Average Wet Bulb Globe Temperature Research Articles

Changes in wet bulb globe temperature and risk to heat-related hazards in Bangladesh

The rise in temperatures and changes in other meteorological variables have exposed millions of people to health risks in Bangladesh, a densely populated, hot, and humid country. To better assess the threats climate change poses to human health, the wet bulb globe temperature (WBGT) is an important indicator of human heat stress. This study utilized high-resolution reanalysis data from the fifth-generation European Centre for Medium-Range Weather Forecasts (ECMWF ERA5) to analyze the spatiotemporal changes in outdoor WBGT across Bangladesh from 1979 to 2021, employing Liljegren's model. The study revealed an increase in the annual average WBGT by 0.08–0.5 °C per decade throughout the country, with a more pronounced rise in the southeast and northeast regions. Additionally, the number of days with WBGT levels associated with high and extreme risks of heat-related illnesses has shown an upward trend. Specifically, during the monsoon period (June to September), there has been an increase of 2–4 days per decade, and during the pre-monsoon period (March to May), an increase of 1–3 days per decade from 1979 to 2021. Furthermore, the results indicated that the escalation in WBGT has led to a five-fold increase in affected areas and a three-fold increase in days of high and extreme heat stress during the monsoon season in recent years compared to the earlier period. Trend and relative importance analyses of various meteorological variables demonstrated that air temperature is the primary driver behind Bangladesh's rising WBGT and related health risks, followed by specific humidity, wind speed, and solar radiation.

Research on the Effect of Spray Ventilation Cooling Systems on Human Physiological and Psychological Indexes

Hot working environment not only affects work efficiency, but also poses a potential threat to the physical and mental health of staff. The current common method for dealing with high temperatures is spray-only or ventilation-only. To investigate the impact of different spray and ventilation modes on indoor high-temperature environments, this study examined their effects on indoor environmental parameters, average skin temperature, and psychological indicators. By establishing an experimental platform for high-temperature thermal environments, a spray ventilation cooling system was implemented, and its cooling efficacy in the indoor thermal environment was analyzed. The environmental classification of the high-temperature working environment under experimental conditions is provided based on the experimental data. A comparison and analysis of environmental parameters and physiological and psychological indicators between moderate and high-temperature environments were conducted. The combination of spray and ventilation modes resulted in a 5.3 °C reduction in air temperature, a 24.1% increase in average relative humidity, and a 3.3 °C reduction in average Wet-bulb Globe Temperature (WBGT). The cooling effect was increased by 2.3 °C and the average relative humidity was increased by 10.8% compared to spray-only and ventilation-only modes. In spray and ventilation mode, when the spray volume is increased by 15 mL/min, the air temperature is reduced by 8.2 °C, the average relative humidity is increased by 31.9%, and the average WBGT is reduced by 5.1 °C. This study has guiding significance for finding a reasonable cooling scheme to cope with indoor high-temperature environments.

Pilot study: Occupational and public health consequences of elevated temperatures in restaurant kitchens

Restaurant kitchens are relatively warm and can be made even warmer when the outdoor temperature is excessive. Hot indoor conditions can lead to workers experiencing health effects such as heat stress as well as negatively impact food storage and food cooling. This study’s objective was to simultaneously identify potential occupational health and public health effects inside restaurant kitchens due to warm conditions. Wet Bulb Globe Temperature (WBGT) measurements were collected and the results were compared to the corresponding Threshold Limit Value and Action Limit. Internal temperatures of refrigerators and freezers were gathered and observations were made of any food being held inside the kitchen. Eight premises in the Greater Toronto Area were included in this study. Five of the sites had average WBGT values at or above the Action Limit, which is when heat stress management programs are recommended. Most sites had refrigerators operating over the required 4°C and three sites had freezers operating above the requisite −18°C. Food was observed to be held at temperatures that can promote bacterial growth in 50% of the sites. This study found that hot kitchen environments could result in both heat stress conditions as well as compromise cold food storage and food holding.

