scholarly journals Heat stress in hot US mines and criteria for Standards for mining in hot environments

1978 ◽  
Vol 9 (2) ◽  
pp. 109-110
Keyword(s):  
2013 ◽  
pp. 47-57
Author(s):  
Van Trong Le ◽  
Thi Tuyet Mai Nguyen ◽  
Thi Xuan Duyen Nguyen ◽  
Ba Luan Nguyen ◽  
Tuyen Pham ◽  
...  

Objectives: Presents heat stress Standard ISO 7243, which is based upon the wet bulb globe temperature index (WBGT), and considers its suitability for use worldwide. Materials and Methods: The WBGT index are considered and how it is used in ISO 7243 and across the world as a simple index for monitoring and assessing hot environments. Results: Management systems, involving risk assessments, that take account of context and culture, are required to ensure successful use of the standard and global applicability. For use outdoors, a WBGT equation that includes solar absorptivity is recommended. A ‘clothed WBGT’ is proposed to account for the effects of clothing. Conclusion: ISO 7243 is a simple tool to assess the heat stress and may be applicated worldwide.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Samira Mafi Moghaddam ◽  
Atena Oladzad ◽  
Chushin Koh ◽  
Larissa Ramsay ◽  
John P. Hart ◽  
...  

AbstractTepary bean (Phaseolus acutifolis A. Gray), native to the Sonoran Desert, is highly adapted to heat and drought. It is a sister species of common bean (Phaseolus vulgaris L.), the most important legume protein source for direct human consumption, and whose production is threatened by climate change. Here, we report on the tepary genome including exploration of possible mechanisms for resilience to moderate heat stress and a reduced disease resistance gene repertoire, consistent with adaptation to arid and hot environments. Extensive collinearity and shared gene content among these Phaseolus species will facilitate engineering climate adaptation in common bean, a key food security crop, and accelerate tepary bean improvement.


Author(s):  
Ed Maunder ◽  
Daniel J. Plews ◽  
Fabrice Merien ◽  
Andrew E. Kilding

Many endurance athletes perform specific blocks of training in hot environments in “heat stress training camps.” It is not known if physiological threshold heart rates measured in temperate conditions are reflective of those under moderate environmental heat stress. A total of 16 endurance-trained cyclists and triathletes performed incremental exercise assessments in 18°C and 35°C (both 60% relative humidity) to determine heart rates at absolute blood lactate and ventilatory thresholds. Heart rate at fixed blood lactate concentrations of 2, 3, and 4 mmol·L−1 and ventilatory thresholds were not significantly different between environments (P > .05), despite significant heat stress-induced reductions in power output of approximately 10% to 17% (P < .05, effect size = 0.65–1.15). The coefficient of variation for heart rate at these blood lactate concentrations (1.4%−2.9%) and ventilatory thresholds (2.3%−2.7%) between conditions was low, with significant strong positive correlations between measurements in the 2 environments (r = .92–.95, P < .05). These data indicate heart rates measured at physiological thresholds in temperate environments are reflective of measurements taken under moderate environmental heat stress. Therefore, endurance athletes embarking on heat stress training camps can use heart rate–based thresholds ascertained in temperate environments to prescribe training under moderate environmental heat stress.


2015 ◽  
Vol 16 (1) ◽  
pp. 21-25
Author(s):  
Jelena Maric ◽  
Milan Marjanovic ◽  
Dalibor Jovanovic ◽  
Filip Stojanovic ◽  
Djordje Vukmirovic ◽  
...  

ABSTRACTHeat stress is a significant problem in the military services. This study investigated the effects of exertional heat stress on cognitive performance.Forty unacclimated male soldiers performed exertional heat stress tests in cool (20 °C) and hot environments (40 °C). Cognitive performance was assessed using a computerized battery before and immediately after tests. Physical strain in cool conditions induced mild but significant deficits in accuracy in complex tests. The number of correct answers in the Matching to Sample Visual Search was reduced (92,18% correct answers before vs. 88,64 after; p<0,05) and also in the spatial part of the Pattern and Spatial Recognition Memory Test (85,25 vs. 8,75%; p<0,05). These decreases were more pronounced in hot conditions (92,38 vs. 84,31% in before and 84,21 vs. 73,42% in the latter test; ps<0,01 and <0,001, respectively). Exertional heat stress also impaired more simple cognitive functions. A significant decrease in accuracy (95,74 vs. 93,89%) and an increase in reaction time (300,32 vs. 315,00 ms) was observed in the Reaction Time test.Strenuous physical activity in a hot environment induces mild cognitive deficits, especially in more complex tasks.


