Heat-exposed Workers Research Articles

Occupational heat exposure and its impact on kidney health among cashew workers.

Rising temperatures increase workers' risk of heat-related illnesses due to heat stress (HS). Chronic Kidney Disease of unknown etiology (CKDu) is rising in non-agricultural workers in hot climates. Dehydration, heat stress, and physical exertion can damage cashew workers' kidney health. In 2020-2021, 262 cashew workers in Cuddalore, Tamil Nadu were assessed for Wet Bulb Globe Temperature (WBGT), and job-specific American Conference of Governmental Industrial Hygienists standard was used to evaluate workload. "High heat-exposed" meant heat stress exceeded the Threshold Limit Value for safe manual work (27.5°C for heavy and 28°C for moderate physical activity). Heat Strain Indicators (HSIs) such as Tympanic Temperature (Ttemp), Sweat Rate (SwR), Urine Specific Gravity (USG), and urine dipstick parameters were measured in all workers, however serum creatinine was measured only in 100 workers. Glomerular Filtration Rate(eGFR) was calculated using theCKD-EPIequation. A standardized questionnaire assessed heat-related health symptoms. Over 65% of workers experienced wet bulb globe temperature exposures exceeding the threshold limit value (Avg.- wet bulb globe temperature 30.4°C ± 1.8°C). Ninety-five percent of heat-exposed workers experienced at least one of the physiological heat strain indicators. The risk of urogenital symptoms was 7.7 times greater among high-heat-exposed workers (95% CI 3.4-17.1), which corroborates well with the measured post shift urine specific gravity (37%). Despite controlling for relevant confounders (age & gender), high-heat-exposed workers had 3.5-fold higher odds of eGFR < 90ml/min/1.73m2 compared to less-exposed workers (95% CI 1.1-10.6). Persistent heat stress promotes heat-related disorders in cashew workers and lowers eGFR. This needs further investigation to determine its longer term effects on kidney function. Workplace cooling solutions that reduce heat stress are critically needed to protect thekidneys and ensureoccupational health.

Physiological and perceptual responses to temperature step changes between cold and hot environments

Objectives. This study explores the effects of temperature steps on thermal responses to understand abrupt temperature shifts faced by heat-exposed workers during winter. Methods. Three temperature step changes with three phases (S20: 20–40–20 °C, S30: 10–40–10 °C, S40: 0–40–0 °C) were conducted. Phase 1 took 30 min, phase 2 took 60 min and phase 3 took 40 min. Eleven participants remained sedentary throughout the experiment, and physiological responses, thermal perception and self-reported health symptoms were recorded. Results. In temperature up steps, steady skin temperature and sweating onset were delayed, and heart rate dropped by 10 bpm from S20 to S40. In temperature down steps to cold conditions, individuals transitioned from thermal comfort to discomfort and eventually cold strain. Blood pressure increased in temperature down steps, correlating with temperature step magnitudes. Thermal responses to temperature steps of equal magnitude but opposite directions were asymmetries, which weakened as step magnitude increased. Thermal perceptions responded faster than physiological changes after temperature steps, while self-reported health symptoms lagged behind physiological responses. Conclusions. These findings contribute to expanding basic data to understand the effects of temperature step magnitude and direction.

A Systematic Review of Post-Work Core Temperature Cooling Rates Conferred by Passive Rest.

Physical work increases energy expenditure, requiring a considerable elevation of metabolic rate, which causes body heat production that can cause heat stress, heat strain, and hyperthermia in the absence of adequate cooling. Given that passive rest is often used for cooling, a systematic search of literature databases was conducted to identify studies that reported post-work core temperature cooling rates conferred by passive rest, across a range of environmental conditions. Data regarding cooling rates and environmental conditions were extracted, and the validity of key measures was assessed for each study. Forty-four eligible studies were included, providing 50 datasets. Eight datasets indicated a stable or rising core temperature in participants (range 0.000 to +0.028 °C min-1), and forty-two datasets reported reducing core temperature (-0.002 to -0.070 °C min-1) during passive rest, across a range of Wet-Bulb Globe Temperatures (WBGT). For 13 datasets where occupational or similarly insulative clothing was worn, passive rest resulted in a mean core temperature decrease of -0.004 °C min-1 (-0.032 to +0.013 °C min-1). These findings indicate passive rest does not reverse the elevated core temperatures of heat-exposed workers in a timely manner. Climate projections of higher WBGT are anticipated to further marginalise the passive rest cooling rates of heat-exposed workers, particularly when undertaken in occupational attire.

Diagnostic role of urine specific gravity to detect kidney impairment on heat-exposed workers in a shoe factory in Indonesia: a cross-sectional study

ObjectivesGlobally, there are increasing cases of chronic kidney disease of unknown origin among heat-exposed workers. We aimed to see the kidney damages of indoor heat-exposed workers and whether urine specific...

