHS treatment (cold-water immersion) for patients with EHS. Results The mean difference between temperatures measured using rectal and aural thermometers in patients with EHS at medical tent admission was 2.4°C ± 0.96°C (4.3°F ± 1.7°F; mean rectal temperature = 41.1°C ± 0.8°C [106.1°F ± 1.4°F]; mean aural temperature = 38.8°C ± 1.1°C [101.8°F ± 2.0°F]). Rectal and aural temperatures during cold-water immersion in patients with EHS were 40.4°C ± 1.0°C (104.6°F ± 1.8°F) and 38.0°C ± 1.2°C (100.3°F ± 2.2°F), respectively. Rectal and aural temperatures for patients without EHS at medical tent admission were 38.8°C ± 0.87°C (101.9°F ± 1.6°F) and 37.2°C ± 1.0°C (99.1°F ± 1.8°F), respectively. Conclusions Aural thermometry is not an accurate method of diagnosing EHS and should not be used as an alternative to rectal thermometry. Using aural thermometry to diagnosis EHS can result in catastrophic outcomes, such as long-term sequelae or fatality.

Objective First, we will update recommendations for the prehospital management and care of patients with exertional heat stroke (EHS) in the secondary school setting. Second, we provide action items to aid clinicians in developing best-practice documents and policies for EHS. Third, we supply practical strategies clinicians can use to implement best practice for EHS in the secondary school setting. Data Sources An interdisciplinary working group of scientists, physicians, and athletic trainers evaluated the current literature regarding the prehospital care of EHS patients in secondary schools and developed this narrative review. When published research was nonexistent, expert opinion and experience guided the development of recommendations for implementing life-saving strategies. The group evaluated and further refined the action-oriented recommendations using the Delphi method. Conclusions Exertional heat stroke continues to be a leading cause of sudden death in young athletes and the physically active. This may be partly due to the numerous barriers and misconceptions about the best practice for diagnosing and treating patients with EHS. Exertional heat stroke is survivable if it is recognized early and appropriate measures are taken before patients are transported to hospitals for advanced medical care. Specifically, best practice for EHS evaluation and treatment includes early recognition of athletes with potential EHS, a rectal temperature measurement to confirm EHS, and cold-water immersion before transport to a hospital. With planning, communication, and persistence, clinicians can adopt these best-practice recommendations to aid in the recognition and treatment of patients with EHS in the secondary school setting.

Context Sex, age, and wet-bulb globe temperature (WBGT) have been proposed risk factors for exertional heat stroke (EHS) despite conflicting laboratory and epidemiologic evidence. Objective To examine differences in EHS incidence while accounting for sex, age, and environmental conditions. Design Observational study. Setting Falmouth Road Race, a warm-weather 7-mi (11.26-km) running road race. Patients or Other Participants We reviewed records from patients treated for EHS at medical tents. Main Outcome Measure(s) The relative risk (RR) of EHS between sexes and across ages was assessed with males as the reference population. Multivariate linear regression analyses were calculated to determine the relative contribution of sex, age, and WBGT to the incidence of EHS. Results Among 343 EHS cases, the female risk of EHS was lower overall (RR = 0.71; 95% confidence interval [CI] = 0.58, 0.89; P = .002) and for age groups 40 to 49 years (RR = 0.43; 95% CI = 0.24, 0.77; P = .005) and 50 to 59 years (RR = 0.31; 95% CI = 0.13, 0.72; P = .005). The incidence of EHS did not differ between sexes in relation to WBGT (P > .05). When sex, age, and WBGT were considered in combination, only age groups Conclusions In this unique investigation of EHS incidence in a road race, we found a 29% decreased EHS risk in females compared with males. However, when sex was considered with age and WBGT, only younger age accounted for an increased incidence of EHS. These results suggest that road race medical organizers should consider participant demographics when organizing the personnel and resources needed to treat patients with EHS. Specifically, organizers of events with greater numbers of young runners (aged 19 to 39 years) and males should prioritize ensuring that medical personnel are adequately prepared to handle patients with EHS.

