Heat Stroke Research Articles

Heat-related mortality and ambulance transport after a power outage in the Tokyo metropolitan area.

Air conditioners can prevent heat-related illness and mortality, but the increased use of air conditioners may enhance susceptibility to heat-related illnesses during large-scale power failures. Here, we examined the risks of heat-related illness ambulance transport (HIAT) and mortality associated with typhoon-related electricity reduction (ER) in the summer months in the Tokyo metropolitan area. We conducted event study analyses to compare temperature-HIAT and mortality associations before and after the power outage (July to September 2019). To better understand the role of temperature during the power outage, we then examined whether the temperature-HIAT and mortality associations were modified by different power outage levels (0%, 10%, and 20% ER). We computed the ratios of relative risks to compare the risks associated with various ER values to the risks associated without ER. We analyzed the data of 14,912 HIAT cases and 74,064 deaths. Overall, 93,200 power outage cases were observed when the typhoon hit. Event study results showed that the incidence rate ratio was 2.01 (95% confidence interval [CI] = 1.42, 2.84) with effects enduring up to 6 days, and 1.11 (95% CI = 1.02, 1.22) for mortality on the first 3 days after the typhoon hit. Comparing 20% to 0% ER, the ratios of relative risks of heat exposure were 2.32 (95% CI = 1.41, 3.82) for HIAT and 0.95 (95% CI = 0.75, 1.22) for mortality. A 20% ER was associated with a two-fold greater risk of HIAT because of summer heat during the power outage, but there was little evidence for the association with all-cause mortality.

IJCM_314A: Risk perceptions of heat related illnesses, assessing vulnerability and adaptive capacity of brick- kiln workers in a rural Puducherry: A Cross-Sectional Study

Background: Heat is one of the physical hazards that can cause health problems in the workplace, Brick field workers are widely exposed to risk factors for heat-related illnesses. Knowledge, attitudes, and practices (KAP) are three of the most important means of preventing such illnesses. Objectives: To determine the predictors of risk perception and to assess the vulnerability and adaptive capacity regarding heat-related illness among brick field workers in Rural Puducherry. Methodology: A cross-sectional study was conducted from March to June (2023). A total of 280 Brickfield workers were recruited from five rural commune areas of Puducherry, using the Multistage random sampling method. The data was collected on demographic characteristics, risk perception and spontaneous adaptation behaviours through KAP scores using structured questionnaires. Chi-square tests, correlation matrix and Linear Multiple regression models were employed to analyze the data. Results: 15.4% of the subjects suffered from HRIs, and 68.2% never received health education about HRIs. The mean for knowledge (K-score) was 13.5 (SD = 6.008) for attitudes (A-score) 4.21 (SD = 2.167) for practices (P-score) 4.23 (SD = 1.988). There were noticeable differences in KAP-score with respect to educational level (P < 0.05), income level (P < 0.05) and work relevant experience (P < 0.05). Eventually, higher educational achievements, higher income status and relevant years of work experience were positive predictors for higher risk perception. Conclusion: There is a large room for improving health risk perception and adaptation capacity to heat waves among the brickfield workers. It will be very important to develop health educational programmes and enrich systematic educational resources to raise awareness.

The Occupational Health Nurse's Role in Protecting Workers From Heat-Related Illness.

The Occupational Health Nurse's Role in Protecting Workers From Heat-Related Illness.

Social interactions and heat stress mitigation among elderly people in a healthy city

BackgroundIncreased frequencies and duration of extreme heat events have caused severe heat stress, especially among elderly people. Despite its obvious cause and universally known preventive measures, heat stress preventive measures have not been implemented effectively at community levels. This study examined heat coping practices among elderly people and their associations with living conditions, social interactions, and community involvement. MethodsA self-administered questionnaire was done to assess heat-coping practices to mitigate heat stress, living conditions, and interactions with family, friends, and neighbours. Participants were 3000 randomly selected elderly people aged 65 years and older living in Owariasahi, Japan, a city that applies the 2004 Healthy City Approach. A generalised linear regression model was applied with binominal distribution to examine the association between social interactions and application of heat-coping practices. Sex and ages were adjusted in the model. FindingsAmong the 2127 elderly people who completed the survey, 745 (35·0%) had heat stress during the summer of the survey year. The presence of heat stress was higher in male participants living alone and having less interaction with friends and neighbours; only interaction with friends and relatives showed difference in the occurrence of the heat-related illness in female participants. The use of ice packs, air conditioners, and the opening of windows or doors were associated with the presence of heat stress. The odds of not applying relevant preventive practices were higher in participants disconnected from relatives and friends (odds ratio 1·52 [95% CI 1·12–2·04]). Participants living alone and disconnected from their neighbours showed similar trends to the connection with relatives and friends but not significantly. InterpretationThe findings of the study indicated that heat stress mitigative measures were underused in elderly people who are socially disconnected. Heat illness prevention programmes need to focus on outreach to the disadvantaged population. FundingJapan Society for the Promotion of Science.