Heat-health vulnerabilities in the climate change context—comparing risk profiles between indoor and outdoor workers in developing country settings

Occupational heat stress is a crucial risk factor for a range of Heat-Related Illnesses (HRI). Outdoor workers in unorganized work sectors exposed to high ambient temperatures are at increased risk in developing countries. We aim to compare HRI, Productivity Loss (PL), and reduced renal health risk between workers from outdoor unorganized (N = 1053) and indoor organized (N = 1051) work sectors. Using descriptive methods and a large epidemiological cross-sectional study using mixed methods, we compared risk patterns between the two groups. We analyzed the risk of self-reported HRI symptoms, Heat Strain Indicators (HSIs), PL, and reduced kidney function using Multivariate Logistic Regression (MLR) models. Although Wet Bulb Globe Temperature (WBGT) exposures were high in both the outdoor and indoor sectors, significantly more Outdoor Unorganized Workers (OUWs) reported heat stress symptoms (45.2% vs 39.1%) among 2104 workers. OUWs had a significantly higher share of the heavy workload (86.7%) and long years of heat exposures (41.9%), the key drivers of HRIs, than the workers in indoor sectors. MLR models comparing the indoor vs outdoor workers showed significantly increased risk of HRI symptoms (Adjusted Odds Ratio) (AORoutdoor = 2.1; 95% C.I:1.60–2.77), HSI (AORoutdoor = 1.7; 95% C.I:1.00–2.93), PL (AORoutdoor = 11.4; 95% C.I:7.39–17.6), and reduced kidney function (Crude Odds Ratio) (CORoutdoor = 1.4; 95% C.I:1.10–1.84) for the OUWs. Among the heat-exposed workers, OUW had a higher risk of HRI, HSI, and PL even after adjusting for potential confounders. The risk of reduced kidney function was significantly higher among OUWs, particularly for those with heat exposures and heavy workload (AORoutdoor = 1.5; 95% C.I: 0.96–2.44, p = 0.073) compared to the indoor workers. Further, in-depth studies, protective policies, feasible interventions, adaptive strategies, and proactive mitigation efforts are urgently needed to avert health and productivity risks for a few million vulnerable workers in developing nations as climate change proceeds.

Heat exposure and kidney health of Costa Rican rice workers

Background/Aim: Chronic kidney disease of unknown etiology (CKDu) affects populations along the Pacific coast of Mesoamerica including the Guanacaste province of Costa Rica. Although the etiology of CKDu is unclear, it is known to be associated with heavy labor in hot environments. The aim of this longitudinal study was to describe heat exposure and renal health of Costa Rican rice workers over three months of production.Methods: We collected pre-shift urine and blood samples from 72 workers with different jobs in a rice company at baseline and three months later. Metabolic and ambient heat loads were measured for each job using the WBGT index (wet bulb globe temperature) and NIOSH guidelines. Serum creatinine (S-Cr, mg/dl) was used to estimate glomerular filtration rate (eGFR) as the main outcome.Results: Participants were 20-62 years old (41.2±10.3) and educational levels ranged from zero to university (mean 7 years). Most participants (90%) were dehydrated (USG≥1.025) in at least one of the two pre-shift measurements while 35% of all workers were dehydrated in both samples. At baseline mean S-Cr was 1.22 mg/dL in field workers and 1.12 mg/dL in non-field workers (p=0.083) and three months later levels were 1.35 mg/dL and 1.12 mg/dL respectively (p=0.008). The only predictor of low eGFR identified using multiple logistic regression analysis was being a field worker. Low eGFR was seen in 18.5% of field workers and 4.3% of non-field workers at baseline. Three months later, when workloads were higher, 25.6% of field workers (n=7) and 6.7% of non-field workers (n=4) had low eGFR (p=0.034).Conclusions: Dehydration was quite common in this study. Low eGFR was particularly prevalent in field workers in heat stress conditions. There is an urgent need to continue to improve efforts to provide adequate water, rest and shade for heat-exposed workers in accordance with national regulations.

Epidemiological evidence from south Indian working population—the heat exposures and health linkage

Changing climate and rising temperatures are predicted to affect millions of workers due to heat stress risks, especially in tropical settings. We used a cross-sectional study design to profile the heat exposures of ~1500 workers from eight-industrial sectors using a QuesTemp wet bulb globe temperature (WBGT) monitor, quantified the heat-strain indicators viz., rise in Core Body Temperature (CBT), Sweat Rate (SwR), and Urine Specific Gravity (USG) by standard methods and evaluated the health impacts of heat stress using a structured questionnaire. Heat exposures (Avg.WBGT: 28.4 ± 2.6 °C) exceeded the Threshold Limit Value (TLV) for 70% of workers and was significantly associated with the rise in CBT >1 °C in 11.3% and elevated USG >1.020 in 10.5% of the workers. The heat-exposed workers had 2.3 times higher odds of reporting adverse health outcomes (84%) compared to the unexposed workers (95% CI: 1.74-3.19; p value ≤ 0.0001). Mild reduction in kidney function observed in 49% of salt -pan workers, and a high prevalence of kidney stones (33%) among the 91 steelworkers subjected to kidney ultrasound had a significant association with chronic high WBGT exposure above the TLV (p value < 0.034). Further, in-depth assessments are warranted to develop strategies for interventions and protective labor policies to avert adverse occupational health and productivity consequences for millions of workers globally, especially in the rising temperature scenario.

