Journal of Health and Safety at Work

Introduction: Workers employed in outdoor occupations such as farm working, especially during rice harvest, are exposed to hot and humid environments that put them at risk for different kinds of heat-related disorders or heat stress. The aim of this study was to determine the susceptibility to heat-related disorders and prevention methods among a group of agriculture workers in one of the northern cities in Iran.

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Method and Materials: This study is a descriptive-analytical and cross-sectional study which was done among 340 agricultures workers in a city (Sorkhrood) in Mazandaran province. The samples were collected from 42 villages using two stage cluster-randomized sampling method. The data were collected by means of tailor-made data collection sheet and analyzed using descriptive statistical indexes and Chi- square test, and p<0.05 was considered as significant.

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Results: The findings indicated that the mean values of age and years of experience were 42.8 and 26 years, respectively. Almost half of the agriculture workers were overweight or obese, 34% illiterate, and 15% encountered chronic illnesses. Ninety five percent of the workers were not informed about prehydration in hot environment and none of them know about the consumption of electrolytes. According to Chi-square test result, there were no significant differences between the prevalence of headache as one of the early signs of heat –related disorders and other related factors.

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Conclusion: According to the results, agriculture workers based on their age distribution, education, body mass index, health knowledge, drug use and incidence of chronic diseases, are very vulnerable to heat-related disorders. Therefore, training on recognizing the early signs and doing control measures as essential element in heat stress prevention should be seriously considered.

Introduction: Heat stress is considered as physical hazard, in working environments. The effects of working in hot environment include: muscle cramp, fatigue, loss of consciousness, perception and heat exhaustion.The purpose of this study was to evaluate heat stress and identify hazardous workstations in terms of heat stress in one of the Teheran's forging industries, using WBGT index.

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Methods and Materials: This Cross-Sectional study has been done in one of the forging industries of Tehran on five successive days during the warmest period in Summer 2010. for measurements, a calibrated WBGT meter according to ISO7243 standard was used. All workers who were exposed to radiant heat in this industry, had more than 3 years continuous work history, So they were well accommodated to the environment. For statistical analysis SPSS14 and Exell2007 software were used.

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Results: In this study, the WBGT of all workstations in the exposed to the furnace were estimated. the workstations average WBGTTWA were calculated 27.97°C, Which were higher than the threshold limit value according to ACGIH recommendation. The ANOVA and Post hoc(LSD) tests showed significant difference in the radiant heat (P-value<0.01), and WBGT index (Pvalue<0.05), between three different heights of the body. The observed differences between head and waist were not significant, but the difference between two heights and the ankle were significant.

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Conclusion: Heat stress in workers exposed to the radiant heat sources were higher than the Threshold limit value, which recommended by ACGIH. The results also indicated that the main problem were the radiant heat, especially in the head and waist height. Hence in order to decrease the radiant heat, some control solutions were Suggested.

Introduction: Noise exposure is known as a risk factor for hearing loss and one of its effects is noise-induced stress. Cortisol, as stress hormone- is used in noise-induced stress assessments studies. The aims of this study were:(1) measuring and comparing saliva cortisol concentrations in the morning and evening in normal work day and rest day between two groups, (2) assessing the relationship between industrial noise exposure and salivary cortisol concentrations between two groups.

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Material and Method: Two hundred male workers (100 industrial and 100 office employees) participated in this study. Morning and evening saliva samples were collected at 7 a.m and 4 p.m, respectively. Noise exposure levels were assessed by sound level meter and noise dosimeter. All measurements occurred in two days: one in rest day and other in working day. Descriptive statistics, paired and independent sample t-test and regression analysis were used as statistical tools with α=0.05.

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Result: On the rest day and work day, between morning salivary cortisol was no significant difference in two groups. Comparing evening cortisol concentrations in work day with rest day a significant difference was observed, in worker group, but it was not significant in the other group. The evening cortisol in the working day in was significantly higher among workers than officers.

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Conclusion: This study revealed that industrial noise exposure with levels higher than 80 dBA has a significant effect on salivary cortisol elevation.