Ice Sheet Cooling in the Field Reduces Morbidity in Exertional Heat Stroke.

Ice Sheet Cooling in the Field Reduces Morbidity in Exertional Heat Stroke.

Self-reported exertional heat illness and risk factors among collegiate marching band artists

Marching band (MB) artists are often part of the general student population and not required to complete a pre-participation health screening to identify predisposing medical conditions or risks for injury/illness. Anecdotally, exertional heat illnesses (EHI) are a concern for MB artists. As more athletic trainers provide MB healthcare, research is needed on EHI occurrence and MB associated EHI risk factors. We utilized an exploratory cross-sectional study design to determine EHI risk factors, including previous EHI occurrence, among collegiate MB artists. MB artists (n ​= ​1 207; age ​= ​[19.6 ​± ​1.3] years) actively participating in their college/university's MB during the 2019 football season completed an online survey to characterize demographics, medical history, medication and supplement use, and nutrition behaviors. Chi-square and binomial logistical regressions assessed associations between categorical variables. Previous EHI was reported by 50.6% of MB artists, with 466 (76.3%) experiencing exertional heat exhaustion and 31 (5.1%) exertional heat stroke. More females reported exertional heat exhaustion overall (68.2%, p ​< ​0.001) and in the previous year (73.3%, p ​< ​0.001). Experiencing a previous EHI was significantly associated with having a mood/neurological condition (63.5%, p ​< ​0.001), diagnosed (74.3%, p ​= ​0.004) or perceived eating disorder (66.7%, p ​< ​0.001), and taking prescription medications (59.4%, p ​< ​0.001), over-the-counter medications (58.9%, p ​= ​0.002), and supplements (55.4%, p ​= ​0.037). Half of collegiate MB artists reported experiencing previous EHIs and engaged in behaviors known to increase EHI risk. MB artists should complete pre-participation examinations to identify pre-existing medical conditions and risks for adverse medical events. Healthcare providers working with MB artists should develop policies and procedures to mitigate EHI risks and occurrence.

Inhibition of personal protective action against heat by gender stereotypes: A Japanese survey conducted in the summer of 2023

Exposure to extreme heat significantly affects human health and often causes death. Public health agencies encourage people to take preventive action against heat illness. Research on risk reduction behavior reveals that perceived effectiveness, self-efficacy, and risk perception motivate people to implement measures against various risks. This study empirically examines how gender stereotyping affects the use of umbrellas. Accordingly, Tokyo residents (N = 658) were surveyed on September 27 and 28, 2023, regarding their frequency of use of protective materials against heat during the summer of 2023. Results revealed that the survey participants associated the use of umbrellas more with women than with men. Hence, gender stereotype reduced the participants' use of umbrellas regardless of their gender. Self-efficacy had a stronger effect on umbrella use than any other explanatory variable. This study did not find evidence that perceived effectiveness, cost, and effort determine umbrella use. The findings imply that while creating messages to promote the adoption of preventive measures against extreme heat, they should consider how stereotypes affect people's willingness to adopt certain measures.

