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1.
Hot weather and heat extremes: health risks.
Ebi, KL, Capon, A, Berry, P, Broderick, C, de Dear, R, Havenith, G, Honda, Y, Kovats, RS, Ma, W, Malik, A, et al
Lancet (London, England). 2021;(10301):698-708
Abstract
Hot ambient conditions and associated heat stress can increase mortality and morbidity, as well as increase adverse pregnancy outcomes and negatively affect mental health. High heat stress can also reduce physical work capacity and motor-cognitive performances, with consequences for productivity, and increase the risk of occupational health problems. Almost half of the global population and more than 1 billion workers are exposed to high heat episodes and about a third of all exposed workers have negative health effects. However, excess deaths and many heat-related health risks are preventable, with appropriate heat action plans involving behavioural strategies and biophysical solutions. Extreme heat events are becoming permanent features of summer seasons worldwide, causing many excess deaths. Heat-related morbidity and mortality are projected to increase further as climate change progresses, with greater risk associated with higher degrees of global warming. Particularly in tropical regions, increased warming might mean that physiological limits related to heat tolerance (survival) will be reached regularly and more often in coming decades. Climate change is interacting with other trends, such as population growth and ageing, urbanisation, and socioeconomic development, that can either exacerbate or ameliorate heat-related hazards. Urban temperatures are further enhanced by anthropogenic heat from vehicular transport and heat waste from buildings. Although there is some evidence of adaptation to increasing temperatures in high-income countries, projections of a hotter future suggest that without investment in research and risk management actions, heat-related morbidity and mortality are likely to increase.
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2.
Occupational heat exposure and the risk of chronic kidney disease of nontraditional origin in the United States.
Chapman, CL, Hess, HW, Lucas, RAI, Glaser, J, Saran, R, Bragg-Gresham, J, Wegman, DH, Hansson, E, Minson, CT, Schlader, ZJ
American journal of physiology. Regulatory, integrative and comparative physiology. 2021;(2):R141-R151
Abstract
Occupational heat exposure is linked to the development of kidney injury and disease in individuals who frequently perform physically demanding work in the heat. For instance, in Central America, an epidemic of chronic kidney disease of nontraditional origin (CKDnt) is occurring among manual laborers, whereas potentially related epidemics have emerged in India and Sri Lanka. There is growing concern that workers in the United States suffer with CKDnt, but reports are limited. One of the leading hypotheses is that repetitive kidney injury caused by physical work in the heat can progress to CKDnt. Whether heat stress is the primary causal agent or accelerates existing underlying pathology remains contested. However, the current evidence supports that heat stress induces tubular kidney injury, which is worsened by higher core temperatures, dehydration, longer work durations, muscle damaging exercise, and consumption of beverages containing high levels of fructose. The purpose of this narrative review is to identify occupations that may place US workers at greater risk of kidney injury and CKDnt. Specifically, we reviewed the scientific literature to characterize the demographics, environmental conditions, physiological strain (i.e., core temperature increase, dehydration, heart rate), and work durations in sectors typically experiencing occupational heat exposure, including farming, wildland firefighting, landscaping, and utilities. Overall, the surprisingly limited available evidence characterizing occupational heat exposure in US workers supports the need for future investigations to understand this risk of CKDnt.
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3.
High temperature susceptibility of sexual reproduction in crop plants.
Lohani, N, Singh, MB, Bhalla, PL
Journal of experimental botany. 2020;(2):555-568
Abstract
Climate change-induced increases in the frequency of extreme weather events, particularly heatwaves, are a serious threat to crop productivity. The productivity of grain crops is dependent on the success of sexual reproduction, which is very sensitive to heat stress. Male gametophyte development has been identified as the most heat-vulnerable stage. This review outlines the susceptibility of the various stages of sexual reproduction in flowering plants from the time of floral transition to double fertilization. We summarize current knowledge concerning the molecular mechanisms underpinning the heat stress-induced aberrations and abnormalities at flowering, male reproductive development, female reproductive development, and fertilization. We highlight the stage-specific bottlenecks in sexual reproduction, which regulate seed set and final yields under high-temperature conditions, together with the outstanding research questions concerning genotypic and species-specific differences in thermotolerance observed in crops. This knowledge is essential for trait selection and genetic modification strategies for the development of heat-tolerant genotypes and high-temperature-resilient crops.