Risk of kidney stone among workers exposed to high occupational heat stress - A case study from southern Indian steel industry

BackgroundPredicted temperature rise is likely to increase the risks of development and progression of renal/urologic anomalies for workers engaged in physically exerting and high-heat occupations. MethodsWe conducted a cross-sectional study with 340 steelworkers engaged in moderate to heavy labour with ≥3 year's heat exposures and assessed Wet Bulb Globe Temperature (WBGT) and heat-strain indicators. We captured self-reported heat-strain and kidney symptoms using validated questionnaires and subjected 91 workers to renal ultrasound upon referral of an occupational health specialist to detect and confirm any structural renal anomalies/stones. ResultsThe results show that heat exposures (Avg.WBGT = 33.2 °C ± 3.8 °C) exceeded the Threshold Limit Value (TLV) for 220 workers. 95% of the workers reported symptoms of heat strain and dehydration and significant associations between heat exposures, rise in Core Body Temperature (CBT) (p = 0.0001) and Urine Specific Gravity (USG) (p = 0.018) were observed. Of the 91 workers subjected to renal ultrasound, 33% were positive for kidney/ureteral stones (n = 25) & other structural renal anomalies (n = 5). Renal/urologic anomalies were higher in the heat-exposed workers (AOR = 2.374; 95% C.I = 0.927 to 6.077; p = 0.072) 29% of workers were from exposed group and 4% were from unexposed group. Years of exposure to heat (≥5 vs <5) were significantly associated with the risk of renal anomalies/calculi. ConclusionThe preliminary finding concludes that high-heat stress combined with a heavy workload and chronic dehydration are high-risk factors for adverse renal health and calls for the urgent need for cooling interventions, enhanced welfare facilities, and protective labour policies to avert adverse health consequences for few million workers in the climate change scenario.

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.

Heat stress monitoring based on heart rate measurements.

Currently, occupational heat exposure is usually measured using environmental variables such as the wet bulb globe temperature index. The costs of heat stress monitoring include the acquisition of specialized equipment and the recruitment of trained personnel. In rapidly changing environments, such as outdoor settings, these assessments must be conducted on a daily basis. The wet bulb globe temperature index has been criticized as a measure of heat stress for its failure to account for individual differences in susceptibility to heat stress, age, body mass index, physical fitness, clothing, illnesses and use of alcohol or drugs. The objective of this study was to assess the relationship between heart rate and body temperature in heat-exposed workers to determine whether heart rate can be used to monitor and prevent heat stress and physiological strain. This study was based on previous literature as well as physiological and environmental data collected from 10 individuals engaged in heavy physical labor. Heart rate, which has been recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) as a possible measure of heat stress, follows a similar trend to body temperature with a slight temporal delay. Heart rate monitors with alarm systems could be developed to notify workers when to slow down their activities or take a break for thermal recovery, thereby contributing to the prevention of heat-related illness.

Study on High-Temperature Working Environment with the Excretion and the Levels &lt;i&gt;In Vivo&lt;/i&gt; of Vitamin C among Heat-Exposed Workers

In order to study the effect of high temperature working environment on the vitamin C excretion of steel workers and the levels in vivo, we survey and analyze vitamin C in sweat and urine from the 226 heat-exposed workers and 39 non-heat-exposed workers at the same workshop. The results of the survey show that sweating is the main way for the excretion of vitamin C under the high temperature environment, and this is also one of the main reasons for the in vivo levels of vitamin C declining. Consequently, some necessary measures should be taken to avoid damage caused by heat-exposed operation and ensure the workers enjoy good health.

Safety in the Heat: A Comprehensive Program for Prevention of Heat Illness Among Workers in Abu Dhabi, United Arab Emirates

The Safety in the Heat program was developed in response to the extreme heat stress conditions experienced by workers in the United Arab Emirates and other Middle Eastern countries each summer, where ambient air temperatures often reach 45°C (135°F) and higher with 90% humidity. A comprehensive, multimedia, economical education and awareness program targeting companies in the region was developed; 465 companies employing 814 996 heat-exposed workers across 6254 work and labor residence sites were reached. Feedback from program participants indicated a high level of support and satisfaction. Results indicated a marked reduction in heat related illness over a period of 2 years (2008-2009) at 2 companies, one of which reported a combined 79.5% decrease in cases (15.3 vs 1.16 cases per 1000 workers) while the other experienced a 50% reduction in serious cases (0.08-0.04 cases per 100,000 work hours).

