Evaluation Of Heat Stress Research Articles

Corticosterone tissue-specific response in Sprague Dawley rats under acute heat stress

Our study evaluated the physiological responses to acute heat stress in rats via body temperature and tissue corticosterone levels, and investigated the relative tissue response to heat stress based on corticosterone. Body temperature of rats under 22 °C (control) and 42 °C for 30 (H30), 60 (H60) and 120 min (H120) was measured. Correspondingly, corticosterone was analyzed in 11 tissues (adrenal, brain, heart, kidney, liver, lung, leg muscle, blood, stomach, spleen and small intestine). Analysis of variance and correlations were conducted on body temperature and corticosterone levels. The receiver operating characteristic (ROC) analyzed the thermo-sensitivity via corticosterone. Body temperature of rats in H30, H60 and H120 groups were higher (P < 0.05) than the control. Compared to the control, corticosterone levels of heart, stomach and small intestine at H30, corticosterone levels in adrenal, leg muscle and stomach at H60, and corticosterone levels in adrenal, heart, lung, stomach and small intestine at H120 differed (P < 0.05). The corticosterone in lung tissue was an excellent indicator of acute heat stress, with an area under the curve (AUC) of 1.00 at H60 and H120. In order to improve the prediction of acute heat stress, models combining corticosterone levels of multiple tissues reached an AUC of 1.00 for H30, and the sensitivity increased to 100% for H60 and H120. In conclusion, changes in the patterns and thermosensitivity of corticosterone levels associated with the duration of heat stress across body tissues were evidenced. The single and multi-organizational corticosterone models serve as indicators for evaluating heat stress across different time periods.

Infrared thermography as a non-invasive method for the evaluation of heat stress in pigs kept in pens free of cages in the maternity

Infrared thermography is a non-invasive method of body surface temperature analysis in pigs. This study aimed to evaluate the body surface temperature of sows and piglets kept in individual pens free of cages with or without cooling system with the use of infrared thermography. The study was conducted during the summer and autumn in Pirassununga, Brazil. Twenty-six sows during lactating phase and 281 piglets until 21 days-old were evaluated in two treatments: cooled pens with fans and water sprinklers on the roof and non-cooled pens. Both areas had ceramic roof tiles. Thermographic images were collected at intervals of seven days in the morning and afternoon in sows and randomly in five piglets per litter, and salivary cortisol were collected only on sows. The thermographic images were analyzed using the software IRSoft Version 3.6 Testo. Every three days respiratory rate and rectal temperatures were collected from sows and five piglets per litter. It was included fixed effect of treatment, period of the day, seasons and their interactions, besides the correlations of Pearson. In summer and autumn, the hottest surface area of sows was the mammary gland and the coldest the vaginal. For the piglets, the hottest area in the summer was the head and the coldest the snout. Summer presented the highest surface temperatures of the sugarcane bagasse bed, concrete floor and roof. No correlations were found between air temperature of and facilities. The respiratory rate presented moderate correlation with the back and with the snout of the sows. Rectal temperatures were higher in summer and in the afternoon, but it was similar between treatments. Although the cooling system had reduced the air temperature of the pens free of cage, it was not enough to reduce body superficial temperatures of the sows and piglets during lactating phase. Nevertheless, the use of infrared thermography allows to identify the hottest and coldest surface body areas of pigs and can be a tool to assess pig facilities and animal welfare.

