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Purpose: Healthcare workers (HCWs) wearing personal protective equipment (PPE) experience physiological strain that can impair motor and psychological functions, potentially affecting patient care. We assessed the effects of heat exposure on maximal strength and risk-taking behavior among PPE-wearing HCWs and the efficacy of ice slurry to alleviate adverse effects. Methods: Seventeen HCWS completed two experimental trials in a crossover design, consuming 5 g·kg−1 of body mass of ambient drink (AMB) or ice slurry (ICE) before donning PPE and undergoing 2 h of simulated decontamination exercise (wet-bulb globe temperature (WBGT): 25.9° C ± 0.8°C, PPE microenvironment WBGT: 29.1°C ± 2.1°C). Body core temperature (Tc), heart rate (HR), chest skin temperature (Tsk), ratings of perceived exertion (RPE), thermal sensation (RTS), maximal voluntary contraction (MVC), risk-taking behavior (balloon analogue risk-taking task (BART)), and salivary cortisol were assessed. Results: Predrinking to postdrinking ΔTc was greater in ICE (−0.2°C ± 0.1°C) than AMB (−0.0°C ± 0.1°C, P = 0.003). Post-drinking RTS was lower in ICE (2.7 ± 1.2) than AMB (4.1 ± 0.4, P < 0.001). ICE and AMB had similar Tc and HR (both P > 0.05), but Tsk was lower in ICE than AMB (P = 0.049). A lower MVC (30.3 ± 6.7 vs 27.4 ± 4.9 kg, P = 0.001) and higher BART-adjusted total pump count (472 ± 170 vs 615 ± 174 pumps, P = 0.017) was observed pretrial to posttrial in AMB but absent in ICE (both P > 0.05). Salivary cortisol was similar between trials (P = 0.42). Conclusions: Heat-exposed PPE-wearing HCWs had impaired maximal strength and elevated risk-taking behavior. This may increase the risk of avoidable workplace accidents that can jeopardize HCWs and patient care. Ice slurry ingestion alleviated these heat-related impairments, suggesting its potential as an ergogenic aid. [ABSTRACT FROM AUTHOR]

With climate change fueling more frequent and intense periods of hot weather, heat stress management programs are becoming increasingly important for protecting the health and safety of workers in the Canadian mining industry. While the inclusion of heat-mitigation measures such as those provided by the American College of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) are commonly employed by industry, there is a need to develop more comprehensive industry-specific measures for heat stress prevention and management. To better understand current heat management practices and identify opportunities for improvement, an exploratory survey of 51 employees responsible for health and safety at underground mining (n = 35), and surface operations (n = 16) (e.g., open-pit mining, milling, smelting, and exploration site) was conducted in Canada. The respondents answered 50 questions related to workplace heat stress management, including descriptors of the workplace environment, perceived heat stress hazard, administration of heat stress management programming, heat stress emergency procedures, environmental monitoring strategies, and knowledge of mining-specific regulations related to heat stress. Twenty-four managers (47%) reported that heat-related illnesses led to restricted duty or lost time claims at their site, with a median of 5 [IQR: 2–10, max: 30] reportable heat-related illnesses occurring per site annually. Many also felt that heat-related illnesses are under-reported by their workforce (n = 36, 71%). Most sites reported established heat stress management programs to prevent heat illness (n = 43, 84%), typically based on the TLVs (n = 38, 75%). Although some organizations do conduct pre-task evaluations for heat stress (n = 30, 59%), more than half do not conduct post-job evaluations (n = 28, 55%) or pre-employment screening for heat stress vulnerability (n = 3, 6%). While our findings indicate that the health and safety managers recognize the hazard posed by heat and have stated practices to help address the hazard, we also observed inconsistencies in heat stress management programming across the sample. Developing and adopting a standard heat stress management and reporting system would be an important step toward protecting workers from existing and emerging threats from extreme heat and climate change. [ABSTRACT FROM AUTHOR]

Objective: To explore the relationship between occupational heat exposure, physiological heat strain indicators and adverse outcomes in pregnant women. Design: Prospective cohort. Setting: Workplaces in Tamil Nadu, India. Sample: A cohort of 800 pregnant women engaged in moderate to heavy physical work in 2017–2019 and 2021–2022. Methods: Participants were recruited at between 8 and 14 weeks of gestation. Occupational heat exposure and heat strain indicators were captured each trimester. 'Heat exposed' was defined as heat stress exceeding the threshold limit value (TLV) for safe manual work (with maximum wet‐bulb globe temperatures of 27.5°C for a heavy workload and 28.0°C for a moderate workload). Physiological heat strain indicators (HSIs) such as core body temperature (CBT) and urine specific gravity (USG) were measured before and after each shift. Heat‐related health symptoms were captured using the modified HOTHAPS questionnaire. Main outcome measures: The main outcome measures included (1) a composite measure of any adverse pregnancy outcome (APO) during pregnancy (including miscarriage, preterm birth, low birthweight, stillbirth, intrauterine growth restriction and birth defects), (2) a composite measure of adverse outcomes at birth (3) and miscarriage. Results: Of the 800 participants, 47.3% had high occupational heat exposure. A rise in CBT was recorded in 17.4% of exposed workers, and 29.6% of workers experienced moderate dehydration (USG ≥ 1.020). Heat‐exposed women had a doubled risk of miscarriage (adjusted odds ratio, aOR 2.4; 95% confidence interval, 95% CI 1.0–5.7). High occupational heat exposure was associated with an increased risk of any adverse pregnancy and foetal outcome (aOR 2.3; 95% CI 1.4–3.8) and adverse outcome at birth (aOR 2.0; 95% CI 1.2–3.3). Conclusions: High occupational heat exposure is associated with HSIs and adverse pregnancy outcomes in India. [ABSTRACT FROM AUTHOR]

In order to obtain the new cellulose-degrading bacteria at normal temperature, a bacterial strain named as 18B with cellulosedegrading ability was isolated and purified from garden compost in this study. Congo red staining experiment and filter paper degradation experiment were conducted to verify its cellulose-degradation ability. 16S rRNA sequence alignment and whole genome alignment confirmed that it belonged to the genus Olivibacter, and was the closest to Olivibacter jilunii 14-2AT . Further comparative physiological and biochemical characterization revealed differences with O. jilunii 14-2AT in terms of growth temperature, oxidase and glycolysis. The strain 18B grew in the range of 12-48℃, and the optimal growth temperature was 30-37℃ . O. jilunii 14-2AT grew at 4-42℃ . Strain 18B was positive for oxidase and negative for glycolysis, while O. jilunii 14-2AT had no oxidase activity and was positive for glycolysis. Combined with the results of the genomewide covariance alignment, it was known that strain 18B had a certain evolutionary relationship with O. jilunii 14-2AT . The cellulose-degradation ability was found that the cellulase activity of 18B was up to 82.14+0.99 -9.90 U/L at 37℃, 200 r/min until the 5th d. Meanwhile, the enzyme activity could be maintained without degradation under the incubation conditions with sodium carboxymethyl cellulose as the only carbon source and only inorganic nitrogen source added. O. jilunii 14-2AT had no cellulose degrading ability and could not survive in a culture environment where sodium carboxymethylcellulose was the only organic carbon source. The results of whole genome sequencing showed that there were cellulase genes in the genome of strain 18B. The cellulase genes were heterologous expressed in Escherichia coli, and the degradation ability of the expressed products was tested. The results showed that the cellulase genes were active. The above results finally identified strain 18B as a new physiological strain of O. jilunii with cellulase activity. [ABSTRACT FROM AUTHOR]