Work-rest regimens for work in hot environments: A scoping review.

To limit exposures to occupational heat stress, leading occupational health and safety organizations recommend work-rest regimens to prevent core temperature from exceeding 38°C or increasing by ≥1°C. This scoping review aims to map existing knowledge of the effects of work-rest regimens in hot environments and to propose recommendations for future research based on identified gaps. We performed a search of 10 databases to retrieve studies focused on work-rest regimens under hot conditions. Forty-nine articles were included, of which 35 were experimental studies. Most studies were conducted in laboratory settings, in North America (71%), on healthy young adults, with 94% of the 642 participants being males. Most studies (66%) employed a protocol duration ≤240 min (222 ± 162 min, range: 37-660) and the time-weighted average wet-bulb globe temperature was 27 ± 4°C (range: 18-34). The work-rest regimens implemented were those proposed by theAmerican Conference of Governmental and Industrial Hygiene (20%),National Institute of Occupational Safety and Health (11%), or the Australian Army (3%). The remaining studies (66%) did not mention how the work-rest regimens were derived. Most studies (89%) focused on physical tasks only. Most studies (94%) reported core temperature, whereas only 22% reported physical and/or mental performance outcomes, respectively. Of the 35 experimental studies included, 77% indicated that core temperature exceeded 38°C. Although work-rest regimens are widely used, few studies have investigated their physiological effectiveness. These studies were mainly short in duration, involved mostly healthy young males, and rarely considered the effect of work-rest regimens beyond heat strain during physical exertion.

Urban Versus Lake Impacts on Heat Stress and Its Disparities in a Shoreline City.

Shoreline cities are influenced by both urban-scale processes and land-water interactions, with consequences on heat exposure and its disparities. Heat exposure studies over these cities have focused on air and skin temperature, even though moisture advection from water bodies can also modulate heat stress. Here, using an ensemble of model simulations covering Chicago, we find that Lake Michigan strongly reduces heat exposure (2.75°C reduction in maximum average air temperature in Chicago) and heat stress (maximum average wet bulb globe temperature reduced by 0.86°C) during the day, while urbanization enhances them at night (2.75 and 1.57°C increases in minimum average air and wet bulb globe temperature, respectively). We also demonstrate that urban and lake impacts on temperature (particularly skin temperature), including their extremes, and lake-to-land gradients, are stronger than the corresponding impacts on heat stress, partly due to humidity-related feedback. Likewise, environmental disparities across community areas in Chicago seen for skin temperature are much higher (1.29°C increase for maximum average values per $10,000 higher median income per capita) than disparities in air temperature (0.50°C increase) and wet bulb globe temperature (0.23°C increase). The results call for consistent use of physiologically relevant heat exposure metrics to accurately capture the public health implications of urbanization.

Variations of wet-bulb globe temperature across high school athletics in South Carolina.

The purpose was to describe wet bulb globe temperature (WBGT) throughout a high school fall athletic season (August to November) after a state-wide mandate requiring schools to use a WBGT-guided activity modification table with categories (AMTC). A cross-sectional research design utilized 30 South Carolina high schools. The independent variables were region (upstate, midlands, and coastal), sport (football, tennis, cross-country), month, start times (7-10 am, 10 am-3pm, 3-6pm, and 6-9pm), and event type (practice, competition). Dependent variables were event frequency, average WBGT, and AMTC. Practice WBGT was 78.7 ± 8.2 °F (range: 34.7 to 99.0 °F). A significant difference for WBGT across month (F6, 904.7 = 385.07, P < 0.001) existed, with early September hotter than all other months (84.8 °F ± 3.8, P < 0.001). Every month had practices in each AMTC, until early November. Most events (64.6%, n = 1986) did not change AMTC; however, 9.1% (n = 281) changed to a hotter category. The 10 am-3pm start time was significantly hotter than all other time frames (83.0 °F ± 7.2, P < 0.05). Tennis experienced hotter practices (79.9 °F ± 6.9) than football (78.4 °F ± 8.5; P < 0.001) and cross country (78.2 °F ± 8.8, P < 0.001). Schools in the Midlands experienced hotter practices (80.1 °F ± 7.8) than upstate (P < 0.001) and coastal schools (P = 0.005). Competition WBGT was significantly cooler than practices (72.3 ± 10.5 °F, t = 12.04, P < 0.001) and differed across sports (F2, 20.78 = 18.39, P < .001). Both cross-country (P = 0.003) and tennis (P < 0.001) were hotter than football. Schools should continuously monitor WBGT throughout practices and until November to optimize AMTC use. Risk mitigation strategies are needed for sports other than football to decrease the risk of exertional heat illnesses.