2021 ◽  
Vol 24 (1) ◽  
pp. 13-23
Author(s):  
S Sharmin ◽  
MA Hasan ◽  
S Sikder

Four wheat variety/genotype (BARI Gom-26, BAW-1202, BAW-1182 and BARI Gom-27) were tested under three heat stress regimes (normal, moderate and severe) to evaluate the effect of late seeding warmer condition on phenology and yield of wheat, as well as to identify suitable cultivars to develop heat-tolerant genotypes at Hajee Mohammad Danesh Science and Technology University (HSTU), Dinajpur during November, 2016 to April, 2017. Results revealed that genotype BAW-1182 and BAW-1202 showed greater thermostability of cell membrane with acceptable yield performance under heat stress condition. The order of tolerance based on heat susceptibility index (based on grain yield) was BAW-1182>BAW-1202>BARI Gom-27>BARI Gom-26 under heat stress conditions. Thus, BAW-1182 and BAW-1202 have the greatest potential to be used as high-yielding wheat genotypes under warm to hot environments and could be used in a breeding programme to develop heat-tolerant wheat. Bangladesh Agron. J. 2021, 24(1): 13-23


Author(s):  
Rajabali Hokmabadi ◽  
Vida Rezaei-Hachesu ◽  
Meghdad Kazemi ◽  
Hossein Fallah ◽  
Farideh Golbabaei

Background: activity in hot environments is among the most common physical dangers in work environments that not only creates diseases resultant from heat which influences on staff’s health but also increases job injuries and accidents. Job injuries, diseases, and reduction in workers' efficiency in exposure to heat stress have caused increasing anxiety. Most of the study results are demonstrative of diseases as a result of heat and less related to job injuries and accidents. Therefore, the present study aims at reviewing previous studies in the field of job injuries and accidents in exposure to the work environment's heat stress. Methods: this review study has systematically reviewed publications and articles from 2000 to 2019 in databases. Keywords including "heat stress”, “heat strain”, “heat exposure”, “heat wave", "heat injuries”, “job accidents”, “job exposure”, “hot environment” and “air change" have been used and finally, 30 articles included into the study. Results: study articles consist of 29 jobs and 1 military environment. Study occupations consist of one study about military forces, textile, aluminum smelting, cleaners of oil reservoirs, two studies about mineworkers and metal and iron industries, three studies about building workers, four studies about agricultural workers and 15 studies about different occupations. Also, 11 studies conducted in open environments, seven studies in closed environments and 12 others conducted both in open and closed environments. 17 analytical studies, three correlational, cross-sectional, cohort studies, one cohort, and descriptive study and two descriptive-analytical studies have been conducted. Most job injuries and accidents happened during summer and men especially the young have involved in such problems and job injuries and accidents have increased due to extreme temperature increase. Generally, job injuries and accidents include burn, slip, collision with things and collision with mobile things. Conclusion: there is a strong relationship between temperature in hot environments and risk increase in injuries and accidents of work environments which differ based on employees' features (such as age, gender, occupation, and industry). However, dominant mechanisms on the happening of such injuries have not been determined yet. It necessitates more expertise to determine especial injuries and accidents happening in hot environments. Policymakers and employers have to be more aware of job injuries and accidents in heat exposure and suitable educational resources have to be provided to prevent such injuries.


1965 ◽  
Vol 20 (2) ◽  
pp. 288-292 ◽  
Author(s):  
C. R. Bell ◽  
R. F. Hellon ◽  
R. W. Hiorns ◽  
P. B. Nicol ◽  
K. A. Provins

Eight men were exposed to hot environments which ranged from 37 C/30 C to 63 C/47 C dry- and wet-bulb temperatures. They remained in the heat until they showed signs of distress just before collapsing. The time taken to reach this state was found to be hyperbolically related to the severity of the environment when this was expressed as a weighted sum of wet- and dry-bulb temperatures. Separate hyperbolae were found for standing and working subjects. After the deduction of a suitable safety margin, the resulting curves and their equations make possible the prediction of safe exposure times for severe heat heat stress; heat collapse; heat tolerance Submitted on May 13, 1964


Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 867 ◽  
Author(s):  
Aleena Joy ◽  
Frank R. Dunshea ◽  
Brian J. Leury ◽  
Iain J. Clarke ◽  
Kristy DiGiacomo ◽  
...  

