The impact of heat waves on mortality in Northwest India

Projection of future heat-related morbidity in three metropolitan prefectures of Japan based on large ensemble simulations of climate change under 2 °C global warming scenarios

Recently, global warming has become a prominent topic, including its impacts on human health. The number of heat illness cases requiring ambulance transport has been strongly linked to increasing temperature and the frequency of heat waves. Thus, a potential increase in the number of cases in the future is a concern for medical resource management. In this study, we estimated the number of heat illness cases in three prefectures of Japan under 2 °C global warming scenarios, approximately corresponding to the 2040s. Based on the population composition, a regression model was used to estimate the number of heat illness cases with an input parameter of time-dependent meteorological ambient temperature or computed thermophysiological response of test subjects in large-scale computation. We generated 504 weather patterns using 2 °C global warming scenarios. The large-scale computational results show that daily amount of sweating increased twice and the core temperature increased by maximum 0.168 °C, suggesting significant heat strain. According to the regression model, the estimated number of heat illness cases in the 2040s of the three prefectures was 1.90 (95%CI: 1.35-2.38) times higher than that in the 2010s. These computational results suggest the need to manage ambulance services and medical resource allocation, including intervention for public awareness of heat illnesses. This issue will be important in other aging societies in near future.

Impact of heatwaves on all-cause mortality in India: A comprehensive multi-city study

BACKGROUND

Heatwaves are expected to increase with climate change, posing a significant threat to population health. In India, with the world's largest population, heatwaves occur annually but have not been comprehensively studied. Accordingly, we evaluated the association between heatwaves and all-cause mortality and quantifying the attributable mortality fraction in India.

METHODS

We obtained all-cause mortality counts for ten cities in India (2008-2019) and estimated daily mean temperatures from satellite data. Our main extreme heatwave was defined as two-consecutive days with an intensity above the 97th annual percentile. We estimated city-specific heatwave associations through generalised additive Poisson regression models, and meta-analysed the associations. We reported effects as the percentage change in daily mortality, with 95% confidence intervals (CI), comparing heatwave vs non-heatwave days. We further evaluated heatwaves using different percentiles (95th, 97th, 99th) for one, two, three and five-consecutive days. We also evaluated the influence of heatwave duration, intensity and timing in the summer season on heatwave mortality, and estimated the number of heatwave-related deaths.

FINDINGS

Among ∼ 3.6 million deaths, we observed that temperatures above 97th percentile for 2-consecutive days was associated with a 14.7 % (95 %CI, 10.3; 19.3) increase in daily mortality. Alternative heatwave definitions with higher percentiles and longer duration resulted in stronger relative risks. Furthermore, we observed stronger associations between heatwaves and mortality with higher heatwave intensity. We estimated that around 1116 deaths annually (95 %CI, 861; 1361) were attributed to heatwaves. Shorter and less intense definitions of heatwaves resulted in a higher estimated burden of heatwave-related deaths.

CONCLUSIONS

We found strong evidence of heatwave impacts on daily mortality. Longer and more intense heatwaves were linked to an increased mortality risk, however, resulted in a lower burden of heatwave-related deaths. Both definitions and the burden associated with each heatwave definition should be incorporated into planning and decision-making processes for policymakers.

Increasing probability of record-population exposure to high temperature and related health-risks in China