Sex differences in thermophysiological responses of elderly to low-intensity exercise during uncompensable heat strain

PurposeThe rising frequency of extreme heat events poses an escalating threat of heat-related illnesses and fatalities, placing an additional strain on global healthcare systems. Whether the risk of heat-related issues is sex specific, particularly among the elderly, remains uncertain.Methods16 men and 15 women of similar age (69 ± 5 years) were exposed to an air temperature of 39.1 ± 0.3 °C and a relative humidity (RH) of 25.1 ± 1.9%, during 20 min of seated rest and at least 40 min of low-intensity (10 W) cycling exercise. RH was gradually increased by 2% every 5 min starting at minute 30. We measured sweat rate, heart rate, thermal sensation, and the rise in gastrointestinal temperature (Tgi) and skin temperature (Tsk).ResultsTgi consistently increased from minute 30 to 60, with no significant difference between females and males (0.012 ± 0.004 °C/min vs. 0.011 ± 0.005 °C/min; p = 0.64). Similarly, Tsk increase did not differ between females and males (0.044 ± 0.007 °C/min vs. 0.038 ± 0.011 °C/min; p = 0.07). Females exhibited lower sweat rates than males (0.29 ± 0.06 vs. 0.45 ± 0.14 mg/m2/min; p < 0.001) in particular at relative humidities exceeding 30%. No sex differences in heart rate and thermal sensation were observed.ConclusionElderly females exhibit significantly lower sweat rates than their male counterparts during low-intensity exercise at ambient temperatures of 39 °C when humidity exceeds 30%. However, both elderly males and females demonstrate a comparable rise in core temperature, skin temperature, and mean body temperature, indicating similar health-related risks associated with heat exposure.

Heat vulnerability and spatial equity of cooling center: Planning implications from the Korean case

Over the past decade, the number of patients with heat-related illnesses has steeply increased in South Korea. South Korea's main heat adaptation planning revolves around providing cooling shelters, mostly in the form of elderly centers, to those who cannot afford adequate cooling resources. While implementing such a policy is important, it is also important to evaluate the effectiveness of existing policies to derive useful planning implications for future heat adaptation planning. Controlling for the spatial autocorrelation of residuals using the Generalized Least Squares (GLS), we found that the cooling centers in Seoul are overall well-distributed which was attributable to the local heat response policies. However, cooling shelters have been mostly designated in senior shelters lacking mainstreamed discussion that heat vulnerability can be influenced by much diverse factors than age.

Wearable and ingestible technology to evaluate and prevent exertional heat illness: A narrative review.

Exertional heat illness remains a constant threat to the athlete, military service member, and laborer. Recent increases in the number and intensity of environmental heat waves places these populations at an ever increasing risk and can be deadly if not recognized and treated rapidly. For this reason, it is extremely important for medical providers to guide athletes, service members, and laborers in the implementation of awareness, education, and measures to reduce or mitigate the risk of exertional heat illness. Within the past 2 decades, a variety of wearable technology options have become commercially available to track an estimation of core temperature, yet questions continue to emerge as to its use, effectiveness, and practicality in athletics, the military, and the workforce. There is a paucity of data on the accuracy of many of these newer devices in the setting of true heat stroke physiology, and it is important to avoid overreliance on new wearable technology. Further research and improvement of this technology are critical to identify accuracy in the diagnosis and prevention of EHI.

Experimental and numerical investigation of thermal environment of the child trapped in a parked vehicle

Pediatric vehicular hyperthermia (PVH) has aroused wide public concern recently. High temperatures in closed vehicles with full sun exposure and no ventilation in summer seriously endanger children's lives. Aiming at this practical problem, this study first took the temperature of child’s core body as a standard, and divided the hyperthermia into three stages: un-compensable heating (Tc > 37ºC), heat stroke (Tc > 40ºC) and critical thermal maximum (Tc > 42ºC). On this basis, two weeks of outdoor parking experiments during 10:00–18:00, using an equivalent size dummy were conducted to explore the influence of ambient temperature and solar irradiation on cabin temperature, humidity, and child’s core body temperature. According to the experimental results, at an ambient temperature of 32.4ºC, the child in the cabin developed un-compensable heating within 72 min, suffered heat stroke within 129 min, and reached the critical thermal maximum within 151 min. Considering the limitations of the experiment, a numerical study was conducted to analyze the effects of ambient temperature, solar irradiation, and window radiation characteristics on cabin temperature and flow fields comprehensively. Simulation results were in good agreement with the experiments: even at low ambient temperature Ta = 23ºC or weak solar irradiation (ts = 18:00) condition, the temperature in a closed compartment could reach the "hazardous" level. This study can provide guidance for public to increase security and prevention awareness, and promote the development of relevant policies and technologies.