Effects of heat stress on body temperature, milk production, and reproduction in dairy cows: a novel idea for monitoring and evaluation of heat stress — A review

Heat stress exerts a substantial effect on dairy production. The temperature and humidity index (THI) is widely used to assess heat stress in dairy operations. Herein, we review the effects of high temperature and humidity on body temperature, feed intake, milk production, follicle development, estrous behavior, and pregnancy in dairy cows. Analyses of the effects of THI on dairy production have shown that body temperature is an important physiological parameter in the evaluation of the health state of dairy cows. Although THI is an important environmental index and can help to infer the degree of heat stress, it does not reflect the physiological changes experienced by dairy cows undergoing heat stress. However, the simultaneous measurement of THI and physiological indexes (e.g., body temperature) would be very useful for improving dairy production. The successful development of automatic detection techniques makes it possible to combine THI with other physiological indexes (i.e., body temperature and activity), which could help us to comprehensively evaluate heat stress in dairy cows and provide important technical support to effectively prevent heat stress.

Evaluation of Environmental Heat Stress on Physical and Hormonal Parameters in Murrah Buffalo

Evaluation of Environmental Heat Stress on Physical and Hormonal Parameters in Murrah Buffalo

Exploration of factors determining milk production by Holstein cows raised on a dairy farm in a temperate climate area.

In this study, we examined factors that affected milk production by cows raised in a temperate climate area. We conducted this study on a large dairy farm containing approximately 2000 Holstein cows, located in a temperate climate area. We collected 7803 calving records for 4069 cows from 2012 to 2016. We then assessed the effect of hot weather on milk yield by examining three climate factors: season, maximum temperature (MAX), and the temperature and humidity index (THI). We found that increases in heat stress caused linear decreases in milk yield (P < 0.05). Additionally, the effects of the three climate factors on milk yield varied depending on cow parity and days open (P < 0.05). Thus, management procedures should consider cow parity and lactating stage to minimize the negative effects of heat stress on milk production. We also found that the lowest Akaike information criterion value was obtained in our model when using THI for 305-day milk yield. This suggests that THI is a more accurate variable for evaluating heat stress than MAX or season.

Evaluation of indoor heat stress on workers of bakeries at Assiut City, Egypt

This study investigates indoor heat stress among employees engaged in bakeries in Assiut city. Heat stress is one of the occupational hazards especially in arid climates that impose negative impacts on workers such as heat rashes, heat exhaustion, heat cramps, heat fainting or heat stroke. In this research, 100 subjects were chosen randomly from 20 bakery stations to testify heat stress impacts. Heat stress levels were measured using wet-bulb globe temperature index (WBGT) to evaluate the impacts of environmental factors on the employees. The response of worker’s body to this heat stress is expressed as physiological strain index (PSI) that can be estimated by measuring heart rate and core temperature. Results obtained from WBGT index measurements indicated that the average value of heat stress in bakeries reached 31.6 °C that is exceeding than threshold limit value (28 °C) and action limit (25 °C) recommended by American Conference of Government Industrial Hygienists. In addition, WBGT values were compared with the Egyptian Environmental Law 4/1994 and Egyptian Labor Low 12/2003. PSI values fall in the range of 200 < M (metabolic rate) < 260 indicating that workload in bakeries environment lies in the moderate class. According to the questionnaire data, several workers faced heat disorders including heat exhaustion (23 cases), heat cramps (17 cases), and heat stroke (5 cases). Application of control measures such as engineering control, administrative control, and personal protective equipment should be applied.

The potential of local climate zones maps as a heat stress assessment tool, supported by simulated air temperature data

High population densities in cities and rapid urban growth increase the vulnerability of the urban environment to extreme weather events. Urban planning should account for these extreme events as efficiently as possible. One way is to locate hot spots in an urban environment by mapping cities into local climate zones (LCZ) and evaluate heat stress related to these zones. LCZs are likely to become a standard in urban climate modelling as they capture important urban morphological characteristics. For instance, temperature regimes linked to spatially explicit LCZ maps should be assessed for all LCZ zones derived from these maps. This study assesses the thermal behavior of mapped LCZs using simulated temperature data from the UrbClim model. Prior to temperature analysis, the model was validated with observational data. To evaluate the robustness of the analysis, we ran the model in three cities in Belgium: Antwerp, Brussels, and Ghent. The results show that temperature regimes are significantly different for all the built zones in the urban environment independent of the city. Second, the susceptibility to heat stress can differ greatly depending on the zone. The unique thermal behavior of the different LCZs provides indispensable information on the urban environment and its climatic conditions. This study shows that the LCZ scheme has a potential to help urban planners globally tackle adverse effects of extreme weather events.