Combining the comprehensive effects of temperature and humidity, this study applies a heat stress index to project future population exposure to high temperature and related health-risks over China under different climate change scenarios. Results show that the number of high temperature days, population exposure and their related health-risks will increase significantly in the future compared to the reference period (1985-2014), which is mainly caused by the change of >T99p (the wet bulb globe temperature >99th percentile derived from the reference period). The population effect is absolutely dominant in influencing the decrease in exposure to T90-95p (the wet bulb globe temperature is in the range of (90th, 95th]) and T95-99p (the wet bulb globe temperature is in the range of (95th, 99th]), and the climate effect is the most prominent contributor to the upsurge in exposure to > T99p in most areas. An additional 0.1 billion person-days increase in population exposure to T90-95p, T95-99p and >T99p in a given year is associated with the number of deaths by 1002 (95% CI: 570-1434), 2926 (95% CI: 1783-4069) and 2635 (95% CI: 1345-3925), respectively. Compared with the reference period, total exposure to high temperature under the SSP2-4.5 (SSP5-8.5) scenario will increase to 1.92 (2.01) times in the near-term (2021-2050) and 2.16 (2.35) times in the long-term (2071-2100), which will increase the number of people at heat risk by 1.2266 (95% CI: 0.6341-1.8192) [1.3575 (95% CI: 0.6926-2.0223)] and 1.5885 (95% CI: 0.7869-2.3902) [1.8901 (95% CI:0.9230-2.8572)] million, respectively. Significant geographic variations exist in the changes of exposure and related health-risks. The change is greatest in the southwest and south, whereas it is relatively small in the northeast and north. The findings provide several theoretical references for climate change adaptation.

Acute and chronic impacts of heat stress on planetary health

Heat waves are increasing in intensity, frequency, and duration causing significant heat stress in all living organisms. Heat stress has multiple negative effects on plants affecting photosynthesis, respiration, growth, development, and reproduction. It also impacts animals leading to physiological and behavioral alterations, such as reduced caloric intake, increased water intake, and decreased reproduction and growth. In humans, epidemiological studies have shown that heat waves are associated with increased morbidity and mortality. There are many biological effects of heat stress (structural changes, enzyme function disruption, damage through reactive oxygen or nitrogen species). While plants and animals can mitigate some of these effects through adaptive mechanisms such as the generation of heat shock proteins, antioxidants, stress granules, and others, these mechanisms may likely be inadequate with further global warming. This review summarizes the effects of heat stress on plants and animals and the adaptative mechanisms that have evolved to counteract this stress.

Characterization and outlook of climatic hazards in an agricultural area of Pakistan

Many dimensions of human life and the environment are vulnerable to anthropogenic climate change and the hazards associated with it. There are several indices and metrics to quantify climate hazards that can inform preparedness and planning at different levels e.g., global, regional, national, and local. This study uses biased corrected climate projections of temperature and precipitation to compute characteristics of potential climate hazards that are pronounced in the Gomal Zam Dam Command Area (GZDCA)- an irrigated agricultural area in Khyber Pakhtunkhwa province of Pakistan. The results answer the question of what the future holds in the GZDCA regarding climate hazards of heatwaves, heavy precipitation, and agricultural drought. The results of heatwaves and agricultural drought present an alarming future and call for immediate actions for preparedness and adaptation. The magnitude of drought indices for the future is correlated with the crop yield response based on AquaCrop model simulations with observed climate data being used as input. This correlation provides insight into the suitability of various drought indices for agricultural drought characterization. The results elaborate on how the yield of wheat crop grown in a typical setting common in the South Asian region respond to the magnitude of drought indices. The findings of this study inform the planning process for changing climate and expected climate hazards in the GZDCA. Analyzing climate hazards for the future at the local level (administrative districts or contiguous agricultural areas) might be a more efficient approach for climate resilience due to its specificity and enhanced focus on the context.

Mortality Risk Related to Heatwaves in Dezful City, Southwest of Iran

BACKGROUND

We aimed to evaluate the impact of heatwaves on daily deaths due to non-accidental, cardiovascular and respiratory causes in the city of Dezful in Iran from 2013 to 2019.

METHOD

We collected daily ambient temperature and mortality and defined 2 types of heatwaves by combining daily temperature ⩾90th in each month of the study period or since 30 years with duration ⩾2 and 3 days. We used a distributed lag non-linear model to study the association between each type of heatwave definition, and deaths due to non-accidental, cardiovascular and respiratory causes with lags up to 13 days.

