Awareness of Fluid Losses Does Not Impact Thirst during Exercise in the Heat: A Double-Blind, Cross-Over Study

Background: Thirst has been used as an indicator of dehydration; however, as a perception, we hypothesized that it could be affected by received information related to fluid losses. The purpose of this study was to identify whether awareness of water loss can impact thirst perception during exercise in the heat. Methods: Eleven males participated in two sessions in random order, receiving true or false information about their fluid losses every 30 min. Thirst perception (TP), actual dehydration, stomach fullness, and heat perception were measured every 30 min during intermittent exercise until dehydrated by ~4% body mass (BM). Post exercise, they ingested water ad libitum for 30 min. Results: Pre-exercise BM, TP, and hydration status were not different between sessions (p > 0.05). As dehydration progressed during exercise, TP increased significantly (p = 0.001), but it was the same for both sessions (p = 0.447). Post-exercise water ingestion was almost identical (p = 0.949) in the two sessions. Conclusion: In this study, thirst was a good indicator of fluid needs during exercise in the heat when no fluid was ingested, regardless of receiving true or false water loss information.

Heat Shock Signaling in Land Plants: From Plasma Membrane Sensing to the Transcription of Small Heat Shock Proteins

Heat stress events are major factors limiting crop productivity. During summer days, land plants must anticipate in a timely manner upcoming mild and severe temperature. They respond by accumulating protective heat-shock proteins (HSPs), conferring acquired thermotolerance. All organisms synthetize HSPs; many of which are members of the conserved chaperones families. This review describes recent advances in plant temperature sensing, signaling, and response. We highlight the pathway from heat perception by the plasma membrane through calcium channels, such as cyclic nucleotide-gated channels, to the activation of the heat-shock transcription factors (HSFs). An unclear cellular signal activates HSFs, which act as essential regulators. In particular, the HSFA subfamily can bind heat shock elements in HSP promoters and could mediate the dissociation of bound histones, leading to HSPs transcription. Although plants can modulate their transcriptome, proteome, and metabolome to protect the cellular machinery, HSP chaperones prevent, use, and revert the formation of misfolded proteins, thereby avoiding heat-induced cell death. Remarkably, the HSP20 family is mostly tightly repressed at low temperature, suggesting that a costly mechanism can become detrimental under unnecessary conditions. Here, the role of HSP20s in response to HS and their possible deleterious expression at non-HS temperatures is discussed.

Heat Perception and Coping Strategies: A Structured Interview-Based Study of Elderly People in Cologne, Germany

The transdisciplinary project “Heat-Health Action Plan for Elderly People in Cologne” addresses the most heat-vulnerable risk group, people over 65 years of age. A quantitative study aimed to better understand heat perception and coping strategies of elderly people during heat waves to inform heat-health action plans. We conducted a representative quantitative survey via structured interviews with 258 randomly chosen people over 65 years old, living in their own homes in four areas of Cologne, Germany. These areas varied, both in terms of social status and heat strain. Data regarding demographics, health status, coping strategies, and heat perception were collected in personal interviews from August to October 2019. The majority of the participants perceived heat strain as moderate to very challenging. Women, people with a lower monthly income, and those with a lower health status found the heat more challenging. We found that participants adapted to heat with a number of body-related, home-protective, and activity-related coping strategies. The number of coping strategies was associated with perceived personal heat strain. There is a definite underuse of water-related heat adaption strategies among the elderly. This is of increasing relevance, as rising heat impact will lead to more heat-related geriatric morbidity. Our results are seminal to inform elderly-specific, socio-adapted local heat-health action plans.

Ownership and utilization of bed nets and reasons for use or non-use of bed nets among community members at risk of malaria along the Thai-Myanmar border