Introduction: The metabolomic profiles of Soldiers entering the U.S. Special Forces Assessment and Selection course (SFAS) have not been evaluated. Objectives: To compare pre-SFAS blood metabolomes of Soldiers selected during SFAS versus those not selected, and explore the relationships between the metabolome, physical performance, and diet quality. Methods: Fasted blood samples and food frequency questionnaires were collected from 761 Soldiers prior to entering SFAS to assess metabolomic profiles and diet quality, respectively. Physical performance was assessed throughout SFAS. Results: Between-group differences (False Discovery Rate < 0.05) in 108 metabolites were detected. Selected candidates had higher levels of compounds within xenobiotic, pentose phosphate, and corticosteroid metabolic pathways, while non-selected candidates had higher levels of compounds potentially indicative of oxidative stress (i.e., sphingomyelins, acylcarnitines, glutathione, amino acids). Multiple compounds higher in non-selected versus selected candidates included: 1-carboxyethylphenylalanine; 4-hydroxy-nonenal-glutathione; α-hydroxyisocaproate; hexanoylcarnitine; sphingomyelin and were associated with lower diet quality and worse physical performance. Conclusion: Candidates selected during SFAS had higher pre-SFAS levels of circulating metabolites that were associated with resistance to oxidative stress, higher physical performance and higher diet quality. In contrast, non-selected candidates had higher levels of metabolites potentially indicating elevated oxidative stress. These findings indicate that Soldiers who were selected for continued Special Forces training enter the SFAS course with metabolites associated with healthier diets and better physical performance. Additionally, the non-selected candidates had higher levels of metabolites that may indicate elevated oxidative stress, which could result from poor nutrition, non-functional overreaching/overtraining, or incomplete recovery from previous physical activity. [ABSTRACT FROM AUTHOR]

Japanese collegiate and club lacrosse games are often held under environmental conditions of extreme heat in the summer. Lacrosse players are also required to wear protective equipment, which is a risk factor for heat-related illness. Nevertheless, the thermoregulatory responses of lacrosse players under such conditions are poorly understood. The present study compared the thermoregulatory responses in subjects wearing the mens’ lacrosse uniform or general athletic clothes during an exercise-simulated lacrosse match played in the heat (high temperatures). Eight men performed two experimental trials of 4 × 15-min intermittent cycling exercise in the heat (35°C, 50% relative humidity). All participants performed two trials wearing a lacrosse uniform (WEAR) or general athletic clothes (CON). The physiological strain index was significantly higher (p < 0.05) in the WEAR condition than in CON, and exceeded the high risk level for heat-related illness in WEAR during the 3rd quarter. Additionally, rectal temperature, skin temperature, heart rate, and ratings for perceived exertion, thermal sensation, and thermal comfort were significantly higher (p < 0.05) in the WEAR condition than in CON. Rectal temperature continued to increase during half-time in the WEAR condition, but not in CON (p < 0.05). These findings indicate that lacrosse players are at a higher risk of heat-related illness compared to other team sport athletes during a match because of the protective equipment worn, especially after half-time. Although further studies are required to confirm the thermoregulatory responses during an actual lacrosse match, our data will be useful in developing strategies to minimize the risk of heat-related illness.

Purpose: We compared the effectiveness of three field-based training programs, namely military-based heat acclimatization (MHA), isothermic conditioning (IC) and interval training (IT), in inducing physiological adaptations in tropical natives. Methods: Fifty-one untrained tropical native males (mean ± standard deviation: age, 25 ± 2 yr; body mass index, 23.6 ± 3.2 kg·m−2; body fat, 19% ± 5%; 2.4-km run time, 13.2 ± 0.9 min) donned the Full Battle Order attire (22 kg) and performed a treadmill route march heat stress test in an environmental chamber (dry bulb temperature, 29.9°C ± 0.5°C; relative humidity, 70% ± 3%). Heat stress tests were conducted before (PRE) and after (POST) a 2-wk training intervention consisting of either a MHA (n = 17, 10 sessions of military-based heat acclimatization), IC (n = 17, 10 sessions with target gastrointestinal temperature (T gi) ≥ 38.5°C) or IT (n = 17, six sessions of high-intensity interval training) program. T gi, HR, mean weighted skin temperature (T sk), physiological strain index (PSI) and thigh-predicted sweat sodium concentration ([Na+]) were measured and analyzed by one-factor and two-factor mixed design ANOVA with a 0.05 level of significance. Results: Field-based IC induced a greater thermal stimulus than MHA (P = 0.029) and IT (P < 0.001) during training. Reductions in mean exercise T gi (−0.2°C [−0.3°C, 0.0°C]; P = 0.009), PSI (−0.4 [−0.7, −0.1]; P = 0.015) and thigh-predicted sweat [Na+] (−9 [−13, −5 mmol·L−1]; P < 0.001) were observed in IC but not MHA and IT (all P > 0.05). Resting HR (MHA, −4 bpm [−7, 0 bpm]; P = 0.025; IC, −7 bpm [−10, −4 bpm]; P < 0.001; IT, −4 bpm [−8, −1 bpm]; P = 0.008) and mean exercise HR (MHA, −4 [−8, 0 bpm]; P = 0.034; IC, −11 bpm [−15, −8 bpm]; P < 0.001, IT = −5 bpm [−9, −1 bpm]; P = 0.012) were lowered in all groups after training. Isothermic conditioning elicited a greater attenuation in mean exercise HR and thigh-predicted sweat [Na+] relative to MHA (both P < 0.05). No between-group differences were observed when comparing MHA and IT (all P > 0.05). Conclusions: Isothermic conditioning induced a more complete heat-adapted phenotype relative to MHA and IT. Interval training may serve as a time efficient alternative to MHA. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effects of stab-resistant body armor (SRBA) on the physiological and psychophysical strain of security guards. Ten volunteers performed a 50-min treadmill walk at 7.0 km/h in a climate chamber where the ambient temperature and relative humidity were controlled to 40 °C and 40%, respectively. All the participants performed the walk under two experimental conditions: wearing a uniform without (CON) and with armor (SRBA). Several physiological responses (core temperature, skin temperature, heart rate, and oxygen consumption) and psychophysical parameters (thermal sensation vote, thermal comfort vote, ratings of perceived exertion, and clothing and skin wetness) were recorded during the trials. Furthermore, the sweat loss, body heat storage, and physiological strain index (PSI) were calculated based on the measurements. The results indicated no significant difference between the SRBA and CON groups in terms of core temperature, mean skin temperature, heart rate, oxygen consumption, body heat storage, or PSI over time. However, a significant difference (p < 0.05) between the two trials was observed in terms of scapula skin temperature (40 and 45 min) and body temperature (0 and 45 min). Moreover, the SRBA (3.5 kg and 17% body area coverage) caused an 11% increase in sweat loss, but a 27% reduction in sweating efficiency. Although the armor caused slight discomfort, wetness, and exertion, no significant difference between the two trials was observed in terms of the psychophysical responses. Therefore, the SRBA imposed negligible physiological and psychophysical strain during the 50-min walk in this case. [ABSTRACT FROM AUTHOR]

