A Field Evaluation of Construction Workers’ Activity, Hydration Status, and Heat Strain in the Extreme Summer Heat of Saudi Arabia

2020 ◽  
Vol 64 (5) ◽  
pp. 522-535 ◽  
Author(s):  
Mohammed Al-Bouwarthan ◽  
Margaret M Quinn ◽  
David Kriebel ◽  
David H Wegman

Abstract Objectives Assess the impact of summer heat exposure (June–September) on residential construction workers in Al-Ahsa, Saudi Arabia by evaluating (i) heart rate (HR) responses, hydration status, and physical workload among workers in indoor and outdoor construction settings, (ii) factors related to physiological responses to work in hot conditions, and (iii) how well wet-bulb globe temperature-based occupational exposure limits (WBGTOELs) predict measures of heat strain. Methods Twenty-three construction workers (plasterers, tilers, and laborers) contributed 260 person-days of monitoring. Workload energy expenditure, HR, fluid intake, and pre- and postshift urine specific gravity (USG) were measured. Indoor and outdoor heat exposures (WBGT) were measured continuously and a WBGTOEL was calculated. The effects of heat exposure and workload on heart rate reserve (HRR), a measure of cardiovascular strain, were examined with linear mixed models. A metric called ‘heat stress exceedance’ (HSE) was constructed to summarize whether the environmental heat exposure (WBGT) exceeded the heat stress exposure limit (WBGTOEL). The sensitivity and specificity of the HSE as a predictor of cardiovascular strain (HRR ≥30%) were determined. Results The WBGTOEL was exceeded frequently, on 63 person-days indoors (44%) and 91(78%) outdoors. High-risk HRR occurred on 26 and 36 person-days indoors and outdoors, respectively. The HSE metric showed higher sensitivity for HRR ≥30% outdoors (89%) than indoors (58%) and greater specificity indoors (59%) than outdoors (27%). Workload intensity was generally moderate, with light intensity work more common outdoors. The ability to self-pace work was associated with a lower frequency of HRR ≥30%. USG concentrations indicated that workers began and ended their shifts dehydrated (USG ≥1.020). Conclusions Construction work where WBGTOEL is commonly exceeded poses health risks. The ability of workers to self-pace may help reduce risks.

Author(s):  
Mohammed Al-Bouwarthan ◽  
Margaret M. Quinn ◽  
David Kriebel ◽  
David H. Wegman

Saudi Arabia (SA) is one of the hottest countries in the world. This study was conducted to assess the impact of summer heat stress in Southeastern SA on short-term kidney injury (KI) among building construction workers and to identify relevant risk factors. Measurements of urinary albumin-creatinine ratio (ACR), height, weight, hydration, symptoms, daily work and behavioral factors were collected in June and September of 2016 from a cohort of construction workers (n = 65) in Al-Ahsa Province, SA. KI was defined as ACR ≥ 30 mg/g. Multivariate linear regression analysis was used to assess factors related to cross-summer changes in ACR. A significant increase in ACR occurred among most workers over the study period; incidence of KI was 18%. Risk factors associated with an increased ACR included dehydration, short sleep, and obesity. The findings suggest that exposure to summer heat may lead to the development of KI among construction workers in this region. Adequate hydration and promotion of healthy habits among workers may help reduce the risk of KI. A reduction in work hours may be the most effective intervention because this action can reduce heat exposure and improve sleep quality.


2019 ◽  
Vol 63 (5) ◽  
pp. 505-520 ◽  
Author(s):  
Mohammed Al-Bouwarthan ◽  
Margaret M Quinn ◽  
David Kriebel ◽  
David H Wegman

Abstract Objectives Excessive heat exposure poses significant risks to workers in hot climates. This study assessed the intensity and duration of heat stress exposure among workers performing residential construction in southeastern Saudi Arabia (SA) during the summer, June–September 2016. Objectives were to: identify work factors related to heat stress exposure; measure environmental heat exposure at the construction sites; assess the heat stress risk among workers using the wet bulb globe temperature (WBGT) index; and determine if temperature-humidity indices can be appropriate alternatives to WBGT for managing heat stress risk at the construction sites. Methods Worksite walkthrough surveys and environmental monitoring were performed, indoors and outdoors, at 10 construction sites in Al-Ahsa Province. A heat stress exposure assessment was conducted according to the American Conference of Governmental Industrial Hygienists (ACGIH®) guidelines, which uses the WBGT index. WBGT measurements from two instruments were compared. Alternative heat stress indices were compared to the WBGT: the heat index (HI) and humidex (HD) index. Results Construction workers were exposed to excessive heat stress, indoors and outdoors over a large part of the work day. Complying with a midday outdoor work ban (12–3 p.m.) was not effective in reducing heat stress risk. The highest intensity of exposure was outdoors from 9 a.m. to 12 p.m.; a period identified with the highest hourly mean WBGT values (31–33°C) and the least allowable working time according to ACGIH® guidelines. Comparison of the alternative indices showed that the HI is more reliable than the HD as a surrogate for the WBGT index in the climate studied. Conclusion The extreme heat exposure represents a serious risk. The severity of heat stress and its impact are projected to increase due to climate change, emphasizing the need for immediate improvement of the current required protective measures and the development of occupational heat stress exposure guidelines in SA.


