scholarly journals Occupational Heat Stress: Multi-Country Observations and Interventions

2021 ◽  
Vol 18 (12) ◽  
pp. 6303
Author(s):  
Leonidas G. Ioannou ◽  
Konstantinos Mantzios ◽  
Lydia Tsoutsoubi ◽  
Eleni Nintou ◽  
Maria Vliora ◽  
...  
Keyword(s):  
Heat Stress ◽  
Labor Productivity ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Heat Strain ◽  
Physiological Strain ◽  
Industrial Sectors ◽  
Work Shifts ◽  
Core Body ◽  
Occupational Heat Exposure

Background: Occupational heat exposure can provoke health problems that increase the risk of certain diseases and affect workers’ ability to maintain healthy and productive lives. This study investigates the effects of occupational heat stress on workers’ physiological strain and labor productivity, as well as examining multiple interventions to mitigate the problem. Methods: We monitored 518 full work-shifts obtained from 238 experienced and acclimatized individuals who work in key industrial sectors located in Cyprus, Greece, Qatar, and Spain. Continuous core body temperature, mean skin temperature, heart rate, and labor productivity were collected from the beginning to the end of all work-shifts. Results: In workplaces where self-pacing is not feasible or very limited, we found that occupational heat stress is associated with the heat strain experienced by workers. Strategies focusing on hydration, work-rest cycles, and ventilated clothing were able to mitigate the physiological heat strain experienced by workers. Increasing mechanization enhanced labor productivity without increasing workers’ physiological strain. Conclusions: Empowering laborers to self-pace is the basis of heat mitigation, while tailored strategies focusing on hydration, work-rest cycles, ventilated garments, and mechanization can further reduce the physiological heat strain experienced by workers under certain conditions.

The effects of heat stress on cognition in persons with multiple sclerosis

2011 ◽  
Vol 18 (4) ◽  
pp. 489-497 ◽  
Author(s):  
P Hämäläinen ◽  
A Ikonen ◽  
A Romberg ◽  
H Helenius ◽  
J Ruutiainen
Keyword(s):  
Multiple Sclerosis ◽  
Heat Stress ◽  
Body Temperature ◽  
Cognitive Functioning ◽  
Cognitive Deficits ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Heat Sensitivity ◽  
Serial Addition ◽  
Core Body

Background: Heat sensitivity and cognitive deficits are typical manifestations of multiple sclerosis (MS). Although cognitive deficits are quite well characterized, practically no data exist on the effects of heat on cognitive performances in MS. Objective: To assess the effects of short-term heat stress on cognitive functioning in subjects with MS. Methods: A total of 23 heat-sensitive MS and 19 healthy control (HC) subjects participated. Moderate heat exposure took place in a Finnish sauna. Cognitive functioning was measured with tests of sustained attention and processing speed, the Paced Auditory Serial Addition Test (PASAT 3” and 2”) and the computerized visual vigilance test, before, during and after heat exposure. Results: During the heat exposure, the core body temperature of the MS group rose significantly more ( p = 0.002) than that of the HC group. The heat stress worsened the performance of the MS group in the PASAT 3” ( p = 0.025) but not in the other cognitive measures. The performance in the PASAT 3” was reversed almost to the baseline level only 1- h after the heat exposure. Conclusions: A significant increase in core body temperature during heat stress is associated with a mild and reversible worsening of the PASAT 3” performance, while visual vigilance performance seems to remain almost unaffected.

scholarly journals An Occupational Heat Stress and Hydration Assessment of Agricultural Workers in North Mexico

2020 ◽  
Vol 17 (6) ◽  
pp. 2102
Author(s):  
Rietta S. Wagoner ◽  
Nicolas I. López-Gálvez ◽  
Jill G. de Zapien ◽  
Stephanie C. Griffin ◽  
Robert A. Canales ◽  
...  
Keyword(s):  
Heat Stress ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Agricultural Workers ◽  
Hydration Status ◽  
Southern Mexico ◽  
Agricultural Industry ◽  
Targeted Interventions ◽  
Northern Mexico ◽  
Core Body

Expanding agribusiness in Northern Mexico has increased demand for workers from Southern Mexico, with hundreds of thousands migrating for work annually. Extreme temperatures, physical labor, and low fluid consumption place workers at risk for heat strain and dehydration, commonly underreported hazards in the agricultural industry. The objectives of this pilot study were to assess heat exposure and hydration status of a population of migratory agricultural workers in Northern Mexico throughout the grape harvest season. In addition to demographic information, environmental conditions, hydration status, and core body temperatures were collected. The majority listed Chiapas as their home state, nearly half spoke an Indigenous language, and none had completed high school. The wet-bulb globe temperature was significantly higher during the harvest and post-harvest seasons compared to the pre-harvest season. Across the different seasons, the majority were dehydrated post-shift, and mean core body temperature of workers was not significantly different. This project highlights the need for targeted interventions to improve hydration and prevent heat stress in this region. As the number of warm days is expected to rise each year worldwide, it will be increasingly important to engage in practices to protect vulnerable populations, such as migratory agriculture workers.