Background With the goal for malaria elimination in Thailand set for 2024, increased coverage and utilization of bed net, especially insecticide-treated net (ITN) or long-lasting insecticidal net (LLIN) is a key strategy. This study aims to provide the necessary information about bed net ownership and utilization among the population at risk of malaria living along the Thai-Myanmar border in Tak province. Methods A cross-sectional study was conducted using a mixed-method approach in 331 households from 5 hamlets in the villages of the Thai-Myanmar border. The research tools included a questionnaire, bed net inspection, and semi-structured interviews. Logistic regression was used to explore the sociodemographic factors associated with bed net utilization. The qualitative analysis employed a thematic analysis approach. Results This survey found that 98.5% of households had at least one bed net per household, and 74.3% had at least one ITN/LLIN. However, only 30.8% of households reached the standard policy set by the Minister of Public Health of one ITN/LLINs per two persons. Most residents used bed net (92.1% used in the previous night and 80.9% used every day). For those using bed nets, however, 61.9% used ITNs or LLINs the night before and 53.1% used them every day. Nonetheless, the usage rates of bed nets (any type) in the previous night among children and pregnant women were high, reaching 95.3% and 90.0%, respectively. Seven explanatory variables showed statistically significant associations with bed net use every day, including: “not staying overnight in the forest or the field”, “sleeping pattern based on gender”, “sufficient numbers of bed nets to cover all sleeping spaces”, “preference for free bed nets”, “age”, “gender”, and “SES score” showed statistically significant association with bed net use every day. The major reasons for the regular use of bed nets in both household and the forest were to prevent mosquito biting. The reasons for not using bednets in the household were discomfort feelings from heat, perception of unnecessity due to low mosquito density, whereas the reason for not using bed nets in the forest was inconvenience. Conclusion Despite that overall coverage and usage of bed nets was high, only one third reached the standard level specified by the policy. Overnight in the forest, the dissatisfaction with the quality of free bed nets, insufficient number of bed nets, sleeping alone, male gender, age more than 10 years, low socioeconomic status, discomfort from heat, perception of no benefits of bed nets due to low mosquito density, and inconvenience were factors influencing bed net use. Maintaining high coverage and utility rate of bed nets should be a priority for the malaria high-risk population.

Thermal stress assessment for an Arctic city in summer

Despite the fact, that against the background of global warming the Russian Arctic is still a region with severe winters and cool summers; the likelihood of thermal stress conditions in summer is also increasing. At the same time, urban conditions can significantly affect the human heat perception due to the appearance of the urban heat island effect and other factors. Using the example of the city of Nadym (Yamalo-Nenets Autonomous Okrug), the authors have assessed the possibility of the summer urban heat stress occurrence and analyzed its spatial heterogeneity. The article presents the detailed modeling results of the meteorological regime of the city within the framework of the COSMO-CLM model and the assessment of bioclimatic comfort using the Physiologically Equivalent Temperature (PET) index and Universal Thermal Climate Index (UTCI). During periods of the extremely hot weather events in Nadym, the territory meso- and microclimatic mosaicism clearly manifests itself. In anthropogenically altered territories, the frequency of strong heat stress events can exceed that in the background areas by 1.7 times. Urban planning solutions should take into account not only the climatic resistance of Arctic cities to the winter cold, but also be adapted to the occurrence of summer heat.

STUDY OF WATER ECONOMIZERS OF STEAM BOILERS AND DEVELOPMENT OF MEASURES FOR EXTENDING THEIR OPERATION

The operation of the economizer of the P-50 boiler unit, as well as the conditions of its operation have been studied. The economizer is one of the main components of the boiler unit. It works in very difficult conditions. The quality of the feed water supplied to the drum depends on the operation of the economizer. The thermal calculation of steam boiler type P-50 using different values ​​of feed water temperatures at the inlet to the economizer and different coefficients of excess air in the furnace, identified and analyzed factors that negatively affect the operation of the water economizer to conduct a detailed analysis and development of recommendations to improve the operation of the steam boiler as a whole and separately economizing heating surfaces. As a result of the calculations, the dependences of the heat perception of the economizer on the temperature of the feed water at the inlet to the economizer and the dependence of the excess air on the total volume of combustion products are obtained. The paper considers in detail the possible causes of failure of economizers and factors that have a negative impact on the condition of the metal pipes; proposed recommendations that will increase the service life of economizers until the next repair campaign.

Ownership, utilization, and motivations for use or non-use of bed nets among community members at risk of malaria along the Thai-Myanmar border