Association of malignant hyperthermia and exertional heat illness in young athletes: An analysis of awareness among clinical and athletic first responders.

Malignant hyperthermia (MH), a rare inherited condition seen almost exclusively in the perioperative setting, is triggered by volatile anesthetics or an intravenous paralytic drug, succinylcholine. It can, however, occur without any exposure to anesthetic drugs, being associated with heat illness and rhabdomyolysis, thus presenting a little-known risk to young athletes exercising in hot environments. This study aimed to determine the first responder awareness of MH and its association with heat illness in young athletes within athletic and clinical environments. Awareness within the clinical milieu was assessed by an institutional chart review of 3296 charts. The identified heat illness cases were examined for treatment consistent with the management of a suspected episode of MH. Awareness among first responders in an athletic setting was examined by a survey administered to a total of 1,500 coaches and athletic trainers at the high school level along with emergency medical services providers across the United States. No treatment consistent with the suspicion of MH was noted among clinical first responders, suggesting a lack of awareness. Survey administration also revealed a limited amount of knowledge of MH and its potential role in heat illness. The results point to lack of awareness among pre-hospital and hospital-based first responders of the relationship between MH and heat illness in young athletes. An effort to educate these members of the healthcare community can contribute to an expeditious and life-saving intervention. First responders who may interact with a young athlete have low knowledge of MH and its relationship to heat illness. Similar lack of awareness exists among hospital personnel who care for young individuals with heat illness. Educating the first responders about this condition can speed up the time to intervene and save lives.

Post-exercise management of exertional hyperthermia in dogs participating in dog sport (canicross) events in the UK

Exercise is a common trigger of heat-related illness (HRI) events in dogs, accounting for 74% of canine HRI cases treated under primary veterinary care in the United Kingdom. However, few empirical studies have evaluated the effectiveness of differing cooling methods for dogs with exertional hyperthermia or HRI. This study aimed to prospectively evaluate effects of ambient conditions and post-exercise management practices (cooling methods and vehicular confinement) on the post-exercise temperature change of dogs participating in UK canicross events. Canine temperature was recorded at three intervals post-exercise: as close as possible to 0- (immediately post-exercise), 5-, and 15-min post-exercise. Ambient conditions and post-exercise management were recorded for 115 cooling profiles from 52 dogs. In 28/115 (24.4%) profiles, the dog's temperature increased during the first 5-min post-exercise. Overall, 68/115 (59.1%) profiles included passive cooling (stood or walked outside), 35 (30.4%) active cooling (cold-water immersion or application of a cooling coat), and 12 (10.4%) involved no cooling and were immediately housed in vehicles. No dogs developed hypothermia during the study and no adverse effects were observed from any cooling method. In hyperthermic dogs, overall post-exercise body temperature change was significantly negatively associated (i.e. the dogs cooled more) with 0-min post-exercise body temperature (β = −0.93, p < 0.001), and not being housed in a vehicle (β = −0.43, p = 0.013). This study provides evidence cold-water immersion (in water at 0.1–15.0 °C) can be used to effectively and safely cool dogs with exertional hyperthermia. Progressive temperature increases in many dogs - even after exercise has terminated - supports the message to “cool first, transport second” when managing dogs with HRI. When transporting dogs post-exercise or with HRI even after active cooling, care should be taken to cool the vehicle before entry and promote air movement around the dog during transport to facilitate ongoing cooling and prevent worsening of hyperthermia during travel.

Effects of adaptation measures to extreme heat throughout medium and high temperature periods, case study at the Osaka expo site

For the Osaka-Kansai Expo, to be held from April to October 2025, it is necessary to manage the exhibition site with consideration for countermeasures against heat in order to make safe and active use of the outdoor space. In this study, we compared meteorological data observed at Expo site on the sea coast, and at the Osaka Meteorological Observatory in the city center to analyze the quantitative relationship between meteorological elements at both locations, calculated thermal environment indices using these meteorological data, and considered the effects of implementing adaptation measures against the heat. The effect of solar radiation shading is predominant in lowering SET* and WBGT. During the medium temperature period, before mid-June and after mid-September, solar radiation shading avoids uncomfortable conditions, and during the high temperature period, from late June to mid-July and mid-August to early September, solar radiation shading, surface cover improvement, and mist spraying reduce the risk of heat stroke. However, during the extremely hot period, from late July to early August, the risk of heat stroke cannot be avoided by any of the adaptation measures to heat.