Hydration effects on physiological strain of horses during exercise-heat stress

1998 ◽  
Vol 84 (6) ◽  
pp. 2042-2051 ◽  
Author(s):  
Raymond J. Geor ◽  
Laura Jill McCutcheon
Keyword(s):  
Heat Stress ◽  
Body Temperature ◽  
Oral Fluid ◽  
Heat Storage ◽  
Core Body Temperature ◽  
Thermal Strain ◽  
Fluid Replacement ◽  
Physiological Strain ◽  
Exercise Induced ◽  
Core Body

This study examined the effects of hyperhydration, exercise-induced dehydration, and oral fluid replacement on physiological strain of horses during exercise-heat stress. On three occasions, six horses completed a 90-min exercise protocol (50% maximal O2 uptake, 34.5°C, 48% relative humidity) divided into two 45-min periods ( exercise I and exercise II) with a 15-min recovery between exercise bouts. In random order, horses received no fluid (NF), 10 liters of water (W), or a carbohydrate-electrolyte solution (CE) 2 h before exercise and between exercise bouts. Compared with NF, preexercise hyperhydration (W and CE) did not alter heart rate, cardiac output (Q˙), stroke volume (SV), core body temperature, sweating rate (SR), or sweating sensitivity during exercise I. In contrast, after exercise II, exercise-induced dehydration in NF (decrease in body mass: NF, 5.6 ± 0.8%; W, 1.1 ± 0.4%; CE, 1.0 ± 0.2%) resulted in greater heat storage, with core body temperature ∼1.0°C higher compared with W and CE. In exercise II, the greater thermal strain in NF was associated with significant ( P < 0.05) decreases inQ˙ (10 ± 2%), SV (9 ± 3%), SR, and sweating sensitivity. We concluded that 1) preexercise hyperhydration provided no thermoregulatory advantage; 2) maintenance of euhydration by oral fluid replacement (∼85% of sweat fluid loss) during exercise in the heat was reflected in higher Q˙, SV, and SR with decreased heat storage; and 3) W or an isotonic CE solution was equally effective in reducing physiological strain associated with exercise-induced dehydration and heat stress.

scholarly journals A novel mouse model of heatstroke accounting for ambient temperature and relative humidity

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kazuyuki Miyamoto ◽  
Keisuke Suzuki ◽  
Hirokazu Ohtaki ◽  
Motoyasu Nakamura ◽  
Hiroki Yamaga ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Temperature ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Organ Damage ◽  
Core Body ◽  
The Impact ◽  
Treatment Water

Abstract Background Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure. Methods Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS. Results The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage. Conclusions We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.

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
Keyword(s):  
Heart Rate ◽  
Saudi Arabia ◽  
Heat Stress ◽  
Heat Exposure ◽  
Heat Strain ◽  
Construction Workers ◽  
Hydration Status ◽  
Summer Heat ◽  
Cardiovascular Strain ◽  
Indoor And Outdoor

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.

scholarly journals Thermoregulatory Influence of a Cooling Vest on Hyperthermic Athletes

2008 ◽  
Vol 43 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Rebecca M. Lopez ◽  
Michelle A. Cleary ◽  
Leon C. Jones ◽  
Ron E. Zuri
Keyword(s):  
Heat Stress ◽  
Cooling Rate ◽  
Core Body Temperature ◽  
Athletic Trainers ◽  
Water Immersion ◽  
Standard Of Care ◽  
Humid Environment ◽  
Randomized Control ◽  
Ice Water ◽  
Core Body

Abstract Context: Athletic trainers must have sound evidence for the best practices in treating and preventing heat-related emergencies and potentially catastrophic events. Objective: To examine the effectiveness of a superficial cooling vest on core body temperature (Tc) and skin temperature (Tsk) in hypohydrated hyperthermic male participants. Design: A randomized control design with 2 experimental groups. Setting: Participants exercised by completing the heat-stress trial in a hot, humid environment (ambient temperature  =  33.1 ± 3.1°C, relative humidity  =  55.1 ± 8.9%, wind speed  =  2.1 ± 1.1 km/hr) until a Tc of 38.7 ± 0.3°C and a body mass loss of 3.27 ± 0.1% were achieved. Patients or Other Participants: Ten healthy males (age  =  25.6 ± 1.6 years, mass  =  80.3 ± 13.7 kg). Intervention(s): Recovery in a thermoneutral environment wearing a cooling vest or without wearing a cooling vest until Tc returned to baseline. Main Outcome Measure(s): Rectal Tc, arm Tsk, time to return to baseline Tc, and cooling rate. Results: During the heat-stress trial, Tc significantly increased (3.6%) and, at 30 minutes of recovery, Tc had decreased significantly (2.6%) for both groups. Although not significant, the time for return to baseline Tc was 22.6% faster for the vest group (43.8 ± 15.1 minutes) than for the no-vest group (56.6 ± 18.0 minutes), and the cooling rate for the vest group (0.0298 ± 0.0072°C/min) was not significantly different from the cooling rate for the no-vest group (0.0280 ± 0.0074°C/min). The Tsk during recovery was significantly higher (2.1%) in the vest group than in the no-vest group and was significantly lower (7.1%) at 30 minutes than at 0 minutes for both groups. Conclusions: We do not recommend using the cooling vest to rapidly reduce elevated Tc. Ice-water immersion should remain the standard of care for rapidly cooling severely hyperthermic individuals.