Author(s):  
Pongsit Boonruksa ◽  
Thatkhwan Maturachon ◽  
Pornpimol Kongtip ◽  
Susan Woskie

Prolonged or intense exposure to heat can lead to a range of health effects. This study investigated heat exposure and heat-related symptoms which sugarcane workers (90 sugarcane cutters and 93 factory workers) experienced during a harvesting season in Thailand. During the hottest month of harvesting season, wet bulb globe temperature was collected in the work environment, and workloads observed, to assess heat stress. Urine samples for dehydration test, blood pressure, heart rate, and body temperature were measured pre- and post-shift to measure heat strain. Fluid intake and heat-related symptoms which subjects had experienced during the harvesting season were gathered via interviews at the end of the season. From the results, sugarcane cutters showed high risk for heat stress and strain, unlike factory workers who had low risk based on the American Conference of Governmental Industrial Hygiene (ACGIH) threshold limit values (TLVs) for heat stress. Dehydration was observed among sugarcane cutters and significant physiological changes including heart rate, body temperature, and systolic blood pressure occurred across the work shift. Significantly more sugarcane cutters reported experiencing heat-related symptoms including weakness/fatigue, heavy sweating, headache, rash, muscle cramp, dry mouth, dizziness, fever, dry/cracking skin, and swelling, compared to sugarcane factory workers. We conclude that the heat stress experienced by sugarcane cutters working in extremely hot environments, with high workloads, is associated with acute health effects. Preventive and control measures for heat stress are needed to reduce the risk of heat strain.


2005 ◽  
Vol 30 (7) ◽  
pp. 495-502 ◽  
Author(s):  
Robert Carter ◽  
Samuel N. Cheuvront ◽  
D.Walter Wray ◽  
Margaret A. Kolka ◽  
Lou A. Stephenson ◽  
...  

2020 ◽  
Vol 5 ◽  
pp. 32
Author(s):  
Ana Bonell ◽  
Jane Hirst ◽  
Ana M. Vicedo-Cabrera ◽  
Andy Haines ◽  
Andrew M. Prentice ◽  
...  

Introduction: Climate change predictions indicate that global temperatures are likely to exceed those seen in the last 200,000 years, rising by around 4°C above pre-industrial levels by 2100 (without effective mitigation of current emission rates). In regions of the world set to experience extreme temperatures, women often work outside in agriculture even during pregnancy. The implications of heat strain in pregnancy on maternal health and pregnancy outcome are not well understood. This protocol describes a study to assess the physiological response of pregnant women to environmental heat stress and the immediate effect this has on fetal wellbeing. Methods and analysis: The study will be performed in West Kiang district, The Gambia; a semi-arid zone in West Africa with daily maximum temperatures ranging from approximately 32 to 40°C. We will recruit 125 pregnant women of all ages who perform agricultural work during their pregnancy. Participants will be followed every two months until delivery. At each study visit fetal growth will be measured by ultrasound scan. During the course of their working day we will take the following measurements: continuous maternal physiological measurements (heart rate, respiratory rate, chest skin temperature and tri-axis accelerometer data); intermittent maternal tympanic core temperature, four point skin temperature, blood pressure; intermittent fetal heart rate and, if eligible, umbilical artery doppler; intermittent environmental measurements of air temperature, humidity, solar radiation and wind speed. Venous blood and urine will be collected at beginning and end of day for biomarkers of heat strain or fetal distress and hydration status.