RESULTS

There was no discernible correlation in this area, despite the fact that heatwaves raised the risk of death from cardiovascular causes and lowered the risk from respiratory causes. On the other hand, the risk of total non-accidental mortality on days with the heatwaves is significantly higher than normal days. In main effects, the heatwaves have a significant relationship with the risk of total non-accidental mortality (in the first heatwave definition, Cumulative Excess Risk (CER) in lag_0-2 was 10.4 and in second heatwave definition, CER values in lag_{0, 0-2, and 0-6} were 12.4, 29.2, and 38.8 respectively). Also, in added effects, heatwaves have a significant relationship with the risk of total non-accidental mortality (in the first heatwave definition, CER in lag_{0 and 0-2} were 1.79 and 4.11 and in the second heatwave definition, CER values in lag_{0, 0-2, and 0-6} were 7.76, 18.35 and 24.87 respectively). In addition, heatwaves appeared to contribute to a cumulative excess risk of non-accidental death among the male group as well as the older adults.

CONCLUSION

However, the results showed that heatwaves could have detrimental effects on health, even in populations accustomed to the extreme heat. Therefore, early warning systems which monitor heatwaves should provide the necessary warnings to the population, especially the most vulnerable groups.

Energy Efficiency through the Implementation of an AI Model to Predict Room Occupancy Based on Thermal Comfort Parameters

Room occupancy prediction based on indoor environmental quality may be the breakthrough to ensure energy efficiency and establish an interior ambience tailored to each user. Identifying whether temperature, humidity, lighting, and CO2 levels may be used as efficient predictors of room occupancy accuracy is needed to help designers better utilize the readings and data collected in order to improve interior design, in an effort to better suit users. It also aims to help in energy efficiency and saving in an ever-increasing energy crisis and dangerous levels of climate change. This paper evaluated the accuracy of room occupancy recognition using a dataset with diverse amounts of light, CO2, and humidity. As classification algorithms, K-nearest neighbors (KNN), hybrid Adam optimizer–artificial neural network–back-propagation network (AO–ANN (BP)), and decision trees (DT) were used. Furthermore, this research is based on machine learning interpretability methodologies. Shapley additive explanations (SHAP) improve interpretability by estimating the significance values for each feature for classifiers applied. The results indicate that the KNN performs better than the DT and AO-ANN (BP) classification models have 99.5%. Though the two classifiers are designed to evaluate variations in interpretations, we must ensure that they have accurate detection. The results show that SHAP provides successful implementation following these metrics, with differences detected amongst classifier models that support the assumption that model complexity plays a significant role when predictability is taken into account.

Individually experienced heat stress among elderly residents of an urban slum and rural village in India

The elderly are one of the most vulnerable groups to heat-related illnesses and mortality. In tropical countries like India, where heat waves have increased in frequency and severity, few studies have focused on the level of stress experienced by the elderly. The study presented here included 130 elderly residents of Kolkata slums and 180 elderly residents of rural villages about 75 km south of Kolkata. It used miniature monitoring devices to continuously measure temperature, humidity, and heat index experienced during everyday activities over 24-h study periods, during hot summer months. In the Kolkata slum, construction materials and the urban heat island effect combined to create hotter indoor than outdoor conditions throughout the day, and particularly at night. As a result, elderly slum residents were 4.3 times more likely to experience dangerous heat index levels (≥ 45°C) compared to rural village elderly. In both locations, the median 24-h heat indexes of active elderly were up to 2°C higher than inactive/sedentary elderly (F = 25.479, p < 0.001). Among Kolkata slums residents, there were no significant gender differences in heat exposure during the day or night, but in the rural village, elderly women were 4 times more likely to experience dangerous heat index levels during the hottest times of the day compared to elderly men. Given the decline in thermoregulatory capacity associated with aging and the increasing severity of extreme summer heat in India, these results forecast a growing public health challenge that will require both scientific and government attention.