CONTEXT: Sex, age, and wet-bulb globe temperature (WBGT) have been proposed risk factors for exertional heat stroke (EHS) despite conflicting laboratory and epidemiologic evidence. OBJECTIVE: To examine differences in EHS incidence while accounting for sex, age, and environmental conditions. DESIGN: Observational study. SETTING: Falmouth Road Race, a warm-weather 7-mi (11.26-km) running road race. PATIENTS OR OTHER PARTICIPANTS: We reviewed records from patients treated for EHS at medical tents. MAIN OUTCOME MEASURE(S): The relative risk (RR) of EHS between sexes and across ages was assessed with males as the reference population. Multivariate linear regression analyses were calculated to determine the relative contribution of sex, age, and WBGT to the incidence of EHS. RESULTS: Among 343 EHS cases, the female risk of EHS was lower overall (RR = 0.71; 95% confidence interval [CI] = 0.58, 0.89; P = .002) and for age groups 40 to 49 years (RR = 0.43; 95% CI = 0.24, 0.77; P = .005) and 50 to 59 years (RR = 0.31; 95% CI = 0.13, 0.72; P = .005). The incidence of EHS did not differ between sexes in relation to WBGT (P > .05). When sex, age, and WBGT were considered in combination, only age groups

The purpose of this consensus document was to develop feasible, evidence‐based occupational heat safety recommendations to protect the US workers that experience heat stress. Heat safety recommendations were created to protect worker health and to avoid productivity losses associated with occupational heat stress. Recommendations were tailored to be utilized by safety managers, industrial hygienists, and the employers who bear responsibility for implementing heat safety plans. An interdisciplinary roundtable comprised of 51 experts was assembled to create a narrative review summarizing current data and gaps in knowledge within eight heat safety topics: (a) heat hygiene, (b) hydration, (c) heat acclimatization, (d) environmental monitoring, (e) physiological monitoring, (f) body cooling, (g) textiles and personal protective gear, and (h) emergency action plan implementation. The consensus‐based recommendations for each topic were created using the Delphi method and evaluated based on scientific evidence, feasibility, and clarity. The current document presents 40 occupational heat safety recommendations across all eight topics. Establishing these recommendations will help organizations and employers create effective heat safety plans for their workplaces, address factors that limit the implementation of heat safety best‐practices and protect worker health and productivity., Key Points This document presents feasible, evidenced‐based occupational heat safety recommendations to protect workers from the dangers of heatA roundtable of 51 experts created 40 heat safety recommendations within eight heat safety topics: heat hygiene, hydration, heat acclimatization, environmental monitoring, physiological monitoring, body cooling, textiles and personal protective gear, and emergency action plan implementationImplementing feasible and effective heat safety plans in the workplace will protect worker health and mitigate productivity losses

Component graphs $\Gamma_{0}(F)$ are defined for arrays of sets $F$, and in particular for arrays of path components for Vietoris-Rips complexes and Lesnick complexes. The path components of $\Gamma_{0}(F)$ are the {\it stable components} of the array $F$. The stable components for the system of Lesnick complexes $\{ L_{s,k}(X) \}$ for a finite data set $X$ decompose into layers, which are themselves path components of a graph. Combinatorial scoring functions are defined for layers and stable components., Comment: 17 pages, 1 figure

Exertional heat illness (EHI) risk is a serious concern among athletes, laborers, and warfighters. US Governing organizations have established various activity modification guidelines (AMGs) and other risk mitigation plans to help ensure the health and safety of their workers. The extent of metabolic heat production and heat gain that ensue from their work are the core reasons for EHI in the aforementioned population. Therefore, the major focus of AMGs in all settings is to modulate the work intensity and duration with additional modification in adjustable extrinsic risk factors (e.g., clothing, equipment) and intrinsic risk factors (e.g., heat acclimatization, fitness, hydration status). Future studies should continue to integrate more physiological (e.g., valid body fluid balance, internal body temperature) and biometeorological factors (e.g., cumulative heat stress) to the existing heat risk assessment models to reduce the assumptions and limitations in them. Future interagency collaboration to advance heat mitigation plans among physically active population is desired to maximize the existing resources and data to facilitate advancement in AMGs for environmental heat.

This paper gives an introduction to homotopy descent, and its applications in algebraic $K$-theory computations for fields. On the etale site of a field, a fibrant model of a simplicial presheaf can be constructed from naive Galois cohomological objects given by homotopy fixed point constructions, but only up to pro-equivalence. The homotopy fixed point spaces define finite Galois descent for simplicial presheaves (and their relatives) over a field, but a pro-categorical construction is a necessary second step for passage from finite descent conditions to full homotopy descent in a Galois cohomological setting.