Attenuating heat stress through green roof and green wall retrofit

The process of rapid urbanisation is becoming problematic due to the reduction in, and lack of compensation of, previously vegetated areas. With a combination of green roofs and green walls, adopted on a large scale, it is possible to attenuate the urban heat island effect and internal temperatures in buildings. Tall buildings are becoming a common housing type in many cities, and considering the role of external walls in heat gain, it is expected that the combination of green roofs and green walls have great potential to improve thermal performance. As only 1-2% is added to the total stock of buildings annually, the focus should be on the retrofit of existing buildings to deliver maximum thermal benefits. In the present work lightweight, modular vegetated systems were adopted for roofs and walls. Instead of considering only the temperature influence in heat stress, this research adopted the use of heat index that encompasses the combined effect of temperature and relative humidity. For this purpose, the thermal benefits of green roof and green wall retrofit is evaluated in two small scale experiments, where identical prototypes (vegetated and non-vegetated) are compared using block work and timber framed drywall structures for Rio de Janeiro, Brazil and Sydney, Australia, respectively. The results show a different understanding in heat stress evaluation regarding heat index rather than temperature itself, especially under high levels of relative humidity. This evidence demonstrates green roof and green wall retrofit offer a proven role in heat stress attenuation in residential buildings.

Characterizing Heat Stress and Strain in Electric Utility Workers by Means of a Questionnaire

In recent field work we showed that the high physical demands combined with restrictions to heat loss due to protective work uniforms caused some electric utility workers to experience dangerous levels of hyperthermia (J Occup Environ Hyg. 2015;12:708). These findings indicate that heat stress in the electric utility industry may be detrimental to worker health and safety. In the present study, 414 workers in the power generation and delivery industry across 15 US states completed a two‐part on‐line questionnaire anonymously. Part 1 comprised 15 general questions on the worker's age, sex, role in the organization, general duties, workplace location, work shift duration, years of experience, level of physical activity, frequency of heat exposure, other. The second part consisted of a validated questionnaire for the assessment of heat stress at the workplace – the ‘Heat Strain Score Index (HSSI)’ (Int J Prev Med 2013; 4:631). It was composed of 18 questions which included key factors in heat stress evaluation (environmental parameters, work intensity, level of heat exposure, clothing insulation and permeability, etc.) and indicators of heat strain (sweat rate, fatigue, thirst, symptoms of heat‐related illness, etc.) with cut‐off scores as follows: ≤13.5, green zone or safe level; 13.6 to 18.0, yellow zone or alarm level; &gt;18.0, red zone or danger level. The average (±SD) age of the respondents was 46(10) years and they reported being in their present position for 11(10) years. They typically performed 5(1) consecutive days of work lasting 10(6) hours each day. For all job types (all workers), 79% of respondents reported heat stress was a problem. This number was greater (93%) in those performing physically demanding jobs (e.g. linesman). Further, 30% and 67% of all workers indicated they were exposed to heat stress occasionally and daily, respectively. In contrast, 81% of linesman reported being exposed to heat stress on a daily basis with only 19% experiencing occasional exposure. Based on the HSSI, 43% of all workers and 68% of linesman were categorized in the red zone (danger level) and therefore at an elevated risk of a heat‐related injury (both p&lt;0.01). Our findings demonstrate that electric utility workers are likely to experience excessive heat strain and research must be conducted to explore methods to effectively and efficiently manage heat stress and strain in these workers.Support or Funding InformationHuman and Environmental Physiology Research Unit (G.P. Kenny).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Performance and Stability of Commercial Wheat Cultivars under Terminal Heat Stress