Climate change is a major global threat to the sustainability of livestock systems. Climatic factors such as ambient temperature, relative humidity, direct and indirect solar radiation and wind speed influence feed and water availability, fodder quality and disease occurrence, with production being most efficient in optimal environmental conditions. Among these climatic variables, ambient temperature fluctuations have the most impact on livestock production and animal welfare. Continuous exposure of the animals to heat stress compromises growth, milk and meat production and reproduction. The capacity of an animal to mitigate effects of increased environmental temperature, without progressing into stress response, differs within and between species. Comparatively, small ruminants are better adapted to hot environments than large ruminants and have better ability to survive, produce and reproduce in harsh climatic regions. Nevertheless, the physiological and behavioral changes in response to hot environments affect small ruminant production. It has been found that tropical breeds are more adaptive to hot climates than high-producing temperate breeds. The growing body of knowledge on the negative impact of heat stress on small ruminant production and welfare will assist in the development of suitable strategies to mitigate heat stress. Selection of thermotolerant breeds, through identification of genetic traits for adaption to extreme environmental conditions (high temperature, feed scarcity, water scarcity), is a viable strategy to combat climate change and minimize the impact on small ruminant production and welfare. This review highlights such adaption within and among different breeds of small ruminants challenged by heat stress.


2020 ◽  
pp. jramc-2019-001253 ◽  
Author(s):  
Jo Corbett ◽  
J Wright ◽  
M J Tipton

Women can now serve in ground close combat (GCC) roles, where they may be required to operate alongside men in hot environments. However, relative to the average male soldier, female soldiers are less aerobically fit, with a smaller surface area (AD), lower mass (m) with higher body fat and a larger AD/m ratio. This increases cardiovascular strain, reduces heat exchange with the environment and causes a greater body temperature increase for a given heat storage, although a large AD/m ratio can be advantageous. Physical employment standards for GCC roles might lessen the magnitude of fitness and anthropometric differences, yet even when studies control for these factors, women sweat less than men at high work rates. Therefore, the average female soldier in a GCC role is likely to be at a degree of disadvantage in many hot environments and particularly during intense physical activity in hot-arid conditions, although heat acclimation may mitigate some of this effect. Any thermoregulatory disadvantage may be exacerbated during the mid-luteal phase of the menstrual cycle, although the data are equivocal. Likewise, sex differences in behavioural thermoregulation and cognition in the heat are not well understood. Interestingly, there is often lower reported heat illness incidence in women, although the extent to which this is influenced by behavioural factors or historic differences in role allocation is unclear. Indeed, much of the extant literature lacks ecological validity and more work is required to fully understand sex differences to exercise heat stress in a GCC context.


2010 ◽  
Vol 109 (6) ◽  
pp. 1989-1995 ◽  
Author(s):  
Samuel N. Cheuvront ◽  
Robert W. Kenefick ◽  
Scott J. Montain ◽  
Michael N. Sawka

Environmental heat stress can challenge the limits of human cardiovascular and temperature regulation, body fluid balance, and thus aerobic performance. This minireview proposes that the cardiovascular adjustments accompanying high skin temperatures (Tsk), alone or in combination with high core body temperatures (Tc), provide a primary explanation for impaired aerobic exercise performance in warm-hot environments. The independent (Tsk) and combined (Tsk + Tc) effects of hyperthermia reduce maximal oxygen uptake (V̇o2max), which leads to higher relative exercise intensity and an exponential decline in aerobic performance at any given exercise workload. Greater relative exercise intensity increases cardiovascular strain, which is a prominent mediator of rated perceived exertion. As a consequence, incremental or constant-rate exercise is more difficult to sustain (earlier fatigue) or requires a slowing of self-paced exercise to achieve a similar sensation of effort. It is proposed that high Tsk and Tc impair aerobic performance in tandem primarily through elevated cardiovascular strain, rather than a deterioration in central nervous system (CNS) function or skeletal muscle metabolism. Evaporative sweating is the principal means of heat loss in warm-hot environments where sweat losses frequently exceed fluid intakes. When dehydration exceeds 3% of total body water (2% of body mass) then aerobic performance is consistently impaired independent and additive to heat stress. Dehydration augments hyperthermia and plasma volume reductions, which combine to accentuate cardiovascular strain and reduce V̇o2max. Importantly, the negative performance consequences of dehydration worsen as Tsk increases.


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