Occurrence of Occupational Injuries and Within Day Changes in Wet Bulb Temperature Among Sugarcane Harvesters

ABSTRACT Objective Climate change has implications for human health worldwide, with workers in outdoor occupations in low- to middle-income countries shouldering the burden of increasing average temperatures and more frequent extreme heat days. An overlooked aspect of the human health impact is the relationship between heat exposure and increased risk of occupational injury. In this study, we examined the association between occupational injury occurrence and changes in outdoor temperatures through the workday among a cohort of Guatemalan sugarcane harvesters. Methods Occupational injuries recorded for the 2014/2015 to 2017/2018 harvest seasons were collected from a large agribusiness employing male sugarcane harvesters in Southwest Guatemala. Wet Bulb Globe Temperature (WBGT) for the same period was collected from the El Balsamo weather station. We used a logistic mixed effects model to examine the association between injury occurrence and (1) the average WBGT during the hour injury was recorded, (2) the average WBGT during the hour prior to the injury being recorded, and (3) the change in the hourly average WBGT prior to the injury being recorded. Results There were 155 injuries recorded during the study period. Injuries were recorded most often between 14:00 and 16:00 (n = 62, 40%) followed by 8:00 and 10:00 (n = 56, 36%). There were significant differences in the average hourly WBGT and the hour in which injuries were recorded (p-value <.001). There were no observable associations between average hourly WBGT (OR: 1.00, 95%CI: 0.94, 1.05; p-value: 0.87), lagged average hourly WBGT (OR: 1.01, 95%CI: 0.97, 1.05; p-value: 0.71), or change in average hourly WBGT (OR: 0.96, 95%CI: 0.89, 1.04; p-value: 0.35) and recorded occupational injury. Conclusions This is the first study that has examined how changes in WBGT throughout the day are related to occupational injury among agricultural workers. Although this study did not demonstrate an association, there is a need for future research to examine how various measurements of WBGT exposure are related to occupational injury in agricultural worker populations.

Launching criteria of ‘Heatstroke Alert’ in Japan according to regionality and age group

To reduce heatstroke cases, the Japanese government launched ‘Heatstroke Alert’ in 2020. In this initiative, an alert is issued when the daily maximum wet bulb globe temperature (WBGT) is expected to reach or exceed 33 °C. However, heatstroke incidents at a daily maximum of WBGT of 33 °C can vary by regions and by age groups. In this study, we analyzed the heatstroke incidence in all 47 prefectures of Japan at the daily maximum WBGT of 33 °C, considering age groups. In addition, considering variations in heatstroke incidence by prefectures and age groups, alternative ‘Heatstroke Alert’ criteria (AHAC) by each prefecture and age group were examined. We also analyzed the daily maximum WBGT at which heatstroke incidence starts to increase (the WBGT threshold), as this can be an additional metric to ‘Heatstroke Alert’ for the prevention of heatstroke. The results showed that the northern region (higher latitudes) of Japan has more patients with heatstroke per population, at a daily maximum WBGT of 33 °C, than the southern region (lower latitudes), by factors of approximately 3–5, considering each age group. The suggested AHAC among 47 prefectures were 29.8 [27.7–31.4] °C for 7–17 years, 32.4 [30.2–33.9] °C for 18–64 years, and 30.8 [28.5–33.2] °C for ≥ 65 years, respectively. The northern region exhibited a lower WBGT threshold (defined as the value at which heatstroke incidence is 0.1 persons per 105 people) than the southern region by approximately 3.5°C–5°C, considering each age group. The calculated average WBGT threshold among 47 prefectures was 23.2 [20.4–25.3] °C for 7–17 years, 26.3 [24.2–28.1] °C for 18–64 years, and 23.1 [20.2–25.6] °C for ≥ 65 years, respectively. These findings are expected to contribute to the reinforcement of ‘Heatstroke Alert’ and the use of WBGT information in a more preventive manner.