Egypt, the fifteenth most populated country and the largest wheat importer worldwide, is vulnerable to global warming. Ten of the commercial and widely grown wheat cultivars were planted in two locations, i.e., Elbostan and Elkhazan for three successive seasons 2014/2015, 2015/2016, and 2016/2017 under two sowing dates (recommended and late). Elbostan and Elkhazan are the two locations used in this study because they represent newly reclaimed sandy soil and the Nile delta soil (clay), respectively. A split-plot, with main plots arranged as a randomized complete block design and three replicates, was used. The overall objective of this study was to identify the ideal cultivar for recommended conditions and heat stressed conditions. The results revealed that heat stress had a significant adverse impact on all traits while it raised the prevalence and severity of leaf and stem rust which contributed to overall yield losses of about 40%. Stability measurements, the additive main effects and multiplicative interaction model (AMMI) and genotype main effect plus genotype × environment interaction (GGE), were useful to determine the ideal genotypes for recommended and late sowing conditions (heat stressed). However, inconsistency was observed among some of these measurements. Cultivar “Sids12” was stable and outperformed other tested cultivars under combined sowing dates across environments. However, cultivar “Gemmeiza9” was more stable and outperformed other cultivars across environments under the recommended sowing date. Moreover, cultivar “Gemmeiza12” was the ideal cultivar for the late sown condition. Based on our findings, importing and evaluating heat stress tolerant wheat genotypes under late sown conditions or heat stressed conditions in Egypt is required to boost heat stress tolerance in the adapted wheat cultivars.

Quality evaluation of heat stress treated Radix saposhnikoviae using pharmacokinetic and pharmacologic methods

Quality evaluation of heat stress treated Radix saposhnikoviae using pharmacokinetic and pharmacologic methods

Evaluation of heat stress at site of open-air music festival and survey on preventive behaviors of visitors for heat stress in summer and autumn

Evaluation of heat stress at site of open-air music festival and survey on preventive behaviors of visitors for heat stress in summer and autumn

Evaluation of Heat Stress in Construction Site of Metro Rail in Chennai.

Introduction:Tunnel boring machine (TBM) is used for constructing a tunnel. Worn out cutting tools have to be changed under difficult working conditions. Temperature is high and the work is strenuous. Work is often carried out under increased atmospheric pressure to ward off water ingress. Workers are at a very high risk.Aim:To evaluate heat stress during hyperbaric intervention on TBM during Chennai Metro Rail construction.Methodology:One hundred and eighty-eight miners after a thorough medical examination worked under increased atmospheric pressure for more than 45,000 man hours. Mitigating actions to protect workers by reducing temperature and increasing ventilation. Medical monitoring was done to identify and treat potential victims.Results:52° C was the highest temperature recorded. Most times work was carried out at a temperature range of 34–45° C.Conclusions:Motivations of monetary gains, reduced working hours, and food supplements played a major role in work execution without any untoward incidence.

Heat indicators of oxidative stress, inflammation and metal transport show dependence of cadmium pollution history in the liver of female zebrafish