"Breaking down in tears, soaked in sweat, and sick from the heat": Media-based composite narratives of first responders working during the 2021 Heat Dome.

During the summer of 2021, a deadly, unprecedented multiday Heat Dome engulfed western Canada. As a result of this extreme heat event (EHE), emergency dispatchers received an unparalleled increase in incoming 911 calls for ambulance, police, and fire (as first responders) services to attend to hundreds of heat-vulnerable community members succumbing to the heat. With 103 all-time heat records broken during this EHE and indoor temperatures of nearly 40°C, the first responders attending these calls faced extensive job demands and highly challenging operating conditions. Initial investigations have explored the health system-level impacts; however, little has been done to explore the impact on the first responders themselves. Therefore, this study aimed to improve our understanding of EHEs' impacts on the operational capabilities and health of first responders, specifically police, fire, ambulance, and dispatch services. A systematized review and content analysis of media articles published on the 2021 Heat Dome in Canada was conducted (n = 2909), and four media-based composite narratives were developed highlighting police, fire, ambulance, and dispatch services. The Job Demands-Resources (JD-R) model was applied as atheoretical framework for occupational burnout. The media-based composite narratives highlighted that first responders faced record-breaking call volumes, increased mental-health-related claims, and exhaustive heat-related physiological stress. Using the JD-R model as a theoretical framework for occupational burnout, we identified three measures of stressful job demand: work overload (e.g., the surge in call volume, firefighters responding to medical emergencies), emotional demands (e.g., severe medical emergencies, sudden deaths, unresponsive patients, distraught family members), and physical demands (e.g., resuscitation in personal protective equipment, heat-related illness). The experiences described underscore the importance of supporting first responders during work in extreme heat conditions. These findings have important implications for addressing rising rates of burnout during and following public health crises, such as EHEs, a problem that is increasingly being recognized as a threat to the Canadian public healthcare system.

Escalating climate-related health risks for Hajj pilgrims to Mecca.

Global temperatures are on the rise, leading to more frequent and severe heatwaves with associated health risks. Heat-related illnesses (HRIs) are an increasing threat for travellers to hot climate destinations. This study was designed to elucidate the interplay between increasing ambient temperatures, incidence of HRIs and the effectiveness of mitigation strategies during the annual Hajj mass gathering over a 40-year period. An observational study was conducted utilizing historical records spanning four decades of meteorological data, and the rates of heat stroke (HS) and heat exhaustion (HE) during the Hajj pilgrimage in Mecca, Saudi Arabia. With an annual population exceeding 2million participants from over 180 countries, the study analysed temporal variations in weather conditions over two distinct Hajj hot cycles and correlated it with the occurrence of HS and HE. The effectiveness of deployed mitigation measures in alleviating health vulnerabilities between the two cycles was also assessed. Throughout the study period, average dry and wet bulb temperatures in Mecca escalated by 0.4°C (Mann-Kendall P < 0.0001) and 0.2°C (Mann-Kendall P = 0.25) per decade, respectively. Both temperatures were strongly correlated with the incidence of HS and HE (P < 0.001). Despite the intensifying heat, the mitigation strategies including individual, structural and community measures were associated with a substantial 74.6% reduction in HS cases and a 47.6% decrease in case fatality rate. The study underscores the escalating climate-related health risks in Mecca over the study period. The mitigation measures' efficacy in such a globally representative setting emphasizes the findings' generalizability and the importance of refining public health interventions in the face of rising temperatures.

Heat Stroke Induces Pyroptosis in Spermatogonia via the cGAS-STING Signaling Pathway.