Feasibility Study of Using Nebulizer-Retrofitted UAVs at Construction Projects: The Case Study of Residential Jobsites in Utah

Increased heat stress and air pollution are two major causes of health issues and productivity loss in the construction industry. This will be exacerbated by global warming and an increased possibility of extreme weather conditions in the future. Previous studies revealed that each 1°C rise in temperature reduces construction workers’ productivity by up to 2%. Also, it is found that a 10 μg/m3 particulate matter sized 2.5 μm (PM2.5) fluctuation over 25 days lowers workers’ daily production by 1%. As an effective dust control and cooling strategy, water spraying is used by practitioners to mitigate the effect of air pollution and heat-related problems on construction workers. Considering low costs and high mobility, unmanned aerial vehicles (UAVs) could be considered as a potential alternative for ground-based, stationary water spraying systems. To this end, a case study approach is adopted in this project to investigate the feasibility of using nebulizer-retrofitted UAVs in controlling air pollution and reducing heat stress at construction job sites. The case study consists of two different residential job sites in the state of Utah: one in Salt Lake City and the other one in St. George. The main contribution of this study is to determine the effect of aerial water spraying on air temperature and pollution at job sites. The outcomes of this study show that the average wet bulb globe temperature (WBGT) decreases 1.7° during the flight phase compared to average values for preflight and postflight phases. The aerial water spraying technique yields better and more water-efficient results in decreasing temperature at job sites compared to the existing approaches, such as stationary fans. Moreover, the results of PM variations illustrate that the mean value of particulate change was significantly different between flight and preflight (p=0.005), and flight and postflight (p<0.001) modes. Future studies should include the deployment of multiple drones flying simultaneously at job sites to cover larger areas.

Hematological parameters in a population of male bakers exposed to high heat work environment.

The aim of this study was to determine the hematological changes associated with heat exposure in a population of bakers. Personal information was collected using a questionnaire, and a venous blood sample was drawn at the end of a work shift from the bakers and from a control group. The average wet-bulb globe temperature (WBGT) index was measured in the workplaces of both the bakers and the controls. This cross-sectional study involved 137 bakers working in 20 bakeries and 107 controls who were comparable in terms of likely confounding factors. Hemoglobin and platelet values were abnormal among the bakers and statistically significantly different to the control group (P = 0.026, and P = 0.016 respectively). The average WBGT index in the bakeries was 37.4°C, while the average WBGT in the workplaces of the controls was 25.5°C, (P<0.0001). The changes in the bakers' hematological parameters were found to be associated with exposure to high environmental heat at bakeries, as measured by the WBGT index. Preventive measures should be introduced to reduce the adverse effect of heat exposure among bakers and directed toward the worker-equipment-environment triad.