A Real-Time Case Study in Driver Science: Physiological Strain and Related Variables

2015 ◽  
Vol 10 (8) ◽  
pp. 1058-1060 ◽  
Author(s):  
Edward S. Potkanowicz
Keyword(s):  
Body Temperature ◽  
Real Time ◽  
Core Body Temperature ◽  
Time Data ◽  
Physiological Strain ◽  
Physiological Strain Index ◽  
Probe System ◽  
Future Work ◽  
Core Body

This case study was conducted as an attempt to quantify racecar-driver core body temperature and heart rate (HR) in real time on a minute-by-minute basis and to expand the volume of work in the area of driver science. Three drivers were observed during a 15-lap, 25-min maximal event. Each driver competed in the closed-wheel, closed-cockpit sports-car category. Data on core body temperature and HR were collected continuously using the HQ Inc. ingestible core probe system and HR monitoring. Driver 1 pre- and postrace core temperatures were 37.80°C and 38.79°C, respectively. Driver 2 pre- and postrace core temperatures were 37.41°C and 37.99°C. Driver 1 pre- and postrace HRs were 102 and 161 beats/min. Driver 2 pre- and postrace HRs were 94.3 and 142 beats/min. Driver 1’s physiological strain index (PSI) at the start was 3.51. Driver 2’s PSI at the start was 3.10. Driver 1 finished with a PSI of 7.04 and driver 2 with a PSI of 3.67. Results show that drivers are continuously challenged minute by minute. In addition, before getting into their cars, the drivers already experience physiological and thermal challenges. The data suggest that drivers are getting hot quickly. In longer events, this represents the potential for severe heat injury. Investigating whether the HRs observed are indicative of work or evidence of a thermoregulatory-associated challenge is a direction for future work. The findings support the value of real-time data collection and offer strong evidence for the expansion of research on driver-athletes.

scholarly journals Genetic parameters for hair characteristics and core body temperature in a multibreed Brahman–Angus herd1

2019 ◽  
Vol 97 (8) ◽  
pp. 3246-3252 ◽  
Author(s):  
Kaitlyn M Sarlo Davila ◽  
Heather Hamblen ◽  
Peter J Hansen ◽  
Serdal Dikmen ◽  
Pascal A Oltenacu ◽  
...  
Keyword(s):  
Heat Stress ◽  
Body Temperature ◽  
Genetic Parameters ◽  
Core Body Temperature ◽  
Cattle Breed ◽  
Measuring Device ◽  
Hair Samples ◽  
Diameter Core ◽  
Humidity Index ◽  
Core Body

Abstract Thermal stress in hot humid conditions limits cattle production. The objectives for this study were to estimate genetic parameters for hair characteristics and core body temperature under low and high temperature humidity index (THI) conditions. Hair samples were collected and measured for length and diameter. Core body temperature was measured as vaginal temperature every 15 min over a 5-d period using an iButton temperature measuring device implanted in a blank CIDR in 336 heifers from the University of Florida multibreed herd (ranging from 100% Angus to 100% Brahman). Restricted maximum likelihood procedures were used to estimate heritabilities from multiple bivariate animal models using the WOMBAT program. Estimates of heritability for hair diameter, undercoat length, topcoat length, body temperature under low THI conditions, and body temperature under high THI conditions were 0.50, 0.67, 0.42, 0.32, and 0.26, respectively. The genetic parameters estimated in this study indicate a large, exploitable genetic variance which can be selected upon to improve tolerance in cattle. Breed effects for differing compositions of Brahman and Angus were also estimated. As Brahman breed composition increased by 25% undercoat length, topcoat length, body temperature under low THI conditions, and body temperature under high THI conditions decreased by 1.32 mm, 2.94 mm, 0.11 °C, and 0.14 °C, respectively. Under both low and high THI conditions, cattle with 25% Brahman breed composition or greater maintained a significantly lower body temperature than the 100% Angus breed group. The incorporation of Brahman germplasm is recommended for herds that often experience heat stress conditions in order to increase resilience to heat stress.

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