Abstract This study investigated the effects of weight increase of firefighters’ boots on physiological and psychological strain. Seven young males (70.9 ± 4.8 kg in body mass, BM) participated in the following four boot conditions while wearing standard firefighting personal protective equipment: 3.2, 3.9, 4.6, and 5.3 kg (4.5, 5.5, 6.5, and 7.5%BM). The results showed that the four boot conditions resulted in no differences in rectal temperature, mean skin temperature, energy expenditure and overall thermal comfort during walking, while increments in heart rate were greater for 5.3 kg than for other three conditions (P

Background: Evidence regarding heat stress, dehydration, hypohydration and fluid balance effects on semi-professional athletes' cognitive function is still limited. This study aimed to examine the effects of exercise heat-stress, hyperthermia, dehydration and fatigue on cognitive performances in semi-professional athletes. Methods: Eighteen healthy male athletes from individual and team sports participated. Participants completed a cognitive and mood test battery prior, immediately after and post 120 min of treadmill exercise. A soccer-specific intermittent treadmill exercise protocol was completed in four experimental trials in temperate (normothermic) and hot (hyperthermic) conditions. Participants were hydrated and dehydrated in both conditions. Trial conditions were; normothermic 16.4 ± 0.02°C and 52 ± 1% RH, while hyperthermic 33.9 ± 0.3°C and 61 ± 1% RH. Results: Response times; the Stroop effect and Visual search tasks were quicker (584 to 690 ms, p= 0.001; 1978 to 2213 ms, p= 0.003) in the heat. Cognitive tasks showed that reaction time, visual process, motor speed and mood were similar in normothermic (p=0.001). Accuracy improved in hydrated hyperthermic by 1.2% (p=0.002) in Visual search. Total Mood Disturbance was significant in heat (p<0.001). Hydration status had no major effect in some cognition performance markers except for mood. Conclusion: The response times and accuracy improved following the cognitive testing in semi-professional athletes exercising in relatively humid, hot conditions. However, semi-professional athletes' cognitive performances were relatively affected by hypohydration and their hydration status needs to be closely monitored during exercise. [ABSTRACT FROM AUTHOR]

Tree pruning is integral to sawtimber production in South Africa, the main purpose being the production of knot-free wood and access for fire protection. Although handheld pruning tools have been used for decades, motor-manual tools have recently been introduced. However, knowledge of possible ergonomic risks and possible productivity associated with either pruning method is limited in the literature. Hence the objective of this study was to assess human workload associated with, and possible productivity gains of, motor-manual pruning against manual operations in 2.0 m and 3.5 m pruning lifts in Pinus patula stands. The study was completed in two stands in the KwaZulu-Natal Midlands of South Africa. Information collected included time study and heart rate data. Time study results showed that motor-manual operations were more productive than manual operations in both the 2.0 m and 3.5 m pruning lifts. Pruning operations fall under the "medium to heavy" workload classification. These results show promise as the first steps in investigating the effect of manual and motor-manual operations on productivity and workload of pruning operations in South Africa. However, it is recommended for this study to be repeated with gender, terrain conditions, temperature, and musculoskeletal efforts as additional factors to workload and productivity. [ABSTRACT FROM AUTHOR]

Background There are differences between dry and wet sauna baths because of the heat load and human body’s reactions. High humidity in a wet sauna makes evaporation of sweat from the skin surface more difficult. In addition, the dynamics of sweating is different in men and women. The aim of the study was to assess changes in physiological indicators and to compare the impact of dry and wet saunas on the thermal comfort feeling, which was assessed using the Bedford thermal scale, and the physiological strain index (PSI) and the cumulative heat stress index (CHSI) in young healthy women. Material and Methods Ten women aged 22−24 years took part in the study. A session in each sauna lasted 60 min and consisted of 3 thermal 15-min exposures, in 5-min intervals for rest and cooling with water. The temperature in the dry sauna was 91±1.2°C and in the wet sauna 59±1.3°C, while the humidity was 18±0.7% and 60.5±0.8%, respectively. Body weight, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), rectal temperature (T re ) and the thermal sensation (Bedford scale) were also measured. The PSI and CHSI values were both calculated. Results The average weight loss after a dry sauna bath was significantly higher than after a wet sauna bath. Significantly higher increases in T re , as well as in HR were observed after treatment in the wet sauna, compared to the dry sauna. Both treatments resulted in an increase in SBP and a decrease in DBP. The arduousness of thermal discomfort and the levels of PSI and CHSI were skurgreater in the wet sauna bathing than in the dry sauna. Conclusions Heat exposure in the wet sauna creates a greater burden for young women’s bodies than the same dry sauna treatment, and the changes observed in the examined traits were higher than in men subjected to similar thermal loads. Med Pr. 2019;70(6):701–10

Purpose: To examine the effect of a hot humid (HH) compared with a hot dry (HD) environment, matched for heat stress, on intermittent-sprint performance. In comparison with HD, HH environments compromise evaporative heat loss and decrease exercise tolerance. It was hypothesized that HH would produce greater physiological strain and reduce intermittent-sprint exercise performance compared with HD. Method: Eleven male team-sport players completed the cycling intermittent-sprint protocol (CISP) in 3 conditions, temperate (TEMP; 21.2°C ± 1.3°C, 48.6% ± 8.4% relative humidity [rh]), HH (33.7°C ± 0.5°C, 78.2% ± 2.3% rh), and HD (40.2°C ± 0.2°C, 33.1% ± 4.9% rh), with both heat conditions matched for heat stress. Results: All participants completed the CISP in TEMP, but 3 failed to completed the full protocol of 20 sprints in HH and HD. Peak power output declined in all conditions (P < .05) but was not different between any condition (sprints 1-14 [N = 11]: HH 1073 ± 150 W, HD 1104 ± 127 W, TEMP, 1074 ± 134; sprints 15-20 [N = 8]: HH 954 ± 114 W, HD 997 ± 115 W, TEMP 993 ± 94; P > .05). Physiological strain was not significantly different in HH compared with HD, but HH was higher than TEMP (P < .05). Conclusion: Intermittent-sprint exercise performance of 40 min duration is impaired, but it is not different in HH and HD environments matched for heat stress despite evidence of a trend toward greater physiological strain in an HH environment. [ABSTRACT FROM AUTHOR]

While stress has been an important research area in the field of ergonomics, research on social stress and on the combination of stressors is largely lacking. This study examined the effects of social stress on psychological and physiological strain and performance. As an exploratory research question we looked at the combined effects of social stress and noise. Fifty-one male student participants were tested for 2 h using a computer-based simulation of a process control environment with multiple tasks. Social stress (TSST) and noise (80 dB) were varied experimentally. During the task, we repeatedly measured primary and secondary task performance, subjective strain, and psychophysiological strain (cortisol, heart rate). We found a main effect of social stress on physiological strain, both on cortisol and heart rate, but no main effects of social stress on subjective strain and performance. These results suggest that maintaining performance under stress comes at the cost of physiological strain. Practitioner summary: Although the presence of social stress is common at work, little experimental work has been done. Our experiment provides empirical evidence for negative effects of social stress on physiological stress responses while subjective strain and performance decrements could not be detected. Abbreviations: ANOVA: analysis of variance; b/min: beats per minute; CAMS: cabin air management system; CO2: carbon dioxide; dB: decibel; Df: degrees of freedom; ECG: electrocardiography; h: hours; Hz: hertz; M: mean; min: minutes; N: sample size; nmol/l: nanomol per liter; O2: oxygen; pm: post meridiem; SD: standard deviation; SE: standard error; sec/s: seconds; TSST: trier social stress test [ABSTRACT FROM AUTHOR]