Physical demands and physiological strain of American football referees while officiating

ABSTRACT Objectives Certain occupations are associated with greater risk of triggering a sudden cardiac event because of high levels of physical exertion and extreme thermal environments in which they occur. The extent to which sports officials––particularly high school (HS) American football referees––experience these conditions is unknown. Forty-six male HS officials (72% White/Caucasian; age = 48 ± 12 years, body mass index = 31.7 ± 6.6 kg·m−2) were studied to quantify the physiological strain and physical demands of officiating. Methods Referee demographics (e.g., experience, habitual exercise), pre-game urine specific gravity (USG), thermal (peak core temperature [Tcore]) and cardiovascular (average heart rate [HR]) strain, kinematic activity (e.g., total distance, speed, mechanical intensity), and environmental conditions were measured during 10 regular season varsity HS football games (≈2.5 h each) in the Southeastern United States (average wet bulb globe temperature and relative humidity: 18.9 ± 6.0 °C and 78.2% ± 12.1%). Analyses included descriptive statistics, bivariate correlations, and linear regression. Results Referees covered 5.2 ± 1.2 km per game, eliciting average HR and peak Tcore of 71.5% ± 8.0% HRmax and 38.3 ± 0.5 °C, respectively; 38% began games dehydrated (USG = 1.026 ± 0.004). Multiple regression analyses revealed that obesity (β = 0.34), not participating in regular exercise (β = −0.36), and officiating at lower mechanical intensity (β = −0.33) predicted greater cardiovascular strain (all p ≤ 0.03). White/Caucasian race/ethnicity (β = 0.59), younger age (β = −0.46), and obesity (β = 0.28) predicted greater thermal strain (all p ≤ 0.01). Conclusion HS football referees experienced elevated levels of physiological strain while officiating, with individual factors modulating the magnitude of strain. Strategies aimed at reducing obesity, increasing exercise participation, and improving cardiovascular health should be emphasized to mitigate strain and prevent cardiac events.

Physiological and biochemical parameters among a population of bakers exposed to environmental heat.

The aim of this study was to determine the physiological and biochemical changes among bakers, induced by heat exposure at the workplace. Information was collected by means of a self-administered questionnaire. Vital signs were measured and recorded by a trained nurse before and after each work shift. A venous blood sample was drawn at the end of each work shift. The mean wet-bulb globe temperature (WBGT) index in the bakeries and offices was measured. This was a cross-sectional study involving 137 bakers working in 20 bakeries, and 107 control subjects comparable in terms of age, race, marital status, years of service, income, and cigarette smoking. There was a significant weight loss and increase in the respiratory rate, the heart rate, and oral body temperature among the bakers compared to the control group. Sodium levels were significantly lower, while blood urea nitrogen levels were significantly higher, among the bakers than in the control group. There were unfavorably hot working conditions in the bakeries: the WBGT index in the bakeries was 37.4°C while the average WBGT for the offices was 25.5°C. The changes in the physiological and biochemical parameters among the bakers were found to be associated with exposure to high environmental heat in the bakeries, as judged by the WBGT index. Preventive measures should be aimed at reducing the adverse effects of heat exposure among bakers and should be directed towards the man-machine-environment triad. Int J Occup Med Environ Health. 2022;35(3):265-72.

Assessing the monthly heat stress risk to society using thermal comfort indices in the hot semi-arid climate of India

Extreme weather conditions, especially heatwave, are a threat to society, affecting livability, wellbeing, and social interactions. The present study aims to assess the monthly heat stress in the outdoor environment from 2010 to 2019 in Sonepat's municipality, representing a hot semi-arid climate. The authors applied three heat stress indices, namely, Wet bulb globe temperature (WBGT), Physiological equivalent temperature (PET), and Universal thermal climate index (UTCI), to estimate the grade of heat stress. While calculations, the highest average WBGT was found in July (33.4 ± 0.77 °C), demonstrating July in the “Extreme heat stress” category. The highest mean PET was found in June (42.47 ± 2.34 °C), indicating June in the “Extreme heat stress” category. The highest mean UTCI was found in June (38.58 ± 1.82 °C), demonstrating “Very strong heat stress.” The dry bulb temperature was found to be the most dominant parameter among meteorological parameters promoting extreme heat stress. It was concluded that extreme heat stress was observed in the Pre-monsoon hot weather season and summer monsoon season (especially in June), making the population vulnerable to mortality and morbidity. The findings could provide valuable information to people from various disciplines like Climate scientists, landscape designers, architects, and all relevant stakeholders to develop a heatwave action plan against adverse heat stress.