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4.
Overview of Existing Heat-Health Warning Systems in Europe.
Casanueva, A, Burgstall, A, Kotlarski, S, Messeri, A, Morabito, M, Flouris, AD, Nybo, L, Spirig, C, Schwierz, C
International journal of environmental research and public health. 2019;(15)
Abstract
The frequency of extreme heat events, such as the summer of 2003 in Europe, and their corresponding consequences for human beings are expected to increase under a warmer climate. The joint collaboration of institutional agencies and multidisciplinary approaches is essential for a successful development of heat-health warning systems and action plans which can reduce the impacts of extreme heat on the population. The present work constitutes a state-of-the-art review of 16 European heat-health warning systems and heat-health action plans, based on the existing literature, web search (over the National Meteorological Services websites) and questionnaires. The aim of this study is to pave the way for future heat-health warning systems, such as the one currently under development in the framework of the Horizon 2020 HEAT-SHIELD project. Some aspects are highlighted among the variety of examined European warning systems. The meteorological variables that trigger the warnings should present a clear link with the impact under consideration and should be chosen depending on the purpose and target of the warnings. Setting long-term planning actions as well as pre-alert levels might prevent and reduce damages due to heat. Finally, education and communication are key elements of the success of a warning system.
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5.
Erythema ab igne: new technology rebounding upon its users?
Salgado, F, Handler, MZ, Schwartz, RA
International journal of dermatology. 2018;(4):393-396
Abstract
Erythema ab igne (EAI) is a persistent, chronic skin condition resulting from prolonged exposure to infrared radiation, experienced as heat. Once associated with traditional warming sources like wood burning stoves or open fires, modern, infrared exposure originates also from newer sources like laptops and heating pads and may be creating a rebound of EAI. The epidemiology may be different too, with younger patients than previously seen. Localized EAI over an area of pain in the abdomen or lower back can be a sign of an underlying disorder, including cancer. Prognosis of EAI is good, with removal of the heat source resulting in complete remission. In chronic cases in which premalignant cutaneous dysplasia has resulted, additional treatments may be necessary including topical retinoids, 5-fluorouracil cream, and laser treatments. Rarely, cancers such as squamous cell carcinoma, Merkel cell carcinoma, and cutaneous marginal zone B cell lymphoma have been associated with longstanding EAI.
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6.
Cooling During Exercise: An Overlooked Strategy for Enhancing Endurance Performance in the Heat.
Stevens, CJ, Taylor, L, Dascombe, BJ
Sports medicine (Auckland, N.Z.). 2017;(5):829-841
Abstract
It is well established that endurance performance is negatively affected by environmental heat stress due to a complex interaction of physical, physiological and psychological alterations. Numerous scientific investigations have attempted to improve performance in the heat with pre-cooling (cooling prior to an exercise test), and as such this has become a well-established ergogenic practice for endurance athletes. However, the use of mid-cooling (cooling during an exercise test) has received considerably less research attention in comparison, despite recent evidence to suggest that the advantage gained from mid-cooling may outweigh that of pre-cooling. A range of mid-cooling strategies are beneficial for endurance performance in the heat, including the ingestion of cold fluids and ice slurry, both with and without menthol, as well as cooling of the neck and face region via a cooling collar or water poured on the head and face. The combination of pre-cooling and mid-cooling has also been effective, but few comparisons exist between the timing and type of such interventions. Therefore, athletes should experiment with a range of suitable mid-cooling strategies for their event during mock competition scenarios, with the aim to determine their individual tolerable limits and performance benefits. Based on current evidence, the effect of mid-cooling on core temperature appears largely irrelevant to any subsequent performance improvements, while cardiovascular, skin temperature, central nervous system function and psychophysiological factors are likely involved. Research is lacking on elite athletes, and as such it is currently unclear how this population may benefit from mid-cooling.
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7.