We report on the development of a new model of alveolar air–tissue interface on a chip. The model consists of an array of suspended hexagonal monolayers of gelatin nanofibers supported by microframes and a microfluidic device for the patch integration. The suspended monolayers are deformed to a central displacement of 40–80 µm at the air–liquid interface by application of air pressure in the range of 200–1,000 Pa. With respect to the diameter of the monolayers, that is, 500 µm, this displacement corresponds to a linear strain of 2–10% in agreement with the physiological strain range in the lung alveoli. The culture of A549 cells on the monolayers for an incubation time of 1–3 days showed viability in the model. We exerted a periodic strain of 5% at a frequency of 0.2 Hz for 1 hr to the cells. We found that the cells were strongly coupled to the nanofibers, but the strain reduced the coupling and induced remodeling of the actin cytoskeleton, which led to a better tissue formation. Our model can serve as a versatile tool in lung investigations such as in inhalation toxicology and therapy. [ABSTRACT FROM AUTHOR]

This study investigated the effects of weight increase of firefighters' boots on physiological and psychological strain. Seven young males (70.9 ± 4.8 kg in body mass, BM) participated in the following four boot conditions while wearing standard firefighting personal protective equipment: 3.2, 3.9, 4.6, and 5.3 kg (4.5, 5.5, 6.5, and 7.5%BM). The results showed that the four boot conditions resulted in no differences in rectal temperature, mean skin temperature, energy expenditure and overall thermal comfort during walking, while increments in heart rate were greater for 5.3 kg than for other three conditions (P < 0.05). Subjects felt less warm and had less uncomfortable feet during exercise for the 3.2 kg condition compared to the three other heavier conditions (P < 0.05). These results indicate that psychological strain due to the load carried on the feet appeared earlier (between 4.5 to 5.5%BM) than physiological strain in terms of heart rate (between 6.5 to 7.5%BM). We finally suggest a 5% body mass upper limit for boot weight because subjective strain of the feet may be a valuable preliminary alarm for the physiological strain of firefighters wearing heavy boots. [ABSTRACT FROM AUTHOR]

This cross-sectional study aimed to assess the physiological response of physical therapists to compare the physiological workload within three groups of varying work experience and their comparative physiological responses during a 15-min recovery period. Thirty therapists participated in the present study. They were divided into three groups with varying levels of work experience based on the number of years they had been in active employment: 1) Early Career (EC) group = 2–6 years); 2) Mid-Career (MC) group = 7–11 years), and 3) Late career (LC) group = over 11 years). Each group included 10 subjects comprised of both males and females. To conduct the measurements, each therapist treated one hemiplegic patient for 20 min using a passive range of motion protocol and then rested for 15 min. The maximum voluntary contraction on trapezius and deltoid muscles were tested using electromyography before and after treatment. During treatment, the muscle workload, muscle fatigue, and cardiovascular load were measured. The perceived workload was assessed using a subjective workload index (SWI) questionnaire following treatment. The three work experience groups of physical therapists performed a similar workload. The SWI corresponded well with physiological measurement. The muscle capacity after treatment of the EC group was significantly lower than that of the MC group (p < 0.05). Notably, the right deltoid of the LC group was significantly lower than that of the MC group. The physical therapists worked with a moderate, objectified workload. A 15-min rest period brought the cardiovascular load below 30% and lowered fatigue in the right deltoids. This result may indicate a musculoskeletal disorder warning signal for the physical therapists. [ABSTRACT FROM AUTHOR]

Occupational heat stress apart from adverse heat-related health consequences also induces DNA damage in workers exposed to high working temperatures. We investigated the association between chronic heat exposures and Micronuclei (MN) frequency in lymphocytes of 120 workers employed in the steel industry. There was a significant increase in the MN-frequency in exposed workers compared to the unexposed workers (X2 = 47.1; p < 0.0001). While exposed workers had higher risk of DNA damage (Adj. OR = 23.3, 95% CI 8.0–70.8) compared to the unexposed workers, among the exposed workers, the odds of DNA damage was much higher for the workers exposed to high-heat levels (Adj. OR = 81.4; 95% CI 21.3–310.1) even after adjusting for confounders. For exposed workers, years of exposure to heat also had a significant association with higher induction of MN (Adj. OR = 29.7; 95% CI 2.8–315.5). Exposures to chronic heat stress is a significant occupational health risk including damages in sub-cellular level, for workers. Developing protective interventions to reduce heat exposures is imperative in the rising temperature scenario to protect millions of workers across the globe. [ABSTRACT FROM AUTHOR]

Introduction: Workers in open pit iron ore mines are exposed to heat stress which can cause health and safety problems. The purpose of this study was to evaluate heat stress among open-pit mine workers of iron ore based on Wet Bulb Globe Temperature (WBGT) index and also to investigate its relationship with physiological Strain. Material and Method: This cross-sectional study was conducted on 120 healthy miners, working in an open-pit mine, during summer season, in 2014. Physiological parameters, including core body temperatures and heart rate, were measured according to ISO 9886 standard and physiological strain indices, including Physiological Strain Index (PSI) and Physiological Strain Index based on Heart Rate (PSIHR), were calculated using the equation. Environmental variables as well as physiological parameters were simultaneously measured and recorded during work shift. WBGT index was calculated according to ISO 7243 and using the equation. Statistical analysis was performed using the SPSS software version 22. Result: The mean WBGT index was estimated 29.09oC for workers. “Drilling” and “factory and Krasher” units showed the highest and lowest WBGT index values of 31.06oC and 29.05oC, respectively. Workers occupational exposure to heat stress were higher than recommended thresholds based on WBGT index in all work units. A statistically significant correlation was found between WBGT index and physiological strain indices (P value

Objectives: The objectives of these investigations completed on workplaces in the Hungarian mining industry were to characterize the physiological strain of workers by means of work pulse and to examine the effects of work-related psychological factors. Material and Methods: Continuous heart rate (HR) recording was completed on 71 miners over a total of 794 shifts between 1987 and 1992 in mining plants of the Hungarian mining industry using a 6-channel recorder – Bioport (ZAK, Germany). The work processes were simultaneously documented by video recording along with drawing up the traditional ergonomic workday schedule. All workers passed health evaluation for fitness for work. The effects of different psychological factors (simulated danger, “instrument stress,” presence of managers, and effect of prior involvement in accidents as well as different mining technologies and work place illumination) on the work pulse were evaluated. The statistical analysis was completed using SPSS software (version 13.0, SPSS Inc., USA). Results: The work-related physiological strain differed between work places with different mining technologies in groups of 12–18 workers. The work pulse was lowest in bauxite mining (ΔHR = 22±8.9 bpm) and highest in drift drilling in dead rock with electric drilling machine (ΔHR = 30±6.9 bpm). During sham alarm situation the work pulse was significantly higher than during normal activities with the same physical task (ΔHR = 36.7±4.8 bpm vs. 25.8±1.6 bpm, p < 0.001). When work was performed under different psychological stress, the work pulse was consistently higher, while improving the work place illumination decreased the physiological strain appreciably (ΔHR (median, 25–75 percentiles) = 23, 20–26 bmp vs. 28, 25–31.3 bpm, p < 0.001). Conclusions: Recording the heart rate during whole-shift work along with the work conditions gives reliable results and helps isolating factors that contribute to increased strain. The results can be used to implement preventive and health promotion measures.