Heatwaves in South Asia: Characterization, Consequences on Human Health, and Adaptation Strategies

South Asia, with more than one-fifth of the world’s population, is highly vulnerable to heatwaves and associated health consequences. The population experiences considerably higher residential vulnerability due to limited infrastructural capacities, economic resources, and health and environmental quality deficiencies. However, a limited number of studies are available from the region to account for the health effects of heatwaves. Therefore, this study has conducted a comprehensive review to characterize heatwaves across South Asian countries. The review explicitly identifies the population’s vulnerability to heatwaves during recent years and heatwave management policies in the region. The literature review suggests increased heat-related deaths in most South Asian countries, with few exceptions. In addition, the analysis of historical temperature records identified an upward trend in annual average temperature across the South Asian countries. The study highlights various heatwave definitions that have been used in the region to facilitate comparative evidence. The review of policies identified that only a few South Asian countries have functional heatwave management plans and majorly lack community and residential preparedness for heatwaves. Therefore, this study identifies potential community- and residential-based adaptation strategies to mitigate heat discomfort. As prospective solutions, the study recommends adaptation strategies such as blue–green spaces, indoor passive cooling, infrastructural adjustments, heat action plans, etc. However, such adaptation measures require a holistic amalgamation of different stakeholders to fabricate heatwave-resilient cities.

Mortality risk attributable to high and low ambient temperature in Pune city, India: A time series analysis from 2004 to 2012

BACKGROUND

Exposure to high and low ambient temperatures is associated with morbidity and mortality across the globe. Most of these studies assessing the effects of non-optimum temperatures on health and have been conducted in the developed world, whereas in India, the limited evidence on ambient temperature and health risks and has focused mostly on the effects of heat waves. Here we quantify short term association between all temperatures and mortality in urban Pune, India.

METHODS

We applied a time series regression model to derive temperature-mortality associations based on daily mean temperature and all-cause mortality records of Pune city from year January 2004 to December 2012. We estimated high and low temperature-mortality relationships by using standard time series quasi-Poisson regression in conjunction with a distributed lag non-linear model (DLNM). We calculated temperature attributable mortality fractions for total heat and total cold.

FINDINGS

The analysis provides estimates of the total mortality burden attributable to ambient temperature. Overall, 6∙5% [95%CI 1.76-11∙43] of deaths registered in the observational period were attributed to non-optimal temperatures, cold effect was greater 5.72% [95%CI 0∙70-10∙06] than heat 0∙84% [0∙35-1∙34]. The gender stratified analysis revealed that the highest burden among men both for heat and cold.

CONCLUSION

Non-optimal temperatures are associated with a substantial mortality burden. Our findings could benefit national, and local communities in developing preparedness and prevention strategies to reduce weather-related impacts immediately due to climate change.

A randomized cross-over trial investigating differences in 24-h personal air and skin temperatures using wearable sensors between two climatologically contrasting settings

The influence of elevated air temperatures recorded in various urban microenvironments in adversely impacting biologically relevant disease end points has not yet been extensively tackled. This study is a post hoc analysis of the TEMP pilot trial, a randomized 2 × 2 cross-over trial that examined changes in metabolic and stress hormonal profiles of healthy adults in two settings (urban vs. rural) with distinctly different climatological characteristics during the Mediterranean summer. This analysis aimed to study the association between the 24-h personal air or skin temperature sensor measurements and the diary-based location type (indoors vs. outdoors) in urban (seaside) vs. rural (higher in altitude) microenvironments. Out of 41 eligible participants, a total of 37 participants were included in this post-hoc TEMP trial analysis. Wearable sensors recorded personal air temperature, skin temperature, and activity (as a surrogate marker of physical activity) in each setting, while a time-stamped personal diary recorded the types of indoor or outdoor activities. Temperature peaks during the 24-h sampling period were detected using a peak finding algorithm. Mixed effect logistic regression models were fitted for the odds of participant location (being indoors vs. outdoors) as a function of setting (urban vs. rural) and sensor-based personal temperature data (either raw temperature values or number of temperature peaks). During the study period (July-end of September), median [interquartile range, IQR] personal air temperature in the rural (higher altitude) settings was 1.5 °C lower than that in the urban settings (27.1 °C [25.4, 29.2] vs. 28.6 °C [27.1, 30.5], p < 0.001), being consistent with the Mediterranean climate. Median [IQR] personal air temperature in indoor (micro)environments was lower than those in outdoors (28.0 °C [26.4, 30.3] vs 28.5 °C [26.8, 30.7], p < 0.001). However, median [IQR] skin temperature was higher in indoor (micro)environments vs. outdoors (34.8 °C [34.0, 35.6] and 33.9 °C [32.9, 34.8], p < 0.001) and the number of both personal air and skin temperature peaks was higher indoors compared to outdoors (median [IQR] 3.0 [2.0,4.0] vs 1.0 [1.0,1.3], p < 0.007, for the skin sensors). A significant association between the number of temperature peaks and indoor location types was observed with either the personal air sensor (OR 3.1; 95% CI 1.2-8.2; p = 0.02) or the skin sensor (OR 3.7; 95% CI 1.4-9.9; p = 0.01), suggesting higher number of indoor air temperature fluctuations. Amidst the global climate crisis, more population health studies or personalized medicine approaches that utilize continuous tracking of individual-level air/skin temperatures in both indoor/outdoor locations would be warranted, if we were to better characterize the disease phenotype in response to climate change manifestations.

