Content uploaded by Michael N Sawka
Author content
All content in this area was uploaded by Michael N Sawka on Jun 12, 2015
Content may be subject to copyright.
Prevention and Management of Cold-Weather Injuries
Abstract
Soldiers participating in military deployments often encounter cold Stress that requires management for successful mission accomplishment. Excessive cold stress degrades physical performance capabilities, significantly impacts morale, and eventually causes cold casualties. Cold stress environments include not only exposure to extremely low temperatures, but also cold-wet exposures in warmer ambient temperatures. The purpose of this bulletin is to provide guidance to military and civilian health care providers, allied medical personnel, and unit commanders and leaders to develop an evidence-based prevention program to protect military personnel from cold stress and associated adverse health effects. The TB MED will enable individuals to: 1) understand the physiologic responses and adaptations to cold, 2) implement procedures for managing cold stress, 3) understand the principles and proper use of cold weather clothing, 4) understand the diagnosis and treatment of nonfreezing and freezing cold injuries and other medical conditions associated with cold weather, 5) identify the risk factors for cold injuries and implement treatment, and 6) prevent cold injuries during deployment and training.
... This limited vapor transfer ultimately reduces the insulative properties of the PPE, increasing the risk of hypothermia during subsequent periods of reduced physical activity or rest. Several injuries can occur due to excessive exposure to cold stress including freezing (when skin temperature falls below freezing) and non-freezing (when the skin remains cold and wet for an extended duration) cold injuries [154]. Eventually, if core temperature decreases below 35 • C because heat loss exceeds heat production, hypothermia will occur. ...
Firefighters are exposed to many dangerous and stressful situations when they are deployed to fight structural and wildland fires as well as rescuing victims from vehicular accidents, or other adverse events. When they are deployed, they can be exposed to physical danger as well as extreme heat and/or extreme cold due to fire and environmental conditions, thus making firefighting an extreme environment. This chapter provides an overview of the firefighter profession as an extreme environment including their clothing and equipment, the specific impacts on the human body, and the impact of biological sex and gender together with training and fitness approaches. This situational context information is important in order to understand this profession and the opportunities for engineering and information technology solutions for health, wellness, resilience, and adaption within this population.
... For example, cold stress is known to cause specific physiological, psychological, and behavioral responses configured to maintain performance or wholly avoid cold environments. Cold exposure severity is dependent on ambient temperature, exposure medium (air, water), velocity (wind, water movement), duration, exposed surface area (partial or whole-body), degree of thermal protection, and psychological state (anxious, fatigued, injured) of the individual being exposed (Castellani et al., 2005;Castellani & Young, 2016;Henriksson et al., 2009). Changes to any of these elements can drastically alter physiology and performance. ...
Human cognition unfolds in a multitude of environments, including those that are associated with extreme stressors. Successfully measuring and modeling behaviors in such environments is inherently difficult. The current effort aimed to assess variation in stability and flexibility of cognitive performance during cold stress, individual differences in errors, and physiological correlates. Fifty-seven service members completed cold water immersion during winter months. Individuals were required to immerse themselves in an outdoor pond for 10 minutes, reclothe into dry clothing, and attempt to rewarm. Simple reaction time and match-to-sample tasks were completed throughout the 90 minute procedure. To assess response stability , sample entropy was computed for the response time time-series of each task. Hierarchical clustering applied to sample entropy values identified two clusters of individuals. One highly affected group demonstrated low stability and weak flexibility by way of higher autocorrelation and more omission errors, and had lower hand temperature pre-and post-immersion. Results are discussed within the context of cold stress, adaptive behaviors, and cold stress.
... Although the influence of nonshivering thermogenesis may have beneficial implications with respect to weight loss (31), the combination of chronic physical exertion and cold exposure could lead to sustained periods of negative caloric balance. Preservation of lean body mass may be stressed and diminish physiological resilience for military and/or emergency personnel who operate under such conditions (8,16,21,29). To understand the potential significance of these factors, physiological responses in a dynamic field setting must be directly measured under such arduous conditions (5,11,17). ...
Purpose
The Yukon Arctic Ultra is considered the longest and coldest ultraendurance event in the world. Cold exposure and exercise has been reported to influence circulating levels of myokines, adipokines, and hepatokines that may influence considerable alterations in the regulation of metabolism. The purpose of the study was to evaluate the influence of the Yukon Arctic Ultra (430-mile event) on potential activators of brown fat, metabolites, and body composition in healthy individuals.
Methods
Eight male and female participants (mean ± SEM: age, 44 ± 3 yr; body mass index, 23.4 ± 0.9) were recruited for participation. Blood samples were collected at pre-event, mid-event, and post-event checkpoints.
Results
The temperature during the event ranged from −45°C to −8°C. Because of these extremely challenging conditions, 50% of the participants withdrew from competition by the 300-mile mark, and those that surpassed 300 miles lost a significant (P = 0.002; P = 0.01) amount of body weight (76 ± 5 kg to 73 ± 4 kg) and fat mass (13 ± 1 kg to 12 ± 3 kg), respectively. With respect to serum irisin, there was a trend (P = 0.06) toward significance from pre-event (1033 ± 88 ng·mL⁻¹), mid-event (1265 ± 23 ng·mL⁻¹) to post-event (1289 ± 24 ng·mL⁻¹). Serum meteorin-like and fibroblast growth factor-21 remained stable throughout the event. There were no changes in creatinine, acetoacetate, acetate, and valine. Serum lactate decreased (P = 0.04) during the event.