1994 ◽  
Vol 77 (1) ◽  
pp. 216-222 ◽  
Author(s):  
S. J. Montain ◽  
M. N. Sawka ◽  
B. S. Cadarette ◽  
M. D. Quigley ◽  
J. M. McKay

This study determined the influence of exercise intensity, protective clothing level, and climate on physiological tolerance to uncompensable heat stress. It also compared the relationship between core temperature and the incidence of exhaustion from heat strain for persons wearing protective clothing to previously published data of unclothed persons during uncompensable heat stress. Seven heat-acclimated men attempted 180-min treadmill walks at metabolic rates of approximately 425 and 600 W while wearing full (clo = 1.5) or partial (clo = 1.3) protective clothing in both a desert (43 degrees C dry bulb, 20% relative humidity, wind 2.2 m/s) and tropical (35 degrees C dry bulb, 50% relative humidity, wind 2.2 m/s) climate. During these trials, the evaporative cooling required to maintain thermal balance exceeded the maximal evaporative capacity of the environment and core temperature continued to rise until exhaustion from heat strain occurred. Our findings concerning exhaustion from heat strain are 1) full encapsulation in protective clothing reduces physiological tolerance as core temperature at exhaustion was lower (P < 0.05) in fully than in partially clothed persons, 2) partial encapsulation results in physiological tolerance similar to that reported for unclothed persons, 3) raising metabolic rate from 400 to 600 W does not alter physiological tolerance when subjects are fully clothed, and 4) physiological tolerance is similar when subjects are wearing protective clothing in desert and tropical climates having the same wet bulb globe thermometer. These findings can improve occupational safety guidelines for human heat exposure, as they provide further evidence that the incidence of exhaustion from heat strain can be predicted from core temperature.


1987 ◽  
Vol 108 (3) ◽  
pp. 549-553 ◽  
Author(s):  
N. Chaiyabutr ◽  
C. Buranakarl ◽  
V. Muangcharoen ◽  
P. Loypetjra ◽  
A. Pichaicharnarong

SummaryDuring 5 h of acute heat exposure (41 °C), there were increases in the heart rate from 43±2 (S.E.) to 51 ± 1 beats/min, respiratory rate from 26±4 to 86± 16 breaths/min and rectal temperature from 38·5 ± 0·1 °C to 39·7 ± 0·2 °C. The flow rate of liquid from the rumen and body water turnover significantly increased while biological half life of chromium-51 ethylenediaminetetra-acetate in the rumen and tritiated water decreased from 12·9 ± 2·5 and 87·7 ± 6·8 h to 9·3 ± 2·0 and 49·2 ± 5·7 h respectively. An increase in blood volume during acute heat stress occurred with an increase of both plasma and cell volume. An elevation of plasma water coincided with an increase in plasma protein and glucose. There is evidence that the increase in plasma water during heat exposure came from extravascular tissue space and/or from the digestive tract.


2020 ◽  
Vol 5 ◽  
pp. 32
Author(s):  
Ana Bonell ◽  
Jane Hirst ◽  
Ana M. Vicedo-Cabrera ◽  
Andy Haines ◽  
Andrew M. Prentice ◽  
...  

Introduction: Climate change predictions indicate that global temperatures are likely to exceed those seen in the last 200,000 years, rising by around 4°C above pre-industrial levels by 2100 (without effective mitigation of current emission rates). In regions of the world set to experience extreme temperatures, women often work outside in agriculture even during pregnancy. The implications of heat strain in pregnancy on maternal health and pregnancy outcome are not well understood. This protocol describes a study to assess the physiological response of pregnant women to environmental heat stress and the immediate effect this has on fetal wellbeing. Methods and analysis: The study will be performed in West Kiang district, The Gambia; a semi-arid zone in West Africa with daily maximum temperatures ranging from approximately 32 to 40°C. We will recruit 125 pregnant women of all ages who perform agricultural work during their pregnancy. Participants will be followed every two months until delivery. At each study visit fetal growth will be measured by ultrasound scan. During the course of their working day we will take the following measurements: continuous maternal physiological measurements (heart rate, respiratory rate, chest skin temperature and tri-axis accelerometer data); intermittent maternal tympanic core temperature, four point skin temperature, blood pressure; intermittent fetal heart rate and, if eligible, umbilical artery doppler; intermittent environmental measurements of air temperature, humidity, solar radiation and wind speed. Venous blood and urine will be collected at beginning and end of day for biomarkers of heat strain or fetal distress and hydration status.


1961 ◽  
Vol 16 (1) ◽  
pp. 144-152 ◽  
Author(s):  
Joseph Gold

A system for the evaluation and selection of heat stress candidates has been developed that is concerned not only with the extent to which an individual is capable of dissipating heat, but also the price he must pay for so doing. The former is dealt with through the concept of effective body heat storage ( qe); the latter, through a newly developed index of strain ( IG). Effective body heat storage is defined as that amount of storage obtained if a subject were able to go into a heat chamber already fully equilibrated with it and with all heat-dissipating mechanisms fully operating. The index attempts to express a new concept, accumulative circulatory strain, in terms of heart rate alone. The best subjects (usually in the young age groups) show a low ( IG) and low ( IG); the worst (usually in the older age groups) show a high ( qe) and low ( IG). All subjects were maintained at rest during heat exposure. Submitted on April 8, 1960


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