Using machine learning to examine street green space types at a high spatial resolution: Application in Los Angeles County on socioeconomic disparities in exposure

BACKGROUND

Compared to commonly-used green space indicators from downward-facing satellite imagery, street view-based green space may capture different types of green space and represent how environments are perceived and experienced by people on the ground, which is important to elucidate the underlying mechanisms linking green space and health.

OBJECTIVES

This study aimed to evaluate machine learning models that can classify the type of vegetation (i.e., tree, low-lying vegetation, grass) from street view images; and to investigate the associations between street green space and socioeconomic (SES) factors, in Los Angeles County, California.

METHODS

SES variables were obtained from the CalEnviroScreen3.0 dataset. Microsoft Bing Maps images in conjunction with deep learning were used to measure total and types of street view green space, which were compared to normalized difference vegetation index (NDVI) as commonly-used satellite-based green space measure. Generalized linear mixed model was used to examine associations between green space and census tract SES, adjusting for population density and rural/urban status.

RESULTS

The accuracy of the deep learning model was high with 92.5% mean intersection over union. NDVI were moderately correlated with total street view-based green space and tree, and weakly correlated with low-lying vegetation and grass. Total and three types of green space showed significant negative associations with neighborhood SES. The percentage of total green space decreased by 2.62 [95% confidence interval (CI): -3.02, -2.21, p < 0.001] with each interquartile range increase in CalEnviroScreen3.0 score. Disadvantaged communities contained approximately 5% less average street green space than other communities.

CONCLUSION

Street view imagery coupled with deep learning approach can accurately and efficiently measure eye-level street green space and distinguish vegetation types. In Los Angeles County, disadvantaged communities had substantively less street green space. Governments and urban planners need to consider the type and visibility of street green space from pedestrian's perspective.

Does Ethnic Diversity Impact on Risk Perceptions, Preparedness, and Management of Heat Waves?

Detrimental health impacts of heatwaves, including excess mortality, are increasing worldwide. To assess risk perceptions, protective knowledge and behaviors concerning heatwaves in Israel, a study was initiated, comparing attitudes of majority (Jewish) and minority (Arab) populations. A quantitative survey was disseminated through an internet panel, to a representative sample of 556 individuals (79% Jews; 21% Arabs). Overall, 74% consider heatwaves a problem, 93% believe that heatwaves' frequencies will increase, 27% are very concerned about the effects of heatwaves. Higher levels of awareness to heatwaves were found among Jewish compared to Arab respondents; 90 vs. 77% (respectively) could name heatwaves' symptoms (p < 0.001); 81 vs. 56% (respectively) reported knowing how to protect themselves (p < 0.001); 74 vs. 47% (respectively) reported knowing what to do when someone suffers from heat stroke (p < 0.001). Arab compared to Jewish respondents presented higher levels of concern about heatwaves' effects (3.22 vs. 3.09 respectively; t −2.25, p = 0.03), while knowledge of protective measures was higher among Jews compared to Arabs (3.67 vs. 3.56 t = 2.13 p = 0.04). A crucial component of enhancing preparedness to heatwaves is empowerment of minority as well as majority groups, to strengthen their capacity to implement protective behavior and elevate their self-belief in their individual ability and fortitude.