High temperatures and nephrology: The climate change problem.
de Lorenzo, A, Liaño, F
Nefrologia : publicacion oficial de la Sociedad Espanola Nefrologia. 2017;(5):492-500
Abstract
It is well known that climate change greatly affects human health, even though there are few studies on renal outcomes. Heat waves have been found to increase cardiovascular and respiratory morbidity and mortality, as well as the risk of acute renal failure and hospitalisation due to renal diseases, with related mortality. Recurrent dehydration in people regularly exposed to high temperatures seems to be resulting in an unrecognised cause of proteinuric chronic kidney disease, the underlying pathophysiological mechanism of which is becoming better understood. However, beyond heat waves and extreme temperatures, there is a seasonal variation in glomerular filtration rate that may contribute to the onset of renal failure and electrolyte disorders during extremely hot periods. Although there are few references in the literature, serum sodium disorders seem to increase. The most vulnerable population to heat-related disease are the elderly, children, chronic patients, bedridden people, disabled people, people living alone or with little social contact, and socioeconomically disadvantaged people.
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8.
Farmworker Vulnerability to Heat Hazards: A Conceptual Framework.
Mac, VVT, McCauley, LA
Journal of nursing scholarship : an official publication of Sigma Theta Tau International Honor Society of Nursing. 2017;(6):617-624
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Abstract
PURPOSE To review factors that impact the effect of hot environments on the human body in order to develop a conceptual model of human biological response. METHODS The organizing concept for the model development was the multilevel integration of three major factors, exposure to heat, sensitivity and adaptive capacity, and the heat stress response. Exposure of a vulnerable occupational group was used to illustrate the components of the model. FINDINGS Components of this framework include the hazard (environmental heat stress), vulnerability factors (workplace exposure, sensitivity and adaptive capacity), and the heat stress response. The combination of the vulnerability factors of workplace exposure (work intensity, duration), sensitivity (age, gender, etc.), and adaptive capacity (hydration, clothing, work hygiene) mediate a worker's heat stress response to the hazard. A worker's heat stress response can be classified as progressing towards two outcomes: physiologic equilibrium or physiologic disequilibrium. CONCLUSIONS This framework provides a starting point for the design and development of studies of heat-related illness (HRI) in farmworker and other vulnerable populations exposed to rising global temperatures. CLINICAL RELEVANCE Identification of vulnerability factors to HRI, informs research designs which will lead to the development of public health interventions.
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9.
A Critical Review of OSHA Heat Enforcement Cases: Lessons Learned.
Arbury, S, Lindsley, M, Hodgson, M
Journal of occupational and environmental medicine. 2016;(4):359-63
Abstract
OBJECTIVES The aim of the study was to review the Occupational Safety and Health Administration's (OSHA) 2012 to 2013 heat enforcement cases, using identified essential elements of heat illness prevention to evaluate employers' programs and make recommendations to better protect workers from heat illness. METHODS (1) Identify essential elements of heat illness prevention; (2) develop data collection tool; and (3) analyze OSHA 2012 to 2013 heat enforcement cases. RESULTS OSHA's database contains 84 heat enforcement cases in 2012 to 2013. Employer heat illness prevention programs were lacking in essential elements such as providing water and shade; adjusting the work/rest proportion to allow for workload and effective temperature; and acclimatizing and training workers. CONCLUSIONS In this set of investigations, most employers failed to implement common elements of illness prevention programs. Over 80% clearly did not rely on national standard approaches to heat illness prevention.
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10.
Sprint performance under heat stress: A review.
Girard, O, Brocherie, F, Bishop, DJ
Scandinavian journal of medicine & science in sports. 2015;:79-89
Abstract
Training and competition in major track-and-field events, and for many team or racquet sports, often require the completion of maximal sprints in hot (>30 °C) ambient conditions. Enhanced short-term (<30 s) power output or single-sprint performance, resulting from transient heat exposure (muscle temperature rise), can be attributed to improved muscle contractility. Under heat stress, elevations in skin/core temperatures are associated with increased cardiovascular and metabolic loads in addition to decreasing voluntary muscle activation; there is also compelling evidence to suggest that large performance decrements occur when repeated-sprint exercise (consisting of brief recovery periods between sprints, usually <60 s) is performed in hot compared with cool conditions. Conversely, poorer intermittent-sprint performance (recovery periods long enough to allow near complete recovery, usually 60-300 s) in hotter conditions is solely observed when exercise induces marked hyperthermia (core temperature >39 °C). Here we also discuss strategies (heat acclimatization, precooling, hydration strategies) employed by "sprint" athletes to mitigate the negative influence of higher environmental temperatures.