Occurrence Of Heat Stroke Research Articles

Machine learning-based analysis and prediction of meteorological factors and urban heatstroke diseases.

Heatstroke is a serious clinical condition caused by exposure to high temperature and high humidity environment, which leads to a rapid increase of the core temperature of the body to more than 40°C, accompanied by skin burning, consciousness disorders and other organ system damage. This study aims to analyze the effect of meteorological factors on the incidence of heatstroke using machine learning, and to construct a heatstroke forecasting model to provide reference for heatstroke prevention. The data of heatstroke incidence and meteorological factors in a city in South China from May to September 2014-2019 were analyzed in this study. The lagged effect of meteorological factors on heatstroke incidence was analyzed based on the distributed lag non-linear model, and the prediction model was constructed by using regression decision tree, random forest, gradient boosting trees, linear SVRs, LSTMs, and ARIMA algorithm. The cumulative lagged effect found that heat index, dew-point temperature, daily maximum temperature and relative humidity had the greatest influence on heatstroke. When the heat index, dew-point temperature, and daily maximum temperature exceeded certain thresholds, the risk of heatstroke was significantly increased on the same day and within the following 5 days. The lagged effect of relative humidity on the occurrence of heatstroke was different with the change of relative humidity, and both excessively high and low environmental humidity levels exhibited a longer lagged effect on the occurrence of heatstroke. With regard to the prediction model, random forest model had the best performance of 5.28 on RMSE and dropped to 3.77 after being adjusted. The incidence of heatstroke in this city is significantly correlated with heat index, heatwave, dew-point temperature, air temperature and zhongfu, among which the heat index and dew-point temperature have a significant lagged effect on heatstroke incidence. Relevant departments need to closely monitor the data of the correlated factors, and adopt heat prevention measures before the temperature peaks, calling on citizens to reduce outdoor activities.

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.

Wearable Heat Stroke Detection System in IoT-based Environment

Increase in global temperature recently has led to heat stroke which can greatly harm the human body. This paper studies the development of a wearable IoT-based heat stroke detection device. This device measured heartbeat rate, surrounding temperature, relative humidity and core body temperature by using several sensors. It generated heat stroke risk level via Fuzzy controller and an alert module alerted the user. The IoT part of this invention has included ThingSpeak server and an android application to store, visualize and display physiological data numerically and graphically. There was 5-phase performance test carried out and the phases of the test were standing, walking, running, walking and standing to evaluate device performance. The results showed that thermal heat stroke risk coefficient (THSRC) was the main factor in the detection of potential heat stroke followed by the other two factors which were core body temperature and heartbeat rate. Based on the results, it is concluded that this device is capable to detect potential heat stroke and alert the user early before any occurrence of heat stroke. It can be inferred that the potential heat stroke will only be detected when the heat stroke risk level is above 25 under the conditions of THSRC of above 37.5, core body temperature of above 38.5 degree Celsius and heartbeat rate of above 135 beats per minute. As an advantage, this wearable IoT-based heat stroke detection device enables user to carry out any activity in hot environment without any worries of being stricken with the heat stroke as the device will immediately alert the user first whenever there is potential heat stroke detected.

Sympathetic and cardiovagal baroreflex sensitivity as related to heat stroke

Heat stroke diagnosis takes place when core temperature exceeds 40.5°C. Many risk factors, environmental and non-environmental, are associated with increased occurrence of heat stroke. Early diagnosis of a heat related illness is believed to be important in the effective reduction of heat stress mortality and morbidity rates. Sympathetic and cardiovagal baroreflex sensitivity could provide metrics to aid in the early diagnosis. Data analysis took place using previous data from an experiment where 24 subjects performed 30 minutes of cardiovascular exercise in a chamber with WBGT equal to 27.5°C. The primary experimental objective was observation of a relationship between transepidermal water loss and cardiovascular metrics. Thus, the design of experiments limited the amount of valuable information able to be extracted pertaining to sympathetic and cardiovagal baroreflex sensitivity. However, a test of means demonstrated that diastolic pressure and heart rate underwent significant changes with time in the hot and humid environment.