Association between ambient temperature and heat waves with mortality in South Asia: Systematic review and meta-analysis

BACKGROUND

South Asia is highly vulnerable to climate change and is projected to experience some of the highest increases in average annual temperatures throughout the century. Although the adverse impacts of ambient temperature on human health have been extensively documented in the literature, only a limited number of studies have focused on populations in this region.

OBJECTIVES

Our aim was to systematically review the current state and quality of available evidence on the direct relationship between ambient temperature and heat waves and all-cause mortality in South Asia.

METHODS

The databases Pubmed, Web of Science, Scopus and Embase were searched from 1990 to 2020 for relevant observational quantitative studies. We applied the Navigation Guide methodology to assess the strength of the evidence and performed a meta-analysis based on a novel approach that allows for combining nonlinear exposure-response associations without access to data from individual studies.

RESULTS

From the 6,759 screened papers, 27 were included in the qualitative synthesis and five in a meta-analysis. Studies reported an association of all-cause mortality with heat wave episodes and both high and low daily temperatures. The meta-analysis showed a U-shaped pattern, with increasing mortality for both high and low temperatures, but a statistically significant association was found only at higher temperatures - above 31° C for lag 0-1 days and above 34° C for lag 0-13 days. Effects were found to vary with cause of death, age, sex, location (urban vs. rural), level of education and socio-economic status, but the profile of vulnerabilities was somewhat inconsistent and based on a limited number of studies. Overall, the strength of the evidence for ambient temperature as a risk factor for all-cause mortality was judged as limited and for heat wave episodes as inadequate.

CONCLUSIONS

The evidence base on temperature impacts on mortality in South Asia is limited due to the small number of studies, their skewed geographical distribution and methodological weaknesses. Understanding the main determinants of the temperature-mortality association as well as how these may evolve in the future in a dynamic region such as South Asia will be an important area for future research. Studies on viable adaptation options to high temperatures for a region that is a hotspot for climate vulnerability, urbanisation and population growth are also needed.

PoDIT: Portable Device for Indoor Temperature Stabilization: Concept and Theoretical Performance Assessment

This work introduces the concept of a new Portable Device for Indoor Temperature Stabilization (PoDIT), to be considered as a low-cost, quick and easy to implement remediation strategy when, for social, economic, or technical reasons, the improvement of the building envelope and/or the adoption of air conditioning are not possible. The main goal is to attenuate the maximum indoor temperature during summer and/or heat waves. The system, which is modular, consists of a certain mass of encaged phase change material (PCM) that stays indoors during the daytime and is transported to the outdoors (e.g., a balcony) during the night to discharge the heat accumulated during the daytime. Both natural convection and forced convection variants were considered. The results showed that, in the configurations and for the reference room and weather considered, the adopting 4 modules of the device can lead to reductions in the maximum room air temperature close to 3 °C, with natural convection. Adopting a fan to impose forced convection at the surfaces of the device can lead to temperature attenuations in excess of 4 °C, as it ensures full solid–liquid commuting and therefore optimal use of the PCM thermal storage capability.