On-site medical care should be considered essential for mass participation athletic events. Events such as road races, marathons, and triathlons may attract thousands of participants and spectators, which may overwhelm regional health care capabilities. One successful model of a mass participation event medical care system involves direction by a medical director or coordinator who is a physician and is ideally trained in emergency and/or sports medicine.

Exertional heat illness (EHI) is a cause for concern in athletic, military, occupational, and recreational settings where individuals are participating in physical activity, especially in hot environmental conditions. EHI includes a spectrum of medical conditions that range from non-life-threatening, such as heat syncope, to potentially fatal in the case of exertional heat stroke. Given the severity of the latter condition, it is prudent for clinicians providing medical care in the aforementioned settings to develop evidence-based protocols for the prevention, recognition, treatment and return to activity for each of the medical conditions falling under the classification of EHI. The aim of this chapter is to provide an overview of the classification and nomenclature of EHI, particularly the specific conditions contained within this general domain. We will discuss the current incidence and epidemiology of EHI to provide additional context surrounding the content covered within this text.

The New Balance Falmouth Road Race held in Falmouth, Massachusetts, U.S. is a short distance race (11.26 km) that is well-known for high rates of exertional heat stroke (EHS). Previous research has documented the increased EHS rates with hotter and more humid weather conditions, yet did not explore the influence of race pacing on EHS risk. In this study, we leverage 15 years of data to investigate if runners who experienced an EHS moderate their average paces based on weather conditions and if there is a difference in average race pace between participants who experienced an EHS and other runners. Results indicate that runners who experience an EHS do not appear to reduce their average pace with increasing WBGT warning flag categories. In addition, runners who suffer an EHS run at a faster average pace than others, even when controlling for age, gender, race performance, and starting time WBGT. This suggests the important role of metabolic heat production as a risk factor of EHS. Since race pacing is a modifiable risk factor, our findings support the need for race organizers to actively encourage runners to adjust race pacing based on weather conditions.

Context Little is known about how educating runners may correct common misconceptions surrounding heat safety and hydration strategies. Objective To investigate (1) beliefs and knowledge about heat safety and hydration strategies among recreational runners and (2) the effectiveness of an educational video in optimizing performance in the heat. Design Cross-sectional study. Setting Survey. Patients or Other Participants A total of 2091 (25.1%) of 8319 runners registered for the 2017 Falmouth Road Race completed at least 1 of the 3 administered surveys. Intervention(s) A 5.3-minute video and an 11-question survey regarding heat safety and hydration strategies were developed, validated, and implemented. The survey was e-mailed to registrants 9 weeks before the race (PRERACE), after they viewed the video (POSTEDU), and the afternoon of the race (POSTRACE). Main Outcome Measure(s) The total score for responses to 2 multiple choice questions and nine 5-point (response range = strongly agree to strongly disagree) Likert-scale questions. Results The PRERACE results showed that more than 90% of respondents recognized the importance of staying hydrated beginning the day before the planned activity, correctly identified that dark color urine is not a sign of euhydration, and believed that dehydration may increase the risk for heat syncope. Conversely, fewer than 50% of respondents knew the number of days required to achieve heat acclimatization, the role of sweat-rate calculation in optimizing one's hydration strategy, or the risk of water intoxication from drinking too much water. An improvement in survey score from PRERACE to POSTEDU was observed (mean difference = 2.00; 95% confidence interval = 1.68, 2.33; P < .001) among runners who watched the video, and 73% of the improvement in their scores was retained from POSTEDU to POSTRACE (mean difference = −0.54; 95% confidence interval = −0.86, −0.21; P < .001). Conclusions The video successfully shifted runners' beliefs and knowledge to enable them to better optimize their performance in the heat.

Exertional heat stroke (EHS) is one of the most common causes of sudden death in athletes. It also represents a unique medical challenge to the prehospital healthcare provider due to the time sensitive nature of treatment. In cases of EHS, when cooling is delayed, there is a significant increase in organ damage, morbidity, and mortality after 30 minutes, faster than the average EMS transport and ED evaluation window. The purpose of this document is to present a paradigm for prehospital healthcare systems to minimize the risk of morbidity and mortality for EHS patients. With proper planning, EHS can be managed successfully by the prehospital healthcare provider.