Effect of glucocorticoid depletion on heat-induced Hsp70, IL-1β and TNF-α gene expression

When exposed to heat, conscious naive rats may develop lethal heatstroke, depending on heat load, i.e., time spent at high body core temperature. The occurrence of heatstroke was hypothesized to result from a defective glucocorticoid secretion related to altered heat-stress responses. We thus investigated the potential involvement of glucocorticoids in heat tolerance and its consequences on physiological responses, heat shock protein 70 (Hsp70), and cytokine mRNA expressions. Two hours before heat exposure, the animals were injected either with metyrapone, an inhibitor of corticosterone synthesis, or with its vehicle. Heat exposure lasted for 15, 30, 45 or 60 min. Thereafter, the rats were distributed into three groups according to their heat load: null, moderate (without any lethal risk) and intense (with lethal risk). Physiological responses were evaluated with colonic temperature, plasma lactate and hematocrit. Brain responses were assessed in frontal cortex through Hsp70, interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) mRNA expressions. The animals with a severe heat load exhibited a high hematocrit, increased plasma lactate level and enhanced brain IL-1β and Hsp70 mRNA expressions. Independent of the heat load, Metyrapone rats showed the same thermophysiological responses and IL-1β and Hsp70 mRNA expressions when compared with vehicle rats. However, the Metyrapone rats experiencing an intense heat load exhibited an increased TNF-α mRNA expression. In conclusion, these data (i) confirm that heat load is important in the calibration of the risk attached to heat exposure; and (ii) suggest that corticosterone synthesis inhibition may favor TNF-α mRNA expression without any effect on Hsp70 mRNA expression.

Mortality of patients with heatstroke admitted to intensive care units during the 2003 heat wave in France: A national multiple-center risk-factor study*

Heatstroke requires active body cooling and organ failure supportive care. Although heat waves are expected to recur over the next decades, little is known about the risk factors for mortality in heatstroke patients. We examined the prognosis and risk factors for hospital mortality in patients with heatstroke admitted to an intensive care unit (ICU) during the heat wave in France in August 2003. A questionnaire was sent to the physicians leading an ICU in France to identify the patients admitted with heatstroke during August 2003. Data included demographics, factors predisposing to heatstroke, severity during the first day in the ICU, air conditioning in the ICU, and hospital mortality. Risk factors for mortality were determined in multivariate Cox proportional hazards analysis. None. Data were obtained for 345 patients. Hospital mortality was 62.6%. Occurrence of heatstroke at home or in a healthcare facility rather than in a public location, high Simplified Acute Physiology Score II, high body temperature, prolonged prothrombin time, use of vasoactive drugs within the first day in the ICU, and patient management in an ICU without air conditioning were independently associated with an increased risk of death. Mortality of patients admitted to the ICU with heatstroke is high. Predictors of mortality are available within the first 24 hrs after admission. Furthermore, in this study, air conditioning in the ICU was associated with improved outcome.

Inhibition of different types of nitric oxide synthase: effect on thermoregulation in the rat exposed to high ambient temperature

Vascular and immunological mechanisms are both likely to be involved in heatstroke, this condition being preceded by a decrease in cerebral blood flow and an increase in brain cytokine concentrations. As the two mechanisms involve a nitridergic step, we analysed their respective role in heat tolerance by exposing vigil rats to heat after treatment with nitric oxide synthases (NOS) antagonists: non-specific inhibitors N ω-nitro- l-arginine (LNA) and N-nitro- l-arginine-methyl-ester (L-NAME); 7-nitroindazol (neuronal NOS inhibitor) and aminoguanidine (AG) (inducible NOS inhibitor). Heat exposure was interrupted when clinical signs occurred or when colonic temperature reached 43°C. LNA and L-NAME dramatically reduced heat tolerance, while AG did not modify it. These results suggest the involvement of constitutive NOS in heat tolerance. Inducible NOS does not seem to be involved in the occurrence of heatstroke.