The effect of cooling vests on physiological and perceptual responses: a systematic review

Climate Change and Occupational Heat Strain Among Women Workers: A Systematic Review

Climate change increases heat stress exposure and occupational heat strain in tropical and subtropical regions with generally hot-humid climate conditions. The present systematic review was conducted to assess the effect of climate change on occupational heat strain among women workers. In this study, three main databases (PubMed, Scopus, and Web of Science) were searched to find relevant literature on climate change and its effects using subject headings and appropriate MeSh terms. This article has been written according to the PRISMA checklist. A total of 6,176 studies were identified for screening and 13 studies were eligible for data extraction. Scientific evidence reveals that there is an imprecise but positive relationship between climate change and occupational heat strain regarding women workers. Some complications associated with occupational heat strain among women workers include fatigue, discomfort, dehydration, reduced brain function, and loss of concentration. Climate change can lead to an increase in the occurrence of heat-related illnesses and the levels of injury risk. In addition, its adverse health effects on women workers are mentioned. This systematic study identifies key priorities for action to better characterize and understand how occupational heat strain among women workers may be associated with climate change events. Strong evidence indicates that climate change will continue to cause occupational heat strain among women workers. It is essential to implement preventive measures considering multidisciplinary strategies to reduce the adverse effects of climate change on women workers health in hot weather settings. This can limit the health risks and negative effects of climate change.

Mitigating heat effects in the workplace with a ventilation jacket: Simulations of the whole-body and local human thermophysiological response with a sweating thermal manikin in a warm-dry environment

Climate change is increasingly affecting human well-being and will inevitably impact on occupational sectors in terms of costs, productivity, workers' health and injuries. Among the cooling garment developed to reduce heat strain, the ventilation jacket could be considered for possible use in workplaces, as it is wearable without limiting the user's mobility and autonomy. In this study, simulations with a sweating manikin are carried out to investigate the effects of a short-sleeved ventilation jacket on human thermophysiological responses in a warm-dry scenario. Simulations were performed in a climatic chamber (air temperature = 30.1 °C; air velocity = 0.29 m/s; relative humidity = 30.0 %), considering two constant levels of metabolic rate M (M1 = 2.4 MET; M2 = 3.2 MET), a sequence of these two (Work), and three levels of fan velocities (lf = 0; lf=2; lf=4). The results revealed a more evident impact on the mean skin temperature (Tsk) compared to the rectal temperature (Tre), with significant decreases (compared to fan-off) at all M levels, for Tsk from the beginning and for Tre from the 61st minute. Skin temperatures of the torso zones decreased significantly (compared to fan-off) at all M levels, and a greater drop was registered for the Back. The fans at the highest level (lf=4) were significantly effective in improving whole-body and local thermal sensations when compared to fan-off, at all M levels. At the intermediate level (lf=2), the statistical significance varied with thermal zone, M and time interval considered. The results of the simulations also showed that the Lower Torso needs to be monitored at M2 level, as the drop in skin temperature could lead to local overcooling and thermal discomfort. Simulations showed the potential effectiveness of the ventilation jacket, but human trials are needed to verify its cooling power in real working conditions.

Effect of air blowing inside isolated hospital clothing on perceptual and physiological heat strain in laboratory conditions

Heat stress is one of the most common complaints of health care employees who wear isolation gowns to protect themselves from biological agents, particularly during the warmer seasons. This study was conducted in a climatic chamber to determine the influence of airflow within isolated hospital gowns on physiological-perceptual heat strain indices. The experiment was conducted in three trials: regular clothes (CON), an impenetrable gown without air blowing (GO), and a gown with air blowing (GO + FAN) at temperature conditions of 27 °C and 25% relative humidity (RH). During the trial, physiological-perceptual response data were recorded for a half-hour on a treadmill at a speed of km/hr and a slope of 0% activity at 5-min intervals. The ASHRAE Likert scale was used to assess thermal comfort (TC), thermal sensation (TS), and skin wetness sensation (WS). As the results show, there was a significant difference in mean scores for TC and WS in both sexes when working in the CON, GO, and GO + FAN groups (P < 0.001). In women, the mean scores for TS, TC, and WS reduced considerably (P < 0.001) in the GO and GO + FAN in the amount of 10 and 12 CFM (20 [Formula: see text]/h), but in males, there was a statistically significant difference between mean scores (P < 0.001) in the GO + FAN at 12 CFM (20 [Formula: see text]/h) and 14 CFM (24 [Formula: see text]/h). Also, the greatest difference between the average heart rate, chest temperature, and temperature inside the clothes in women and men in the trials GO and GO + FAN was observed in the air flow 12 CFM and 14 CFM, respectively (P < 0.001). The usage of an air blower in isolated hospital clothes has been shown to influence physiological-perceptual parameters in men and women substantially. The existence of airflow in these gowns can improve safety, performance, and thermal comfort while also decreasing the risk of heat-related disorders.