Exercising in hot, humid environments can have a negative impact on exercise performance and one’s health. Strategies such as gradually becoming accustomed to exercise in new environments, adequate hydration and nutrition, and appropriate work-to-rest ratios can help decrease the risk of exertional heat illness. If an exertional heat illness does occur, it is imperative to rapidly recognize the condition and provide appropriate treatment. Rapid recognition and rapid cooling are essential for survival in cases of exertional heat stroke, which can be fatal. Determining the cause of the heat illness is key to ensure the athlete can safely return to exercise following the heat illness.

This document is intended to serve as a call to action for all youth sport NGBs to provide support systems for member organizations through the education of league leaders and their members on the current policy and procedure best practices regarding EAPs, SCA, brain and neck injury, EHS, and other potentially threatening medical conditions (Appendix B). This document also discusses preexisting medical conditions, environmental conditions, and emergency medical care, such as athletic training services. The Task Force recognizes that each organization is unique and, therefore, will need to address policy and procedure recommendations differently to ensure the implementation of best practices. Furthermore, the Task Force recognizes that all best-practice policy and procedure recommendations may not be necessary for each sport (eg, lightning policy for indoor sports). Many of the deaths in youth sports are preventable, and it is the goal of the Task Force to support youth sport NGBs in this mission of prevention.

Context: Recent case reports on malignant hyperthermia (MH)-like syndrome in physically active populations indicate potential associations among MH, exertional heat stroke (EHS), and exertional rhabdomyolysis (ER). However, an expert consensus for clinicians working with these populations is lacking. Objective: To provide current expert consensus on the (1) definition of MH; (2) history, etiology, and pathophysiology of MH; (3) epidemiology of MH; (4) association of MH with EHS and ER; (5) identification of an MH-like syndrome; (6) recommendations for acute management of an MH-like syndrome; (7) special considerations for physically active populations; and (8) future directions for research. Setting: An interassociation task force was formed by experts in athletic training, exercise science, anesthesiology, and emergency medicine. The “Round Table on Malignant Hyperthermia in Physically Active Populations” was convened at the University of Connecticut, Storrs, September 17–18, 2015. Conclusions: Clinicians should consider an MH-like syndrome when a diagnosis of EHS or ER cannot be fully explained by clinical signs and symptoms presented by a patient or when recurrent episodes of EHS or ER (or both) are unexplained. Further research is required to elucidate the genetic and pathophysiological links among MH, EHS, and ER.

Standard results from non-abelian cohomology theory specialize to a theory of torsors and stacks for cosimplicial groupoids. The space of global sections of the stack completion of a cosimplicial groupoid $G$ is weakly equivalent to the Bousfield–Kan total complex of $BG$ for all cosimplicial groupoids $G$. The $k$-invariants for the Postnikov tower of a cosimplicial space $X$ are naturally elements of stack cohomology for the stack associated to the fundamental groupoid ${\it\pi}(X)$ of $X$. Cocycle-theoretic ideas and techniques are used throughout the paper.

This note gives a simple cocycle-theoretic proof of the Verdier hypercovering theorem. This theorem approximates morphisms [X,Y ] in the homotopy category of simplicial sheaves or presheaves by simplicial homotopy classes of maps, in the case where Y is locally fibrant. The statement proved in this paper is a generalization of the standard Verdier hypercovering result in that it is pointed (in a very broad sense) and there is no requirement for the source object X to be locally fibrant. Mathematics Department, University of Western Ontario, London, ON N6A 5B7 e-mail: jardine@uwo.ca Received by the editors May 11, 2009; revised December 2, 2009. Published electronically May 17, 2011. AMS subject classification: 14F35, 18G30, 55U35.

This paper displays model structures for the category of pro-objects in simplicial presheaves on an arbitrary small Grothendieck site. The first of these is an analogue of the Edwards-Hastings model structure for pro-simplicial sets, in which the cofibrations are monomorphisms and the weak equivalences are specified by comparisons of function complexes. Other model structures are built from the Edwards-Hastings structure by using Bousfield-Friedlander localization techniques. There is, in particular, an n-type structure for pro-simplicial presheaves, and also a model structure in which the map from a pro-object to its Postnikov tower is formally inverted.

Suppose that M is a simplicial model category and that F is a contravariant simplicial functor defined on M which takes values in pointed simplicial sets. This note displays conditions on the simplicial model category M and the functor F such that F is representable up to weak equivalence. The conditions on F are homotopy coherent versions of the classical conditions for Brown representability, while M should have the fundamental properties of the stable model structure for presheaves of spectra on a Grothendieck site.