Risk factors for not finishing an ultramarathon: 4-year study in 23,996 race starters, SAFER XXI.

Limited data support prerace medical screening to identify risk factors for not finishing an endurance running race. The aim of the study was to determine risk factors associated with not finishing an ultramarathon. A prospective, cross-sectional study of Two Oceans ultramarathon (56 km) race starters who completed a prerace medical screening questionnaire. Race day environmental conditions were recorded on race day. Univariate analyses of risk factors associated with the did-not-finish (DNF) included race day factors and prerace medical screening history. Risk factors for DNF amongst 23,996 starters during the 56 km race included older age and females (P<0.0001). After adjusting for age and sex, the following were significant univariate risk factors: fewer years of running (P<0.0001), less previous race experience (P<0.0001), less training/racing per week (P=0.0002), lower average weekly training distance (P=0.0016), slower race vs. training speed (P<0.0001), lack of allergies (P=0.0100) and average wet-bulb globe temperature (P<0.0001). Females, older age, training-related factors (less training/racing, average weekly training distance, race vs. training speed) and average wet-bulb temperature, were risk factors for not finishing an ultramarathon. The results may not only assist runners and coaches in race preparation, but also have clinical implications for the medical planning prior to races.

Wet Bulb Globe Temperature and Recorded Occupational Injury Rates among Sugarcane Harvesters in Southwest Guatemala.

As global temperatures continue to rise it is imperative to understand the adverse effects this will pose to workers laboring outdoors. The purpose of this study was to investigate the relationship between increases in wet bulb globe temperature (WBGT) and risk of occupational injury or dehydration among agricultural workers. We used data collected by an agribusiness in Southwest Guatemala over the course of four harvest seasons and Poisson generalized linear modelling for this analysis. Our analyses suggest a 3% increase in recorded injury risk with each degree increase in daily average WBGT above 30 °C (95% CI: −6%, 14%). Additionally, these data suggest that the relationship between WBGT and injury risk is non-linear with an additional 4% acceleration in risk for every degree increase in WBGT above 30 °C (95% CI: 0%, 8%). No relationship was found between daily average WBGT and risk of dehydration. Our results indicate that agricultural workers are at an increased risk of occupational injury in humid and hot environments and that businesses need to plan and adapt to increasing global temperatures by implementing and evaluating effective occupational safety and health programs to protect the health, safety, and well-being of their workers.

Effects of Pre-Cooling on Thermophysiological Responses in Elite Eventing Horses.

Simple SummaryHorses have a high metabolic capacity for exercise, producing a great deal of heat, and have a small surface area for heat loss. Under limited circumstances, the regulation of heat loss (i.e., across the respiratory tract and by the evaporation of sweat) means heat build-up in the body is reduced. Thermoregulation can be assisted by cooling the horses down to safely perform exercise in thermally challenging environments. The present study showed that pre-cooling (i.e., cooling between the warm-up and exercise performance) slightly reduced the rise in rectal, shoulder and rump skin temperatures of ten international eventing horses during moderately intense canter training in moderate environmental conditions. During the canter training, heart rate, sweat rate and sweat composition were unaffected by pre-cooling. The pre-cooling strategy chosen here was cold-water rinsing for a short period of time (~8 min). Considering the limited time and space at equestrian events, such a pre-cooling strategy could easily be implemented. Reducing heat strain by pre-cooling may potentially improve equine welfare during events.In this study, we examined the effects of pre-cooling on thermophysiological responses in horses exercising in moderate environmental conditions (average wet bulb globe temperature: 18.5 ± 3.8 °C). Ten international eventing horses performed moderate intensity canter training on two separate days, and were either pre-cooled with cold-water rinsing (5–9 °C for 8 ± 3 min; cooling) or were not pre-cooled (control). We determined velocity (V), heart rate (HR), rectal temperature (Tre,), shoulder and rump skin temperature (Tshoulder and Trump), plasma lactate concentration (LA), gross sweat loss (GSL), and local sweat rate (LSR), as well as sweat sodium, chloride and potassium concentrations. The effect of pre-cooling on Tre was dependent on time; after 20 min of exercise the effect was the largest (estimate: 0.990, 95% likelihood confidence intervals (95% CI): 0.987, 0.993) compared to the control condition, resulting in a lower median Tre of 0.3 °C. Skin temperature was also affected by pre-cooling compared to the control condition (Tshoulder: −3.30 °C, 95% CI: −3.739, −2.867; Trump: −2.31 °C, 95% CI: −2.661, −1.967). V, HR, LA, GSL, LSR and sweat composition were not affected by pre-cooling. In conclusion, pre-cooling by cold-water rinsing could increase the margin for heat storage, allowing a longer exercise time before a critical Tre is reached and, therefore, could potentially improve equine welfare during competition.