Conclusions
The influence of cold exposure and extreme physical exertion may promote substantial increases in serum irisin, and specific alterations in substrate metabolism that largely preserve skeletal muscle and physiological resilience.
... logy. J Musculoskelet Neuronal Interact, 4(2): 159-160. [32] Roos, M.R., Rice, C.L., Connelly, D.M. and Vandervoort, A.A. [35] Samson, M.M., Meeuwsen, I.B., Crowe, A., Dessens, J.A., Duursma, S.A. and Verhaar, H.J. (2000). Relationships between physical performance measures, age, height and body weight in healthy adults. Age Ageing, 29(3): 235-242. [36] Shephard, R.J. (1999). Age and physical work capacity. Exp Aging Res, 25(4): 331-343. [37] Sjödin, B. and Svedenhag, J. (1985). Applied physiology of marathon running. Sports Med, 2(2): 83-99. [38] Sleivert, G.G. and Rowlands, D.S. (1996). Physical and physiological factors associated with success in the triathlon. Sports Med, 22(1): 8- ...
Age is widely regarded as the most important determinant of the loss of an individual's physical performance capability over time. Said loss is of concern for employers of personnel involved in physically demanding occupations, particularly military personnel. A minimum level of physical performance is a prerequisite for military personnel because the absolute physical job demands are often dictated by extrinsic factors that cannot be altered. A reduced work capacity may lead to inadequate performance, increase the risk of overuse injury, and, ultimately, compromise effectiveness of military operations. However, appropriate training can counter the effects of aging on strength and endurance and enable the individual to maintain adequate levels of performance late into life.
Athlete injuries are a pervasive issue in sports, resulting in significant consequences for athletic performance, career longevity, and overall well-being. To address this challenge, we developed a predictive modeling framework that leverages machine learning techniques to identify athletes at high risk of injury. Our approach integrates a range of athlete-specific data, including demographic, training, and performance metrics, to generate personalized injury risk profiles. A random forest classifier was employed to identify key predictors and classify athletes into high-or low-risk categories. Our results demonstrate a substantial improvement in injury prediction accuracy compared to traditional methods, highlighting the potential of machine learning in athlete injury prevention. This framework has important implications for coaches, trainers, and medical professionals, enabling targeted interventions and optimized athlete performance. Our study contributes to the growing body of research in sports analytics and machine learning, underscoring the importance of data-driven approaches in promoting athlete health and performance.
Decompression illness and decompression sickness are pathologies mostly associated with diving incidents, which result from excessive bubble formation from dissolved gas. Great efforts are undertaken to perform research to understand the pathology and fundamental mechanisms, which result from the dynamic effects of compression and decompression. In this chapter, the clinical manifestation of decompression illness including the impact on different physiological systems is presented. Principles in physics, chemistry and biology are investigated that build the base to understand the mechanisms of decompression and bubble kinetics. These principles are then used to derive algorithms and concepts to calculate decompression schedules, which aim to safely step the diver back to the surface. Different approaches are dissected for their general ideas and implementation.
Persons exercising in cold weather can incur substantial fluid losses and are advised to maintain hydration to sustain performance. Body water deficits or hypohydration (HYP) in excess of 2% body mass impairs endurance exercise performance in hot and temperate environments and HYP may also degrade cognitive performance in hot-temperature conditions. However the extent to which these performance decrements occur in cold environments with HYP is unknown. This study investigated whether HYP degrades physical and cognitive performance during cold exposure and if physical exercise could mitigate any cold-induced cognitive performance decline. On four occasions, eight volunteers (6 men, 2 women) were exposed to 3 h of passive heat stress, with or without fluid replacement. Later in the day, volunteers sat in a cold or temperate environment for 1 hour before performing 30 min of cycle ergometry followed immediately by a 30-min performance time trial. Performance was assessed by the total amount of work completed during the 30-min performance time trial.
The United States Army Research Institute of Environmental Medicine (USARIEM) celebrated its 50th anniversary on July 1, 2011. This article reviews its history, evolution, and transition of its research programs as well as its scientific and military accomplishments, emphasizing the past 25 yr. During the 1990s, USARIEM published a series of pocket guides providing guidance for sustaining Warfighter health and performance in Southwest Asia, Somalia, the former Republic of Yugoslavia, Rwanda, and Haiti. Issues identified during Operation Desert Storm elicited research that improved nutritional guidelines for protracted desert operations; safer use of nuclear, chemical, and biological protective clothing; equipment, development, and fielding of efficient microclimate cooling systems; and effective evaluation of pharmaceuticals to protect soldiers from chemical and biological threats. During the first decade of the 21st century, USARIEM and the Department of the Army published official medical/performance doctrines for operations in the heat and cold and at high altitude. The current Global War on Terrorism focused research to improve doctrines for hot, cold, and high-altitude operations, reduce musculoskeletal training injuries, provide improved field nutrition, more efficient planning for operational water requirements, and improve both military clothing and materiel. This article also describes the critically important interactions and communications between USARIEM and deployed units and the benefits to Warfighters from this association. This report presents USARIEM's unique and world-class facilities, organizational changes, scientific and support personnel, and major research accomplishments, including the publication of 2,200 scientific papers over the past 25 yr.
ResearchGate has not been able to resolve any references for this publication.