Background: Nurses are among high-risk occupational groups during the outbreak of epidemics. Therefore, these people are required to use personal protective equipment (PPE). Previous studies have shown that the use of personal protective equipment can affect people's thermal strain and mental workload., Objective: The present study was conducted with the aim of objectively and subjectively evaluating the use of protective clothing on the thermal strain and mental workload of nurses during the covid-19 pandemic., Methods: This cross-sectional study was divided into two groups with a sample size of 300 people who were selected by systematic random method. In the first group, 120 people were objectively evaluated (use of protective clothing). In the second group, 180 people only completed the questionnaire of mental workload, feeling of heat and sweating and other information related to the type of clothing and the duration of its use, etc. Measurements were done in August and September of 2021 and in the morning shift of hospitals. Data were analyzed using SPSS version 21 software and chi-square, independent T-test and linear regression tests., Results: The average age and average working hours per month of the participants in the study were 33.51±7.88 years, 187.91±35.37 hours, respectively. The results showed that the predicted average vote (PMV) index and the predicted percentage of dissatisfied (PPD), moisture felt on the skin surface, the feeling of desirability and pleasantness of the temperature, the weight of sweat and the humidity inside the clothes between the two groups of people using insulated clothes There is a significant difference between medicine and dressing (P < 0.05). There was a significant relationship between mental workload and type of clothing, average working hours per month., Conclusions: The use of medical isolation clothes causes a high heat load on nurses and can increase their mental workload. On the other hand, people using normal gowns suffer from a high mental workload due to the fear of disease due to the uncertainty of high-level protection. In addition, medical isolation clothes increase the humidity of the skin due to their impermeability, which causes skin complications.

Fire service instructors (FSI) regularly experience different types of fire exercises, however the strain experienced from these scenarios is not well understood. This study aims to identify the physiological and perceptual strain of Fire Service Instructors (FSI) to three training exercises: DEMO, ATTACK, COMPARTMENT, and the different roles performed: SETTER, INSTRUCTOR. The study also aims to assess the effect that different exercise patterns over a day (BOX, MULTI, COMBINATION) have on immunological responses. Sixteen FSI (age: 41 ± 8 years, body mass: 83.7 ± 6.7 kg, height: 177.0 ± 6.7 cm) were recruited, with 10 FSI completing the three exercises. Physiological and perceptual measures were collected prior to and immediately post each exercise. Venous blood samples were collected at the beginning and end of each day. One-way analysis of variance (ANOVA) were conducted to assess differences in physiological variables between exercise types, independent samples t-tests were conducted between roles. Day changes in hematological variables were assessed by paired sample t-tests and analyzed by one-way ANOVAs to identify differences between exercise patterns. The COMPARTMENT exercise resulted in a greater change in rectal temperature (ΔTre) (0.49 ± 0.28 °C) than both the DEMO (0.23 ± 0.19 °C, p = 0.045) and ATTACK (0.27 ± 0.22 °C, p = 0.016). Within the COMPARTMENT exercise, the SETTER resulted in a greater ΔTre and rating of perceived exertion than the INSTRUCTOR (0.67 ± 0.29 °C vs. 0.43 ± 0.18 °C, p = 0.027 and 14 ± 2 vs. 11 ± 2, p = 0.001, respectively). Following a day of fire exercises white blood cells (WBC), neutrophils, lymphocytes (LYMPH), monocytes (MONO), platelets (PLT), mean platelet volume (MPV), Interleukin (IL)-6, and cardiac troponin T (cTnT) all increased (p < 0.05). Exercise patterns containing a COMPARTMENT exercise resulted in greater PLT, MPV, and IL-6. Total daily variation in ΔTre was correlated with postexercise WBC, MONO, and LYMPH. COMPARTMENT exercises produce the greatest physiological strain, with the SETTER role within this exercise causing the greatest ΔTre. Although predominately physiological responses remain within safe limits. Exercise patterns that include a COMPARTMENT exercise also generate a greater inflammatory response. [ABSTRACT FROM AUTHOR]

The aim of this experiment was to quantify physiological and perceptual responses to exercise with and without restrictive heat loss attire in hot and temperate conditions. Ten moderately-trained individuals (mass; 69.44±7.50 kg, body fat; 19.7±7.6%) cycled for 30-mins (15-mins at 2 W.kg-1 then 15-mins at 1 W.kg-1) under four experimental conditions; temperate (TEMP, 22°C/45%), hot (HOT, 45°C/20%) and, temperate (TEMPSUIT, 22°C/45%) and hot (HOTSUIT, 45°C/20%) whilst wearing an upper-body "sauna SUIT". Core temperature changes were higher (P<0.05) in TEMPSUIT (+1.7±0.4°C.hr-1), HOT (+1.9±0.5°C. hr-1) and HOTSUIT (+2.3±0.5°C.hr-1) than TEMP (+1.3±0.3°C.hr-1). Skin temperature was higher (P<0.05) in HOT (36.53±0.93°C) and HOTSUIT (37.68±0.68°C) than TEMP (33.50±1.77°C) and TEMPSUIT (33.41±0.70°C). Sweat rate was greater (P<0.05) in TEMPSUIT (0.89±0.24 L.hr-1), HOT (1.14±0.48 L.hr-1) and HOTSUIT (1.51±0.52 L.hr-1) than TEMP (0.56±0.27 L.hr-1). Peak heart rate was higher (P<0.05) in TEMPSUIT (155±23 b.min-1), HOT (163±18 b.min-1) and HOTSUIT (171±18 b. min-1) than TEMP (151±20 b.min-1). Thermal sensation and perceived exertion were greater (P<0.05) in TEMPSUIT (5.8±0.5 and 14±1), HOT (6.4±0.5 and 15±1) and HOTSUIT (7.1±0.5 and 16±1) than TEMP (5.3±0.5 and 14±1). Exercising in an upper-body sauna suit within temperate conditions induces a greater physiological strain and evokes larger sweat losses compared to exercising in the same conditions, without restricting heat loss. In hot conditions, wearing a sauna suit increases physiological and perceptual strain further, which may accelerate the stimuli for heat adaptation and improve HA efficiency. [ABSTRACT FROM AUTHOR]

The present study was conducted in order to evaluate efficiency of a personal body cooling system based on passive evaporative technologies and its effects on test subjects psycho-physiological suitability during exertional heat stress in hot environment. Performed results are based on conducted tests in climatic chamber in the Military Medical Academy Institute of Hygiene in Belgrade. Ten male test subjects were subjected to exertional heat stress test consisted of walking on motorized treadmill at a speed of 5 km/h in hot environment. Tests were performed with and without cooling system. As a physiological strain indicator the following parameters have been determined: mean skin temperature, tympanic temperature, heart rate and sweat rate. Results confirmed that cooling vest worn over the clothes was able to attenuate the physiological strain levels during exercise, when compared to identical exposure without the cooling system.