A multi-scalar climatological analysis in preparation for extreme heat at the Tokyo 2020 Olympic and Paralympic Games

ABSTRACT Extreme heat can be harmful to human health and negatively affect athletic performance. The Tokyo Olympic and Paralympic Games are predicted to be the most oppressively hot Olympics on record. An interdisciplinary multi-scale perspective is provided concerning extreme heat in Tokyo—from planetary atmospheric dynamics, including El Niño Southern Oscillation (ENSO), to fine-scale urban temperatures—as relevant for heat preparedness efforts by sport, time of day, and venue. We utilize stochastic methods to link daytime average wet bulb globe temperature (WBGT) levels in Tokyo in August (from meteorological reanalysis data) with large-scale atmospheric dynamics and regional flows from 1981 to 2016. Further, we employ a mesonet of Tokyo weather stations (2009–2018) to interpolate the spatiotemporal variability in near-surface air temperatures at outdoor venues. Using principal component analysis, two planetary (ENSO) regions in the Pacific Ocean explain 70% of the variance in Tokyo’s August daytime WBGT across 35 years, varying by 3.95°C WGBT from the coolest to warmest quartile. The 10-year average daytime and maximum intra-urban air temperatures vary minimally across Tokyo (<1.2°C and 1.7°C, respectively), and less between venues (0.6–0.7°C), with numerous events planned for the hottest daytime period (1200–1500 hr). For instance, 45% and 38% of the Olympic and Paralympic road cycling events (long duration and intense) occur midday. Climatologically, Tokyo will present oppressive weather conditions, and March–May 2020 is the critical observation period to predict potential anomalous late-summer WBGT in Tokyo. Proactive climate assessment of expected conditions can be leveraged for heat preparedness across the Game’s period.

Occupational heat stress induced health impacts: A cross-sectional study from South Indian working population

Rising temperature and heat stress risks in the changing climate scenario might potentially affect workers globally, especially the ones with strenuous workload in tropical settings. We used a cross-sectional study design to profile the heat exposures of ∼1900 workers from eight industrial sectors using a QuesTemp Wet Bulb Globe Temperature (WBGT) monitor, quantified select heat-strain indicators viz., rise in Core Body Temperature, Sweat Rate, and Urine Specific Gravity and evaluated the perceived health impacts of heat stress using a structured questionnaire. Heat exposures (average WBGT: 30.1 ± 2.6 °C) exceeded the Threshold Limit Value for 67% workers and was positively associated with the rise in Core Body Temperature >1 °C in 13% and elevated Urine Specific Gravity >1.020 in 9% workers. Heat-related health concerns were reported by 86% workers, and the heat-exposed workers had 2.3 times higher odds of adverse health outcomes compared to unexposed workers (p < 0.0001). Exposure to higher WBGT and adverse renal health among salt-pan workers were significantly associated (p = 0.004), and steel workers had 9% prevalence of kidney stones. Evidence presented clearly points to heat stress as a health and productivity risk factor that could have long-term and irreversible health impacts. In-depth assessments are urgently needed to develop scientifically sound preventative interventions and protective labor policies to avert the adverse occupational health and productivity consequences for millions of workers globally, thereby aiding poverty reduction.