Path categories are defined, and their basic properties are described, for simplicial and cubical sets. A calculational method for describing the path category P(K) of a finite oriented simplicial complex K is introduced, which involves a finite 2-category which can be specified by generators and relations. This method specializes to higher dimensional automata via the triangulation functor from cubical to simplicial sets, and leads to calculations of their associated execution paths.

This note shows that any set of cofibrations containing the standard set of generating projective cofibrations determines a cofibrantly generated proper closed model structure on the category of simplicial presheaves on a small Grothendieck site, for which the weak equivalences are the local weak equivalences in the usual sense.

The usual notion of the site associated to a stack is expanded to a definition to a site \(\mathcal{C}/A\) fibred over a presheaf of categories A on a site \(\mathcal{C}\). If the presheaf of categories is a presheaf of groupoids G, then the associated homotopy theory is Quillen equivalant to the homotopy theory of simplicial presheaves over BG, and so the homotopy theory for the fibred site \(\mathcal{C}/G\) is an invariant of the homotopy type of G. Similar homotopy invariance results obtain for presheaves of spectra and presheaves of symmetric spectra on \(\mathcal{C}/G\). In particular, stack cohomology can be calculated on the fibred site for any representing presheaf of groupoids within a fixed homotopy type.

It is shown that the groupoid of G-torsors, suitably defined, can be used to construct a model for the stack associated to G, for arbitrary sheaves of groupoids G.

This paper is an exposition of the ideas and methods of Cisinksi, in the context of A-presheaves on a small Grothendieck site, where A is an arbitrary test category in the sense of Grothendieck. The homotopy theory for the category of simplicial presheaves and each of its localizations can be modelled by A-presheaves in the sense that there is a corresponding model structure for A-presheaves with an equivalent homotopy category. The theory specializes, for example, to the homotopy theories of cubical sets and cubical presheaves, and gives a cubical model for motivic homotopy theory. The applications of Cisinski’s ideas are explained in some detail for cubical sets.

Suppose that G is a group scheme which is finite and etale over a Noetherian scheme S. The main result of this paper asserts the existence of a bijection between the sets of isomorphism classes of qfh and etale torsors over S with coefficients in G.

Presheaves of spectra have been in use for some time. The original applications were in algebraic K -theory, but they now appear in various other areas. A simple existence proof for the stable model structure for presheaves of spectra appears in the first section of this chapter.

The injective model structure for simplicial presheaves induces model structures on the categories of presheaves of -groupoids, presheaves of 2 groupoids and presheaves of groupoids enriched in simplicial sets. The corresponding injective fibrant objects are stacks, 2-stacks and higher stacks, respectively, and the fibrant model construction is a candidate for stack replacement in each case.

Local weak equivalences and the theory of local fibrations are the subjects of this chapter. Most naively, a local weak equivalence is a map of simplicial presheaves which induces isomorphisms in all possible sheaves of homotopy groups. A local fibration is a map which has a suitably defined local right lifting property with respect to all inclusions of horns in simplices. It is fundamental result that a map is both a local weak equivalence and a local fibration if and only if it is a hypercover in the sense that it has the local right lifting property with respect all inclusions of boundaries in simplices. Hypercovers first appeared in the literature, with the birth of etale homotopy theory, as high order generalizations of Cech resolutions.

This chapter contains a brief description of the homotopy theory of simplicial sets, and the homotopy theory of diagrams of simplicial sets. This is done to establish notation, and to recall some basic constructions and well-known lines of argument. The argument for the existence of the usual model structure for simplicial sets is sketched, using a somewhat non-standard method that had its origins in Cisinski’s thesis.

The injective model structure for simplicial presheaves induces a model structure on the categories of presheaves of simplicial abelian groups and chain complexes, defined so that the underlying simplicial presheaf functor and the free abelian functor form a Quillen adjunction. This is the setting for the homotopy theoretic approach to sheaf cohomology theory and hypercohomology, and their classifications as morphisms in the homotopy category of simplicial presheaves.

This chapter is a rapid introduction to the geometric flavour of topos theory that is used thoughout the book. A Grothendieck topology is a formal calculus of coverings which generalizes the algebra of open covers of a topological space, and can exist in much more generality.