Heat Wave and Elderly Mortality: Historical Analysis and Future Projection for Metropolitan Region of São Paulo, Brazil

The Metropolitan Region of Sao Paulo (MRSP) is one of the main regions of Brazil that in recent years has shown an increase in the number of days with heat waves, mainly affecting the health of the most sensitive populations, such as the elderly. In this study, we identified the heat waves in the MRSP using three different definitions regarding the maximum daily temperature threshold. To analyze the impact of heat waves on elderly mortality, we used distributed lag nonlinear models (dlnm) and we quantified the heat wave-related excess mortality of elderly people from 1985 to 2005 and made projections for the near future (2030 to 2050) and the distant future (2079–2099) under the climate change scenarios RCP4.5 and RCP8.5 (RCP: Representative Concentration Paths). An important aspect of this research is that for the projections we take into account two assumptions: non-adaptation and adaptation to the future climate. Our projections show that the heat wave-related excess of elderly mortality will increase in the future, being highest when we consider no adaptation, mainly from cardiovascular diseases in women (up to 587 deaths per 100,000 inhabitants per year). This study can be used for public policies to implement preventive and adaptive measures in the MRSP.

Keeping older individuals cool in hot and moderately humid conditions: wetted clothing with and without an electric fan

The present study evaluated whether wearing a water-soaked t-shirt, with or without electric fan use, mitigates thermal and cardiovascular strain in older individuals exposed to hot and moderately humid conditions. Nine healthy older individuals (68 ± 4 yr; five women) completed three 120-min heat exposures (42.4 ± 0.2°C, 34.2 ± 0.9% relative humidity) on separate days while wearing a dry t-shirt (CON), a t-shirt soaked with 500 ml of tap water (WET), or a t-shirt soaked with 500 ml of tap water while facing an electric fan (2.4 ± 0.4 m/s; WET+FAN). Measurements included core and skin temperatures, evaporative mass losses, heart rate, and blood pressure. In the WET condition, elevations in core temperature were attenuated compared with DRY from 30 to 120 min and compared with WET+FAN from 30 to 90 min (P < 0.05). Evaporative mass losses (inclusive of sweat and water losses from the shirt) were greatest in WET+FAN, followed by WET, and then DRY (P < 0.01). Sweat losses were lowest in WET, followed by DRY, and then WET+FAN (P < 0.01). Heart rate was lower only at 60 min in WET versus DRY (P = 0.01). No differences in mean arterial pressure were observed (P = 0.51). In conclusion, wearing a water-soaked t-shirt without, but not with, electric fan use is an effective heat management strategy to mitigate thermal strain and lower sweat losses in older individuals exposed to hot and moderately humid conditions.NEW & NOTEWORTHY In older individuals exposed to hot and moderately humid environments, electric fan use coupled with a water-soaked t-shirt exacerbates sweat losses without mitigating heat strain compared with a dry t-shirt. However, wearing a water-soaked t-shirt without fan use reduces sweat losses and attenuates heat strain compared with a dry t-shirt and a fan/water-soaked t-shirt combination. These findings suggest wearing a water-soaked t-shirt is an effective heat-management strategy for older individuals during heat waves when air conditioning is inaccessible.

Future Heat Waves in Different European Capitals Based on Climate Change Indicators

Changes in the frequency and intensity of heat waves have shown substantial negative impacts on public health. At the same time, climate change towards increasing air temperatures throughout Europe will foster such extreme events, leading to the population being more exposed to them and societies becoming more vulnerable. Based on two climate change scenarios (Representative Concentration Pathway 4.5 and 8.5) we analysed the frequency and intensity of heat waves for three capital cities in Europe representing a North-South transect (London, Luxembourg, Rome). We used indices proposed by the Expert Team on Sector-Specific Climate Indices of the World Meteorological Organization to analyze the number of heat waves, the number of days that contribute to heat waves, the length of the longest heat waves, as well as the mean temperature during heat waves. The threshold for the definition of heat waves is calculated based on a reference period of 30 years for each of the three cities, allowing for a direct comparison of the projected changes between the cities. Changes in the projected air temperature between a reference period (1971-2000) and three future periods (2001-2030 near future, 2031-2060 middle future, and 2061-2090 far future) are statistically significant for all three cities and both emission scenarios. Considerable similarities could be identified for the different heat wave indices. This directly affects the risk of the exposed population and might also negatively influence food security and water supply.