Bed pushing during patient transfer is one of the most physically demanding and yet common tasks in the hospital setting. Powered bed movers have been increasingly introduced to hospitals to reduce physiological strains on the users. This study introduces and quantifies the manpower efficiency and health benefits of a novel robotic-assisted omni-directional hospital bed transporter (SESTO Bed Mover) in comparison with a conventional manual transport stretcher (Stryker Trauma Stretcher 1037) and a powered transport stretcher (HOSPIMEK HMPT 740), which has a fifth powered wheel providing power assistance only in the forward direction. A total of 14 subjects were recruited (7 porters and 7 students) and were tasked to complete a course within a controlled lab environment. It is concluded that the robotic bed mover is able to halve the required manpower to push hospital beds as compared to conventional bed pushing without any additional physiological strain, potentially improving efficiency by two-fold. Electromyography (EMG) patterns showed that users relied on the shoulder and back muscles in a fashion similar to conventional pushing, further confirming the intuitive drive of the robotic bed mover. Overall, the robotic bed mover shows reduced physical demands, less manpower required for patient transport and reduced back muscle activities, which strongly suggest health benefits for workers in the hospital. [ABSTRACT FROM AUTHOR]

Background: Presumed effects of global warming on occupational heat stress aggravate conditions in many parts of the world, in particular in developing countries. In order to assess and evaluate conditions, heat stress must be described and measured correctly. Objective: Assessment of heat stress using internationally recognized methods. Design: Two such methods are wet bulb globe temperature (WBGT; ISO 7243) and predicted heat strain (PHS; ISO 7933). Both methods measure relevant climatic factors and provide recommendations for limit values in terms of time when heat stress becomes imminent. The WBGT as a heat stress index is empirical and widely recognized. It requires, however, special sensors for the climatic factors that can introduce significant measurement errors if prescriptions in ISO 7243 are not followed. The PHS (ISO 7933) is based on climatic factors that can easily be measured with traditional instruments. It evaluates the conditions for heat balance in a more rational way and it applies equally to all combinations of climates. Results: Analyzing similar climatic conditions with WBGT and PHS indicates that WBGT provides a more conservative assessment philosophy that allows much shorter working time than predicted with PHS. Conclusions: PHS prediction of physiological strain appears to fit better with published data from warm countries. Both methods should be used and validated more extensively worldwide in order to give reliable and accurate information about the actual heat stress.

This study aimed at examining physiological responses (i.e., oxygen uptake [VO2] and heart rate [HR]) to a semi-contact 3 × 3-min format, amateur boxing combat simulation in elite level male boxers. Eleven boxers aged 21.4 ± 2.1 years (body height 173.4 ± 3.7, body mass 74.9 ± 8.6 kg, body fat 12.1 ± 1.9, training experience 5.7 ± 1.3 years) volunteered to participate in this study. They performed a maximal graded aerobic test on a motor-driven treadmill to determine maximum oxygen uptake (VO2max), oxygen uptake (VO2AT) and heart rate (HRAT) at the anaerobic threshold, and maximal heart rate (HRmax). Additionally, VO2 and peak HR (HRpeak) were recorded following each boxing round. Results showed no significant differences between VO2max values derived from the treadmill running test and VO2 outcomes of the simulated boxing contest (p > 0.05, d = 0.02 to 0.39). However, HRmax and HRpeak recorded from the treadmill running test and the simulated amateur boxing contest, respectively, displayed significant differences regardless of the boxing round (p < 0.01, d = 1.60 to 3.00). In terms of VO2 outcomes during the simulated contest, no significant between-round differences were observed (p = 0.19, d = 0.17 to 0.73). Irrespective of the boxing round, the recorded VO2 was >90% of the VO2max. Likewise, HRpeak observed across the three boxing rounds were ≥90% of the HRmax. In summary, the simulated 3 × 3-min amateur boxing contest is highly demanding from a physiological standpoint. Thus, coaches are advised to systematically monitor internal training load for instance through rating of perceived exertion to optimize training-related adaptations and to prevent boxers from overreaching and/or overtraining.

Introduction: High workplace/ambient temperatures have been associated with Adverse Pregnancy Outcomes (APO). Millions of women working in developing nations suffer due to the rising temperatures caused by climate change. There are few pieces of research linking occupational heat stress to APO, and fresh evidence is required., Methodology: We used databases including PubMed, Google Scholar, and Science Direct to search for research on high ambient/workplace temperatures and their effects. Original articles, newsletters, and book chapters were examined. The literature we analysed was categorised as follows: Heat, strain, and physical activity harming both mother and fetus. After categorising the literature, it was examined to identify the major results., Results: We found a definite association between heat stress and APOs such as miscarriages, premature birth, stillbirth, low birthweight, and congenital abnormalities in 23 research articles. Our work provides important information for future research into the biological mechanisms that create APOs and various prevention measures., Conclusion: Our data suggest that temperature has long-term and short-term effects on maternal and fetal health. Though small in number, this study stressed the need for bigger cohort studies in tropical developing countries to create evidence for coordinated policies to safeguard pregnant women., (© 2023 Shanmugam Rekha et al., published by Sciendo.)

Personal cooling garments (PCGs) have gained increased attention in recent years due to heat stress and strain in the working environment. The present study was conducted in hot environments of an iron foundry to evaluate the efficacy of a battery-operated PCG. Twenty-four workers were exposed to climatic conditions of 35.89±1.25 °C, 35% relative humidity during 90-min work with PCG and habitual clothing (HC). Mean weighted skin temperature was significantly lower by 4.84±1.05 °C compared with HC 0.38±1.02 °C (p <0.05). A statistically significant difference was also observed for 0.492±0.26 g mean sweat loss in the PCG group compared with 0.775±0.42 g in the HC group (p <0.05). Heart rate, and back and chest skin temperatures were comparatively more reduced in the PCG group compared with the HC group. PCG provides a practical and economical way of alleviating the physiological effects of heat stress when environmental control is not feasible. [ABSTRACT FROM AUTHOR]

Objectives: The objectives of these investigations completed on workplaces in the Hungarian mining industry were to characterize the physiological strain of workers by means of work pulse and to examine the effects of work-related psychological factors.Material and Methods: Continuous heart rate (HR) recording was completed on 71 miners over a total of 794 shifts between 1987 and 1992 in mining plants of the Hungarian mining industry using a 6-channel recorder - Bioport (ZAK, Germany). The work processes were simultaneously documented by video recording along with drawing up the traditional ergonomic workday schedule. All workers passed health evaluation for fitness for work. The effects of different psychological factors (simulated danger, "instrument stress," presence of managers, and effect of prior involvement in accidents as well as different mining technologies and work place illumination) on the work pulse were evaluated. The statistical analysis was completed using SPSS software (version 13.0, SPSS Inc., USA).Results: The work-related physiological strain differed between work places with different mining technologies in groups of 12-18 workers. The work pulse was lowest in bauxite mining (ΔHR = 22±8.9 bpm) and highest in drift drilling in dead rock with electric drilling machine (ΔHR = 30±6.9 bpm). During sham alarm situation the work pulse was significantly higher than during normal activities with the same physical task (ΔHR = 36.7±4.8 bpm vs. 25.8±1.6 bpm, p < 0.001). When work was performed under different psychological stress, the work pulse was consistently higher, while improving the work place illumination decreased the physiological strain appreciably (ΔHR (median, 25-75 percentiles) = 23, 20-26 bmp vs. 28, 25-31.3 bpm, p < 0.001).Conclusions: Recording the heart rate during whole-shift work along with the work conditions gives reliable results and helps isolating factors that contribute to increased strain. The results can be used to implement preventive and health promotion measures. [ABSTRACT FROM AUTHOR]