Environmental stressors such as high temperature and metal exposure may occur sequentially, simultaneously, previously in aquatic ecosystems. However, information about whether responses to high temperature depend on Cd exposure history is still unknown in fish. Zebrafish were exposed to 0 (group 1), 2.5 (group 2) and 5μg/L (group 3) cadmium (Cd) for 10 weeks, and then each group was subjected to Cd-free water maintained at 26°C and 32°C for 7days respectively. 26 indicators were used to compare differences between 26°C and 32°C in the liver of female zebrafish, including 5 biochemical indicators (activity of Cu/Zn-SOD, CAT and iNOS; LPO; MT protein), 8 molecular indicators of oxidative stress (mRNA levels of Nrf2, Cu/Zn-SOD, CAT, HSF1, HSF2, HSP70, MTF-1 and MT), 5 molecular indicators of inflammation (mRNA levels of IL-6, IL-1β, TNF-α, iNOS and NF-κB), 8 molecular indicators of metal transport (mRNA levels of, ZnT1, ZnT5, ZIP8, ZIP10, ATP7A, ATP7B and CTR1). All biochemical indicators were unchanged in group 1 and changed in group 2 and 3. Contrarily, differences were observed in almost all of molecular indicators of inflammation and metal transport in group 1, about half in group 2, and few in group 3. We also found that all molecular indicators of oxidative stress in group 2 and fewer in group 1 and 3 were significantly affected by heat. Our data indicated that heat indicators of oxidative stress, inflammation and metal transport showed dependence of previous cadmium exposure in the liver of zebrafish, emphasizing metal pollution history should be carefully considered when evaluating heat stress in fish.

Evaluation for heat stress tolerance in durum wheat genotypes using stress tolerance indices

ABSTRACTHeat stress is a major environmental stress limiting wheat productivity in most cereal growing areas of the world. The objective of this study was to evaluate heat stress tolerance in durum wheat (Triticum turgidum var. durum) genotypes. For this purpose, 45 genotypes were grown during two growing seasons (2012–2013 and 2013–2014) under non-stress (normal sowing) and heat-stress (late sowing) conditions. The heat tolerance indices were calculated based on grain yield under normal sowing (Yp) and late sowing (Ys) conditions. Results of combined analysis of variance showed the significant influences of heat stress on grain yield as well as significant differences among genotypes for grain yield and the indices. Results of correlation coefficients and multivariate analyses revealed that the stress tolerance index (STI), geometric mean productivity and mean productivity (MP) indices were the most profitable criteria for selection of heat tolerant and high yielding genotypes. Using STI, GMP and MP, the genotypes G29, G41 and G10 were found to be the best genotypes with relatively high yield and suitable for both normal and heat stressed conditions. Based on biplot analysis using Yp, Ys and the indices, it was possible to identify superior genotypes across the conditions.

Occupational heat stress assessment and protective strategies in the context of climate change

Global warming will unquestionably increase the impact of heat on individuals who work in already hot workplaces in hot climate areas. The increasing prevalence of this environmental health risk requires the improvement of assessment methods linked to meteorological data. Such new methods will help to reveal the size of the problem and design appropriate interventions at individual, workplace and societal level. The evaluation of occupational heat stress requires measurement of four thermal climate factors (air temperature, humidity, air velocity and heat radiation); available weather station data may serve this purpose. However, the use of meteorological data for occupational heat stress assessment is limited because weather stations do not traditionally and directly measure some important climate factors, e.g. solar radiation. In addition, local workplace environmental conditions such as local heat sources, metabolic heat production within the human body, and clothing properties, all affect the exchange of heat between the body and the environment. A robust occupational heat stress index should properly address all these factors. This article reviews and highlights a number of selected heat stress indices, indicating their advantages and disadvantages in relation to meteorological data, local workplace environments, body heat production and the use of protective clothing. These heat stress and heat strain indices include Wet Bulb Globe Temperature, Discomfort Index, Predicted Heat Strain index, and Universal Thermal Climate Index. In some cases, individuals may be monitored for heat strain through physiological measurements and medical supervision prior to and during exposure. Relevant protective and preventive strategies for alleviating heat strain are also reviewed and proposed.

Study on environmental indices and heat tolerance tests in hair sheep.