Effects of liquid cooling garment on physiological and psychological strain of firefighter in hot and warm environments

This study aimed to explore the effects of a liquid cooling garment on the physiological and psychological strains of firefighters. Twelve participants wearing firefighting protective equipment with the liquid cooling garment (LCG group) and without the liquid cooling garment (CON group) were recruited to conduct human trials in a climate chamber. During the trials, physiological parameters (mean skin temperature (T_sk), core temperature (T_c), and heart rate (HR)) and psychological parameters (thermal sensation vote (TSV), thermal comfort vote (TCV), and rating of perceived exertion (RPE)) were measured continuously. The heat storage, sweating loss, physiological strain index (PSI), and perceptual strain index (PeSI) were calculated. The results indicated that the liquid cooling garment decreased the mean skin temperature (maximum value of 0.62 °C), scapula skin temperature (maximum value of 1.90 °C), sweating loss (26%), and PSI (0.95 scales) with a significant difference (p < 0.05) at some time points when compared with the CON group. Moreover, the liquid cooling garment had little influence (p > 0.05) on core temperature, heart rate, TSV, TCV, RPE, and PeSI. The association analysis indicated that psychological strain had the potential to predict physiological heat strain with an R² value of 0.86 between the PeSI and PSI. This study offers insights into the evaluation of cooling system performance, the design of next-generation cooling systems, and the improvement of firefighters' benefits.

Thermal stress and TiO2 nanoparticle-induced oxidative DNA damage and apoptosis in mouse hippocampus

Titanium dioxide (nano-TiO₂) is used abundantly in various industrial products and novel medical therapies. In addition, the impact of climate change on the health and safety will undoubtedly increase in the future. However, the effects of exposure to these nanoparticles and heat stress on hippocampal DNA damage and apoptosis remain unclear. This study was conducted to evaluate the DNA damage and apoptosis in the hippocampal tissue and the physiological responses in mice induced by intraperitoneal (i.p.) administration of TiO₂ nanoparticles (NPs) and heat stress for 14 consecutive days. The results showed that heat stress and TiO₂-NPs were induced in the mouse hippocampus that led to hippocampal reactive oxygen species generation, oxidative damage of DNA, and apoptosis in a partly dose-dependent manner, especially at very hot temperature. High doses of nanosized TiO₂ and severe heat stress significantly damaged the function of the hippocampus, as shown in the comet assay and apoptosis tests. The results of this study may provide data for appropriate measures to control and assess the risk of nano-TiO₂ and thermal stress hazards to human health, especially workers. Safety guidelines and policies should be considered when handling nanomaterials in a hot environment.

Effect of heat stress on DNA damage: a systematic literature review

Thermal stress has a direct effect on various types of DNA damage, which depends on the stage of the cell cycle when the cell is exposed to different climate conditions. A literature review was conducted to systematically investigate and assess the overall effect of heat stress and DNA damage following heat exposure. In this study, electronic databases including PubMed, Scopus, and Web of Science were searched to find relevant literature on DNA damage in different ambient temperatures. Outcomes included (1) measurement of DNA damage in heat exposure, (2) three different quantification methods (comet assay, 8-hydroxy-2-deoxyguanosine (8-OHdG), and γ-H2AX), and (3) protocols used for moderate (31) and high temperatures (42). The evidence shows that long exposure and very high temperature can induce an increase in DNA damage through aggregate in natural proteins, ROS generation, cell death, and reproductive damage in hot-humid and hot-dry climate conditions. A substantial increase in DNA damage occurs following acute heat stress exposure, especially in tropical and subtropical climate conditions. The results of this systematic literature review showed a positive association between thermal stress exposure and inhibition of repair of DNA damage.