BACKGROUND: Since a growing body of evidence points to mean training intensity over a season as a key factor to performance improvements, and there is wide evidence of the benefits of high-intensity intermittent training (HIIT) for endurance athletes, coaches need further information about the acute impact of typical HIIT workouts on endurance runners. OBJECTIVE: To compare the physiological strain and muscular performance parameters of endurance runners during two HIIT workouts by determining whether a typical HIIT for endurance runners (10 × 400 m) leads to a similar impact as a HIIT protocol (40 × 100 m) that increases the average training pace despite maintaining the same training volume. METHODS: Eighteen endurance runners performed 2 HIITs. Metabolic (blood lactate [BLa], blood ammonia [BAmm]), neuromuscular (countermovement jump [CMJ], handgrip strength test [HS]), and physiological responses were monitored during both protocols. RESULTS: No significant differences between HIITs were found for BLa_1 min post-test, BAmm, HS and HRpeak. Significant differences were found in fatigue-induced changes in CMJ performance (-0.36 cm in 40 × 100 m; +1.48 cm in 10 × 400 m), and in average pace (P <0.001) which was faster during the 40 × 100 m. CONCLUSIONS: Despite similar physiological, metabolic, and HS responses, the 40 × 100 m protocol allowed runners to train at a higher intensity, which might have important effects on the training prescription for endurance runners. [ABSTRACT FROM AUTHOR]

The study evaluated differences in response to exercise stress between endurance and high-intensity intermittent trained athletes in a thermoneutral environment using a physiological strain index (PSI). Thirty-two subjects participated in a running exercise under normal (23°C, 50% RH) conditions. The group included nine endurance trained athletes (middle-distance runners - MD), twelve high-intensity intermittent trained athletes (soccer players - HIIT) and eleven students who constituted a control group. The exercise started at a speed of 4 km.h-1 which was increased every 3 min by 2 km.h-1 to volitional exhaustion. The heart rate was recorded with a heart rate monitor and aural canal temperature was measured using an aural canal temperature probe. The physiological strain index (PSI) and the contribution of the circulatory and thermal components to the overall physiological strain were calculated from the heart rate and aural canal temperature. The physiological strain index differed between the study and control participants, but not between the MD and HIIT groups. The physiological strain in response to exercise stress in a thermoneutral environment was mainly determined based on the circulatory strain (MD group - 73%, HIIT group - 70%). The contribution of the circulatory and thermal components to the physiological strain did not differ significantly between the trained groups (MD and HIIT) despite important differences in morphological characteristics and training-induced systemic cardiovascular and thermoregulatory adaptations. [ABSTRACT FROM AUTHOR]

Objectives: There have been increased interests in research on quantifying heat strain of construction workers and formulating corresponding guidelines for working in hot weather. The aim of this study was to validate a subjective measurement tool, the perceptual strain index (PeSI), for measuring heat strain in real-work settings. Methods: A total of sixteen construction workers were invited to participate in the field surveys. Empiric-based human monitoring was carried out with simultaneous micrometeorological (wet-bulb globe temperature, WBGT), physiological (heart rate, HR), and perceptual (perceived exertion, RPE; thermal sensation, TS) measurements throughout the test. The relative heart rate (RHR), the physiological strain index (PSI), and the PeSI were then calculated accordingly. Results: The PeSI exhibited moderate correlations with WBGT and RHR ( r = 0.42 and 0.40, respectively), which indicated the PeSI was sensitive to the variants of WBGT and RHR. The results of regression analysis indicated that the PeSI changed in the same general manner as the PSI, with a relatively large determination coefficient ( R = 0.67). The established perceptual strain zone illustrated that the PeSI ranging from 7 to 8 would be the exposure limit of construction workers in hot weather. Conclusion: The PeSI is a simple, robust, reliable, and user-friendly tool for heat strain assessment in occupational settings. The perceptual strain zone will provide practical guidelines for on-site heat strain monitoring for construction workers. [ABSTRACT FROM AUTHOR]

This study determined the impact of selected chemical protective coveralls (CPC) on physiological responses and comfort sensations. Fifteen males exercised at approximately 6 METS in three CPC (Tyvek®, Gulf and Tychem®) and a control garment. Physiological strain was characterised by core and skin temperatures, heart rate, , perceived exertion, hotness and wetness. Physical burden was characterised by restriction to movement, and RPE. The highest levels of physiological strain and physical burden were found in Tychem®, and the lowest in control. Seven statistical regression models were developed through correlation and multiple regression analyses between the human responses and the results from previously conducted fabric and garment property testing. These models showed that physical burden was increased by adding weight and/or restricting movement. Oxygen consumption was best predicted by clothing weight and fabric bending hysteresis. Fabric evaporative resistance and thickness were the two best predictors of physiological and perceptual responses. Practitioner Summary: Traditional evaluation of chemical protective coveralls (CPC) involves testing at the fabric and garment levels and rarely is based on human trials. This study integrates information from fabric, garment and human trials to better understand physiological strain and physical comfort during prolonged exercise in CPC. [ABSTRACT FROM AUTHOR]

Older experienced firefighters may show signs of heat adaptation, and thus reduced physiological strain, due to repeated occupational heat stress exposure. The aim was to examine physiological and perceptual strain, and hydration, responses to intermittent exercise in the heat in 12 older Non-Firefighter (Non-FF) and experienced Firefighter (FF) males, pair matched for age (Group mean ± SE: Non-FF = 51.7 ± 1.5, FF = 49.8 ± 1.1 years), VO2peak(Non-FF = 39.4 ± 2.2, FF = 40.7 ± 1.8 mL·kg−1·min−1), body surface area (Non-FF = 1.94 ± 0.04, FF = 2.03 ± 0.03 m2), and percent body fat (Non-FF = 24.4 ± 2.3, FF = 19.3 ± 1.8%). Rectal (Tre) and mean skin (MTsk) temperatures, heart rate (HR), local sweat rate (LSR), hydration indices, and ratings of thermal sensation and perceived exertion were measured during 4 ×15-min (rest 15-min) moderate-to-heavy cycling bouts (400 W heat production) in Dry and Humid heat (35°C, ∼20 and ∼60% relative humidity, respectively). No differences were observed between the Non-FF and FF for Tre, Trechange, MTsk, HR,% max HR, LSR, physiological strain index (PhSI), or % plasma volume change. Plasma protein concentration was reduced at baseline for the Non-FF (7.6 ± 0.1 g·100 mL−1) than FF (8.0 ± 0.1 g·100 mL−1). The Perceptual Strain Index overestimated PhSI for Non-FF and FF in both thermal conditions. At the end of exercise, the Non-FF showed a greater Tredifference between thermal conditions (0.27 ± 0.05°C) compared to the FF (0.10 ± 0.09°C). Although the Non-Firefighters and Firefighters demonstrate similar cardiovascular and hydration responses during moderate-to-heavy intensity exercise within each of the thermal conditions, the attenuated thermal effects between the two heat stress conditions in the Firefighters suggests a protective adaptation. [ABSTRACT FROM PUBLISHER]