Background With the goal for malaria elimination in Thailand set for 2024, increased coverage and utilization of bed net, especially insecticide-treated net (ITN) or long-lasting insecticidal net (LLIN) is a key strategy. This study aims to provide the necessary information about bed net ownership and utilization among the population at risk of malaria living along the Thai-Myanmar border in Tak province. Methods A cross-sectional study was conducted using a mixed-method approach in 331 households from 5 hamlets in the villages of the Thai-Myanmar border. The research tools included a questionnaire, bed net inspection, and semi-structured interviews. Log-binomial regression was used to explore the sociodemographic factors associated with bed net utilization. The qualitative analysis employed a thematic analysis approach. Results This survey found that 98.5% of households had at least one bed net per household, and 74.3% had at least one ITN/LLIN. However, only 30.8% of households reached the standard policy set by the Minister of Public Health of one ITN/LLINs per two persons. Most residents used bed net (92.1% used in the previous night and 80.9% used every day). For those using bed nets, however, 61.9% used ITNs or LLINs the night before and 53.1% used them every day. Nonetheless, the usage rates of bed nets (any type) in the previous night among children and pregnant women were high, reaching 95.3% and 90.0%, respectively. Three explanatory variables including “not stay overnight in the forest”, “preference of free bed nets”, and “sufficient numbers of bed nets to cover all sleeping spaces”, showed statistically significant association with bed net use every day. The major reasons for the regular use of bed nets in both household and the forest were to prevent mosquito biting. The reasons for not using bednets in the household were discomfort feelings from heat, perception of unnecessity due to low mosquito density, whereas the reason for not using bednets in the forest was inconvenience. Conclusion Despite that overall coverage and usage of bed nets was high, only one third reached the standard level specified by the policy. Overnight in the forest, the dissatisfaction with the quality of free bed nets, insufficient number of bed nets, discomfort from heat, perception of no benefits of bed nets due to low mosquito density, and inconvenience were factors influencing bed net use. Maintaining high coverage and utility rate of bed nets should be a priority for the malaria high-risk population.

The temporal and spectral characteristics of expectations and prediction errors in pain and thermoception

In the context of a generative model, such as predictive coding, pain and heat perception can be construed as the integration of expectation and input with their difference denoted as a prediction error. In a previous neuroimaging study (Geuter et al., 2017) we observed an important role of the insula in such a model but could not establish its temporal aspects. Here, we employed electroencephalography to investigate neural representations of predictions and prediction errors in heat and pain processing. Our data show that alpha-to-beta activity was associated with stimulus intensity expectation, followed by a negative modulation of gamma band activity by absolute prediction errors. This is in contrast to prediction errors in visual and auditory perception, which are associated with increased gamma band activity, but is in agreement with observations in working memory and word matching, which show gamma band activity for correct, rather than violated, predictions.

Exploring pedestrian thermal comfort in hot climates

<p>Designing cities for thermal comfort should be a priority in the warming and urbanizing world. As cities continue to break extreme heat records, it is necessary to develop new sensing approaches capable of tracking thermal sensations of actual users of urban spaces. The Influence of built infrastructure on the microclimate at a human scale and residents’ thermal sensations is not well explored, but combining sensing techniques with simultaneous collection of user experiences is a promising research direction to shorten the gap.</p><p>We explored the relationships between the built environment, heat perception, and behavioral coping mechanisms in one of the most heat vulnerable Phoenix neighborhoods. Using Phoenix as an example, where extreme summer temperatures are a norm, can help to address heat challenges of other cities that have started facing temperature extremes in the recent years.</p><p>This study is an experimental citizen science project in which participants helped to create a “heat map” of the neighborhood. Participants were engaged in a 1-hour walk around the neighborhood and recorded their experience in a field guide. A smaller group participated in walking interviews and wore GPS devices and UV meters to gain deeper insights on subjective heat perception and physical body heat accumulation during the walk. Results revealed the differences in heat perception across a variety of urban landscapes. Participants identified preferred and most challenging locations, and gave ideas on what could improve their experience. Combined heart rate, UV exposure and microclimate data mapped in GIS visualized dependencies between the streetscape and physiological conditions of the study participants.</p><p>This project is one of the first to examine the impact of urban environment on dynamic psychological and physiological responses to heat. Using sensing techniques and qualitative research instruments, this research will inform the design changes in the neighborhood that will undergo redevelopment. It can serve as an example for other cities striving to adapt urban microclimates to new extremes.</p>

Impairments to Thermoregulation in the Elderly During Heat Exposure Events

Heat waves represent a public health risk to elderly people, and typically result in an increased rate of hospital admissions and deaths. Studies of thermoregulation in this cohort have generally focused on single elements such as sweating capacity. Sweating capacity and skin blood flow reduce with age, reducing ability to dissipate heat. Perception of effort during heat exposure is emerging as an area that needs further investigation as the elderly appear to lack the ability to adequately perceive increased physiological strain during heat exposure. The role of the gut and endotoxemia in heat stress has received attention in young adults, while the elderly population has been neglected. This shortcoming offers another potential avenue for identifying effective integrated health interventions to reduce heat illnesses. Increasing numbers of elderly individuals in populations worldwide are likely to increase the incidence of heat wave-induced deaths if adequate interventions are not developed, evaluated, and implemented. In this narrative-style review we identify and discuss health-related interventions for reducing the impact of heat illnesses in the elderly.