CARDIO-PROTECTIVE ROLE OF HEAT SHOCK PROTEIN 70 (HSP 70) AMONG HEAT-EXPOSED WORKERS

Aim: This work aimed at studying the prevalence of ischemic heart diseases (IHD) among heat-exposed workers and the extent of having the high risk factors particularly dyslipidemia and hypertension among this group of workers. Besides, the cardioprotective role of heat shock protein 70 (HSP 70), as a molecular heat exposure biomarker, was clarified. Subjects: The study subjects consisted of a heat-exposed 29 bakers group employed in 10 manual bakeries and a matched heat unexposed group (n= 29). Methods: Every individual underwent occupational and clinical history taking,resting electrocardiogram (ECG), estimation of serum lipid profile parameters,{ total cholesterol (TC), high density lipoprotein (HDL-C), TC/HDL-C ratio, low density lipoprotein (LDL-C), triglycerides (TG)} and heat shock protein 70 (HSP70). Results: Analysis of history showed significantly higher prevalence of heat cramps ( 27.5%) andheat rash ( 34.5%) among the heat-exposed group. Resting ECG revealed ischemic manifestations in 20.6% of the heat-exposed workers versus 13.7% of their controls (P<0.05). Marked significant increase in all lipid profile parameters was detected in the heat-exposed individuals with positive correlation with duration of work. The HSP 70 level was 2 times higher among the heat-exposed group. The individuals having ischemic manifestations had lower HSP70 level. Conclusion: Working in hot environments can induce unfavorable increase in blood lipids which predisposes workers to IHD. As HSP 70 which is known to have a cardio-protective role declines with age with consequent diminishing of its cardio-protective role, elderly workers exposed to heat would have higher incidence of IHD which necessitates avoidance of working under hot conditions.

Ambient-Temperature Beverages Are Consumed at a Rate Similar to Chilled Water in Heat-Exposed Workers

Palatability of beverages has been shown to influence drinking patterns and hydration. Cool beverages are known to enhance palatability; however, situations exist in which cooling is not possible. The purpose of this study was to determine the palatability of a variety of flavors of ambient temperature beverages. Ten healthy males performed two work trials in a temperature-controlled environment (WBGT = 30°C; wet = 25°C, dry = 40°C, globe = 41°C). In one trial, the subjects had only chilled water to drink. In the second trial the subjects drank their choice (any or all) of five ambient temperature beverages (water, fruit punch, lemon-lime, orange, and cola). Repeated measures ANOVA showed no difference in absolute or relative fluid consumption between the two trials (chilled = 1730 ± 316 mL and 21 ± 5 mL/kg; ambient [all five beverages combined] = 1510 ± 219 mL and 19 ± 4 mL/kg). There was no difference in the rate of fluid consumption between the two trials (608 ± 88 mL/30 min and 674 ± 82 mL/30 min, p > 0.05). Additionally, when combining all ambient-temperature, flavored beverages, consumption was significantly greater than that of ambient temperature water (1245 ± 206 vs. 255 ± 86 mL, p < 0.05). These findings demonstrate that providing ambient temperature beverages in a hot condition results in fluid consumption values similar to chilled water. These findings are relevant to industry in that there may be times when workers are at risk for heat-related illness due to dehydration and chilled beverages are not available. By providing flavored beverages, fluid consumption may be maintained and degree of heat-illness may be lessened.

Fluid Replacement Preferences in Heat-Exposed Workers

Fluid Replacement Preferences in Heat-Exposed Workers

Effects of work and motivation on the heart rates of chronic heat-exposed workers during their regular work shifts.

Heart rate is accepted as one of the best indices of physiological strain imposed by physical and environmental stressors. Continuous recordings of ECG were taken in mid-summer and mid-winter from metal workshop workers during their regular 8 hour work shifts at the work area in two plants located in the desert in Israel. Seven workers were studied in Beer Sheva, a semi-arid zone with average daily maximum temperature in the two seasons of 38 and 25°C. Twenty-four worked near the Dead Sea at Sdom, an extreme desert, with corresponding temperatures of 44 and 26°C. The workers in Beer Sheva were motivated to work hard and increase productivity in order to augment their low salaries. No such motivation existed in the plant in Sdom, whose workers were highly paid. Contrary to the expected, the comparison of the heart-rate profiles of the two seasons showed no differences in Sdom while in Beer Sheva, winter heart rates were higher than in summer. In both plants, in both seasons during at least 50% of the work ...