Anthropometric and physiological factors place the average female soldier at a disadvantage relative to male soldiers in most aspects of physical performance. Aerobic and anaerobic fitness levels are lower in women than in men. Thus, women have a lower overall work capacity and must therefore exert themselves more than men to achieve the same output. The lower weight and fat-free mass and the higher body fat of women are associated with lower muscle strength and endurance, placing them at disadvantage compared with men in carrying out military tasks such as lifting and carrying weights or marching with a load. Working at a higher percentage of their maximal capacity to achieve the same performance levels as men, women tire earlier and are at increased risk of overuse injuries. Their smaller size, different bone geometry and lower bone strength also predispose women to a higher incidence of stress fractures. Although training in gender-integrated groups narrows the gaps in fitness, significant differences between the genders after basic training still remain. Nevertheless, integration of women into military combat professions is feasible in many cases. Some 'close combat roles' will still be an exception, mainly because of the extreme physical demands that are required in those units that are beyond the physiological adaptability capacities of an average female. There is no direct evidence that women have a negative impact on combat effectiveness. Once the gender differences are acknowledged and operational doctrines adjusted accordingly, female soldiers in mixed-gender units can meet the physical standards for the assigned missions. [ABSTRACT FROM AUTHOR]

In COST Action 730, a multi-segmental thermophysiological model was used to describe physiological strain reactions for different climatic conditions in order to develop a 'Universal Thermal Climate Index' (UTCI). UTCI predictions for warm climates were compared with empirical data from the laboratory tests. The comparison was performed by means of equivalence lines within a psychrometric chart so that the combined influence of air temperature and humidity on physiological strain may be assessed. Within a reasonable regime of air temperatures and relative humidities (RH), the differences between simulated and measured values were as follows: for rectal temperatures below 0.3°C, for skin temperatures below 1.5°C, for sweat rates below 200 g/h and for heart rates (estimated from relative cardiac output) below 30 min. This characterises the validity of the model with respect to the description of the influence of heat and humidity on physiological strain. The same comparison to physiological data was also conducted for the equivalent temperature calculated for UTCI. In order to compare UTCI with other thermal indices used in occupational health, the physiological data have also been compared to equivalence lines of WBGT (Wet Bulb Globe Temperature) and PHS (Predicted Heat Strain) indices. [ABSTRACT FROM AUTHOR]

Context: In India, a wide variety of occupations are performed in adverse indoor working environment. Work physiological studies in these jobs are scanty as compared to investigations done on more arduous outdoor occupations. Aims and Objectives: Physiological strain of workers engaged in sweet making activities was assessed in terms of cardiac strain indices in relation to heat stress. Setting and Design: 33 full-time workers from eastern India were compared for cardiac strain profile obtained during summer and winter during their regular work shift. A comparison was also done in between younger (n=12) and older (n=16) subjects. Materials and Methods: Working heart rate (WHR) was recorded continuously during work. The pulse deceleration index (PDI) was obtained from recovery heart rate (RHR). Net cardiac cost (NCC) and relative cardiac cost (RCC) were the main indices used to evaluate physical strain. Thermal stress assessed from wet bulb globe temperature (WBGT). Statistical Analysis: Students' t-test and Wilcoxon signed rank paired tests were used for comparing physiological responses. Values were considered significant when P < 0.05. Results: Work load was significantly higher in summer for all workers. RCC of younger workers in winter and summer ranged between 18% and 26%. This was significantly lower as compared to the RCC of older workers which was 27% in winter and 30% in summer. The physiological workload appeared to be moderate in nature. The WBGT index was above the recommended range in summer for both the groups. Older workers showed a no recovery pattern in terms of recovery pulse that indicated toward a cumulative stress which may be attributed to a combined effect of heat and work in summer and extra amount of work performed in winter season. Conclusion: The physical workload is aggravated with various ergonomic stressors present in the work place. An ergonomic intervention has been indicated as further scope of this study. [ABSTRACT FROM AUTHOR]

People who work in hazardous environments under high physiological stress often have to weigh up the benefits and difficulties of wearing respiratory protection. By developing filter materials that provide comparable smoke particle protection at a significantly lower breathing resistance, exposure to physiological stress may be reduced without jeopardizing protection. In this paper, we investigate to this end the use of stationary electrostatic surface charges, which are known to dramatically improve the efficiency of filter media to fine particles at next to no change in breathing resistance. Filtration test results presented show that some high temperature polymer fiber materials commonly used for personal protective equipment can in fact reach best practice filtration performance if combined with a suitable fiber counterpart. Tribo-electric fiber blends made from combinations of polypropylene with poly-imide-amide, poly(m-phenylene benzimidazole), meta-polyaramid or para-polyaramid have been found to generate significant electrostatic enhancements in nonwoven needle felts that are stable over time. Results suggest that polypropylene is an essential component of fiber blends that reach best practice electrostatic performance with the exception of a meta-aramid fiber blended with wool that appears to work as well. As a result, it is possible to manufacture heat resistant garments for respiratory protection against smoke particles, which could be similar to a bandana and provides protection at a reduced breathing resistance. [ABSTRACT FROM PUBLISHER]

Background: Presumed effects of global warming on occupational heat stress aggravate conditions in many parts of the world, in particular in developing countries. In order to assess and evaluate conditions, heat stress must be described correctly and measured correctly. Objective: Assessment of heat stress using internationally recognized methods. Design: Two such methods are wet bulb globe temperature (WBGT; ISO 7243) and predicted heat strain (PHS; ISO 7933). Both methods measure relevant climatic factors and provide recommendations for limit values in terms of time when heat stress becomes imminent. The WBGTas a heat stress index is empirical and widely recognized. It requires, however, special sensors for the climatic factors that can introduce significant measurement errors if prescriptions in ISO 7243 are not followed. The PHS (ISO 7933) is based on climatic factors that can easily be measured with traditional instruments. It evaluates the conditions for heat balance in a more rational way and it applies equally to all combinations of climates. Results: Analyzing similar climatic conditions with WBGT and PHS indicate that WBGT provides a more conservative assessment philosophy that allows much shorter working time than predicted with PHS. Conclusions: Both methods should be used and validated worldwide in order to give reliable and accurate information about the actual heat stress. [ABSTRACT FROM AUTHOR]

Evidence of the effect of dehydration on physiological responses to hypoxia is limited. The purpose of this study was to determine the effect of hypohydration severity on physiological, renal hormonal and psychological responses to acute hypoxia. Eight males completed intermittent walking tests under normobaric hypoxic conditions (FI O(2) = 0.13) after completing four separate hypohydration protocols, causing change in body mass of approximately 0% (EU), -1% (H1), -2% (H2) and -3% (H3). Physiological and psychological markers were monitored throughout the 125 min test. Fluid controlling hormones were measured pre and post exposure. Heart rate, core temperature, peripheral arterial oxygen saturation (SpO(2)), minute ventilation and urine osmolality were found to be significantly different between hydration conditions and correlated with Lake Louise Questionnaire score (LLQ) (P < 0.05). LLQ score increased with hypohydration severity above H2 (EU 1.3 +/- 1; H1 1.2 +/- 1; H2 2.7 +/- 2; H3 3.9 +/- 2) (P < 0.001). Antidiuretic hormone and aldosterone increased over the test, but were not different between hydration conditions (P < 0.05). Atrial natriuretic peptide showed no change over time, or with conditions. Therefore, renal hormones are not influenced by hypohydration severity during moderate intensity hypoxic exercise. Hypohydration less than -2% induces greater physiological strain during hypoxic exercise and may cause rise in symptoms such as, fatigue, headache, nausea and lightheadedness. [ABSTRACT FROM AUTHOR]