To explore the mechanism whereby cGAS-STING pathway regulates the pyroptosis of cryptorchidism cells, with a view to finding a new strategy for clinically treating cryptorchidism-induced infertility. Spermatogonial GC-1 cells were heat stimulated to simulate the heat hurt microenvironment of cryptorchidism. The cell viability was assayed by CCK-8, and cellular DNA damage was detected by gamma-H2AX immunofluo-rescence assay. Flow cytometry was employed to assess pyroptosis index, while western blot, ELISA and PCR were used to examine the expressions of pyroptosis-related proteins (Caspase-1, IL-1beta, NLRP3) and cGAS-STING pathway proteins (cGAS, STING). After STING silencing by siRNA, the expressions of pyroptosis-related proteins were determined. Pyroptosis occurred after heat stimulation of cells. Morphological detection found cell swelling and karyopyknosis. According to the gamma-H2AX immunofluorescence (IFA) assay, the endonuclear green fluorescence was significantly enhanced, the gamma-H2AX content markedly increased, and the endonuclear DNA was damaged. Flow cytometry revealed a significant increase in pyroptosis index. Western blot and PCR assays showed that the expressions of intracellular pyrogenic proteins like Caspase-1, NLRP3 and GSDMD were elevated. The increased STING protein and gene expressions in cGAS-STING pathway suggested that the pathway was intracellularly activated. Silencing STING protein in cGAS-STING pathway led to significantly inhibited pyroptosis. These results indicate that cGAS-STING pathway plays an important role in heat stress-induced pyroptosis of spermatogonial cells. After heat stimulation of spermatogonial GC-1 cells, pyroptosis was induced and cGAS-STING pathway was activated. This study can further enrich and improve the molecular mechanism of cryptorchidism.

Heat exposure as a cause of injury and illness in mine industry workers.

The objective of this study was to explore the association between ambient temperature and injuries and illnesses experienced by mine industry workers. Eleven years of de-identified data from a mine industry company in Australia was explored in regards to injuries and illnesses occurring due to outdoor exposure. Each case was filtered for reported symptoms, and meteorological data to match the location of the mine site and date reported were sourced. Of the 18 931 injuries and illnesses observed over the 11-year period, 151 cases of heat-related illness due to outdoor exposure were reported. Twenty-five conditions/symptoms of heat-illness were found, with the most prevalent being dehydration (n = 81), followed by heat rash (n = 40), dizziness (n = 24), and headache (n = 23). The mean number of symptoms reported by each worker was 2 ± 1. There was a positive correlation between ambient temperature and injuries/illnesses (r2 = 0.89, P < 0.001), where, as temperature increased so did the number of reported heat-related illnesses. Underreporting of heat-related illness and injury in the mining industry is likely, which is a risk to the health and wellbeing of employees. Workers require industry specific training about the severity of heat stress and the associated prevention strategies.

From Homer to the present: an account of historical perspectives of heat illness

Heat illness has been known and written about for thousands of years. Over time, there has been improvement and refinement in its diagnosis and treatments. This article discusses what was known and written about heat illness over the centuries. It sees how treatments have been in and out of fashion, and how our understanding has developed and been refined over the years, albeit with some detours.

Effect of hyperbaric oxygen treatment on patients with heatstroke complicated by multiple organ dysfunction:A retrospective study

BackgroundThe benefits of hyperbaric oxygen (HBO) in treating animals with heat stroke (HS) have been established. This study aims to retrospectively analyze the effect of HBO on multiple organ dysfunction following HS in humans. MethodsRetrospective data were collected from patients with HS admitted to our hospital in the past 7 years. Patients were categorized into groups based on whether they received HBO therapy. The study compared various factors, including sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation-Ⅱ (APACHE-Ⅱ) scores, mortality rates, neurological function scores, serum myocardial enzyme levels, liver, kidney, and coagulation function indicators, blood routine results, electrolyte levels, and modified Barthel index (MBI) score for standard daily living ability before treatment and after 2 and 4 weeks of treatment. ResultsThe mortality rates in the HBO and control group were 0% and 8.49%, respectively. Upon admission, the HBO group had higher SOFA and APACHE-Ⅱ scores and lower neurological, coagulation, and liver functions than those of the control group. HBO treatment significantly improved SOFA, APACHE-Ⅱ, and neurological scores while relieving levels of alanine aminotransferase, aspartate aminotransferase, creatinine, and myocardial enzymes. Additionally, it mitigating lymphocyte and platelet count decline caused by HS. The MBI score was significantly enhanced after treatment in the HBO group. ConclusionsClinical practice advocates administering HBO therapy to patients with severe illness, organ damage, and nerve impairment. Compared with conventional treatment, combined HBO therapy demonstrated superior efficacy in alleviating multiple organ dysfunction and improving daily living ability in patients with HS.