The ability to predict the effects of climatic factors on animals and their adaptability is important for livestock production. The aim of the present study was to analyze whether existing indices are suitable for evaluating heat stress in Santa Ines and Morada Nova sheep, which are locally adapted hair sheep breeds from northeastern Brazil, and if the limits used to classify thermal stress are suitable for these breeds. Therefore, climatic, physiological, and physical parameters, as well as thermographic images, were collected in 26 sheep, 1 1/2years old, from two genetic groups (Santa Ines 12 males and 4 females; Morada Nov. 7 males and 3 females) for 3days in both morning (4:00 a.m.) and afternoon (2:00 p.m.) with six repetitions, totalizing 156 repetitions. Statistical analysis included correlations and broken-line regressions. Iberia and Benezra indices were the tolerance tests that best correlated with the assessed parameters. High correlations between environmental indices and rectal or skin surface temperatures was observed, which indicates that these indices can be used for Santa Ines and Morada Nova sheep raised in central Brazil. However, some indicative values of thermal discomfort are different from the existing classification. Therefore, in order to classify appropriately, the model used needs to be carefully studied, because these classifying values can vary according to the species and model. Further research is necessary to establish indicators of thermal stress for sheep breeds raised in the region.

Heat stress evaluation at the working face in hot coal mines using an improved thermos physiological model

Heat stress evaluation at the working face in hot coal mines using an improved thermos physiological model

Evaluation of heat stress on Tarentaise and Holstein cow performance in the Mediterranean climate

This study was undertaken to first quantify the effect of heat stress on milk yield and components of Tarentaise in comparison to Holstein cows. A dataset of 16,143 monthly individual records of production traits was collected for 435 Tarentaise and 543 Holstein cows from 21 farms in Tunisia (2009 to 2014). This dataset was merged with meteorological data from 5 public stations relative to the 21 farms. The temperature-humidity index (THI), calculated as a combination of ambient temperature and relative humidity, was used to characterize heat stress. When the THI increased from an average value of 53.7 in winter to 75.4 in summer, the Holstein and Tarentaise cows decreased their milk production by 0.93 and 0.15kg/day, respectively. Milk fat, protein, and urea content decreased similarly in both breeds (-2.20g/kg, -1.40g/kg, and -14mg/L, respectively), and the milk somatic cell count increased for Holstein cows (+352,000/mL) while decreased for Tarentaise cows (-160,000/mL). The second aim of this study was to describe the relationship between the variations of the milk yields between the summer and the winter (Δ milk yields) and some barn characteristics during the hot season. A survey carried out on 19 of the 21 previous farms permitted to conclude that the closed buildings led to a higher decrease in milk yield between the summer and winter than the open buildings (-1.13 vs. -0.27kg/day). A metallic roof had a more negative impact on Δ milk yields than the other roof types (-1.04 vs. -0.15kg/day).

Validating the Heat Stress Indices for Using In Heavy Work Activities in Hot and Dry Climates.

Necessity of evaluating heat stress in the workplace, require validation of indices and selection optimal index. The present study aimed to assess the precision and validity of some heat stress indices and select the optimum index for using in heavy work activities in hot and dry climates. It carried out on 184 workers from 40 brick kilns workshops in the city of Qom, central Iran (as representative hot and dry climates). After reviewing the working process and evaluation the activity of workers and the type of work, environmental and physiological parameters according to standards recommended by International Organization for Standardization (ISO) including ISO 7243 and ISO 9886 were measured and indices were calculated. Workers engaged in indoor kiln experienced the highest values of natural wet temperature, dry temperature, globe temperature and relative humidity among studied sections (P<0.05). Indoor workplaces had the higher levels of all environmental parameters than outdoors (P=0.0001), except for air velocity. The wet-bulb globe temperature(WBGT) and heat stress index (HSI) indices had the highest correlation with other physiological parameters among the other heat stress indices. Relationship between WBGT index and carotid artery temperature (r=0.49), skin temperature (r=0.319), and oral temperature (r=0.203) was statistically significant (P=0.006). Since WBGT index, as the most applicable index for evaluating heat stress in workplaces is approved by ISO, and due to the positive features of WBGT such as ease of measurement and calculation, and with respect to some limitation in application of HSI; WBGT can be introduced as the most valid empirical index of heat stress in the brick workshops.