Estimation of Heat Stress and Maximum Acceptable Work Time Based on Physiological and Environmental Response in Hot-Dry Climate: A Case Study in Traditional Bakers.

Background:Heat stress is common among workers in hot-dry areas. To take preventive strategies for the protection of workers against heat stress, it is important to choose a suitable index that can accurately explain environmental parameters relative to physiological responses. Objective:To evaluate heat stress and maximum acceptable work time (MAWT) based on physiological and environmental response in hot-dry climate among traditional bakers.Methods:The current study was carried out on 30 traditional bakers of 3 different bread baking systems in Ahvaz, Iran. Environmental and physiological parameters were measured simultaneously for a work shift. The work-rest time was also determined based on the relative heart rate (RHR) and the wet-bulb globe temperature (WBGT) index.Results:The average WBGT index was estimated to be higher than the standard limit for all baking stations. Despite the higher-than-the-recommended-limit WBGT index, there was no significant relationship between the WBGT index and physiological parameters. The results indicated a significant (p<0.05) difference between the percentages of work-rest time estimated using the WBGT and RHR index.Conclusion:Based on the results of environmental and physiological monitoring of this study as well as the limitations of the use of the WBGT index, it seems that using WBGT as a standard index would not suit heat stress management in hot-dry climates. A revision of this standard to adapt to hot climatic conditions should be in order.

Aerobic Exercise and Environmental Heat Stress as Adjuvants to Seasonal Influenza Vaccine

Influenza strain diversity and variability and individual immune health contribute to reduced vaccine efficacy. Among adjuvants that enhance vaccine effectiveness, several studies have examined the relationship between acute exercise stress and influenza vaccination immune responses in humans. It is proposed that acute bouts of stress enhance immune response, but optimal intervention, timing of intervention, and mechanisms have yet to be identified. As Toll‐like receptor (TLR) agonists enhance innate immune responses and support development of chronic humoral responses, exercise induced release of the TLR4 ligand lipopolysaccharide (LPS) into circulation may be a mechanism for benefit of pre‐vaccine exercise. This study aimed to assess the effects of exercise and exercise‐heat stress completed before seasonal influenza vaccination (IV) on short‐ and long‐term immune responses. Thirty‐four males (body mass, 77.41±12.48kg; age, 21.5±4.4y; maximal aerobic capacity (VO2max), 43.53±8.24mL/kg/min) were randomized into 1 of 3 groups: no exercise (NE, n=12) or 60 minutes of 60%VO2max exercise with (MEH, n=11) or without (ME, n=11) environmental heat stress. Exercise and baseline blood samples were completed 25.11±5.92h before IV, and subsequent blood samples were collected 23.45±6.13h, 13.06±2.96d, and 29.54±3.73d following IV. Exercise environmental conditions were different between ME and MEH, respectively (average wet bulb globe temperature, 32.91±2.67°C, 41.21±2.88°C; p&lt;0.001), but physiological stress was similar (average rectal temperature, 37.30±0.48°C, 27.61±1.36°C, p=0.513; heart rate, 114±105bpm, 118±105bpm, p=0.103) due to controlled exercise intensity. On‐going research will utilize hemagglutinin inhibition, cortisol, and LPS assays to quantify virus‐specific antibody responses, stress, and TLR4 activation respectively. Understanding innate and humoral responses will elucidate the potential of exercise and exercise‐heat stressors as adjuvants for IV.Support or Funding InformationNew investigator start‐up, InCHIP Interdisciplinary Seed GrantThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.