Introduction: currently, stress is known as one the most important issue among societies which may have positive or negative results. Stress is caused when there is not a harmony between job demands, capabilities and desires of a person. Most of the behavioral, physical and mental disorders are results of job stress. The objective of this study was Validity and Reliability analysis of NIOSH Generic Job Stress Questionnaire (GJSQ), in order to have an appropriate tool for evaluation and analysis of job stress in Iran.

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Material and Method: In this study, 228 members of Tehran fire-fighting office were chosen according to categorical and clustering sampling, methodology and they completed NIOSH Generic Job Stress Questionnaire (GJSQ). For Validity and Reliability of questionnaire, 20 persons of the group were chosen for content validity analysis of the questionnaire. For Reliability analysis of the result, Cronbach alpha test and in-cluster correlation test were used. SPSS software version 18 was used for analysis of the data.

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Result: The mean age of the participants was 30.8 years (SD=4.9) and the average of job tenure in fire-fighting office was 7.4 years (SD=4.8). In order to reliability analyze the questionnaire, Cronbach alpha coefficient of all influential factors was obtained more than 0.7. In-cluster correlation coefficient of the questionnaire is calculated using retesting on all influential factors. With the exception of Physical Environment and Mental Demands which were about average, all other coefficients were over 0.7, which is a very appropriate result.

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Conclusion: Considering that Validity and Reliability factors of the questionnaire were be appropriate, it can be recommended that NIOSH Generic Job Stress Questionnaire (GJSQ) can be used as a Valid and Reliable questionnaire for job stress evaluation in Iran.

Introduction: Heat stress in workplaces cause multiple problems such as thermal stresses, thermal discomfort and in more severe cases may lead to accidents and diseases related to excessive heat. The aim of this study was to evaluate heat stress adopting WBGT Index in some small enterprise in Qom city and also to examine the relationship between WBGT and physiological indices.

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Material and Method: This Cross-sectional study was conducted in 25 small workshops in Qom city including of 10 indoor and 15 outdoor workshops in August 2012. WBGT were measured according to the ISO7243 standard. The physiological responses including pulse rate, systolic and diastolic blood pressure were measured among 25 workers (one from each workshop).

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Result: The average WBGT index for indoor job were 27.55 Ċ among auto body repair, 27.45 Ċ in mechanics, 24.64 Ċ in painters, 26.73Ċ in welder and 25.89 Ċ in manufacturing doors and windows makers. For outdoor jobs as auto body repair, mechanics and painters it was 30.01 Ċ, and for welders and doors and windows makers 28.52 Ċ. Compared to the standard of ISO7243 WBGT all small workshops were higher than threshold limit. Auto body repair (30.22 Ċ) and painting (30.03 Ċ) workshops had highest WBGT. Average WBGT in auto body repair (as a job with most exposed to the open space and solar radiation) with welder and doors and windows, showed statistically significant differences T-test using WBGT with pulse rate, systolic and diastolic blood pressure did not have statistically significant (P>0.05). The findings indicated that workers are exposing to heat stress and doing more researches and representing preventive counter measures for the workers in this field are essential.

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Conclusion: Heat stress in almost all of the studied workplaces are higher than the recommended limits, and the outdoor workshops had the highest thermal stress, although heat stress did not show a significant correlation with the studied strains.

Introduction: Nowadays, computers are integral component of all workplaces. Moreover, employees healthstatus is directly associated with their occupational stress level. The aim of the present study was to investigative the effect of ergonomic training and intervention on reduction of occupational stress among computer users in welfare organization in Rasht city.

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Material and Method: In this semi experimental study, 283 female computer users, who were 30-40 years old with work experience of 5-15 years, were chosen as sample. The participants had at least one year experience of using computer and they had worked 3-4 hours with computer daily. The Osipow occupational stress questionnaire (1987) with Cronbach alpha 87% was applied for estimation of occupational stress. Then, 46 participants with moderate to high level of stress were selected and randomly divided into case ad control groups. Participants in a case group received practical and theoretical ergonomic training and also interventions (including armrest, foot rest, cushion, posture correction, reduction o work time duration, adjustment of the seat height according to individuals height, adjustment of eye-monitor distance). Finally, the obtained data were compared to those of control group, using covariance.

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Result: According to covariance analysis, ergonomic training and interventions lead to reduction of occupational stress of computer users.

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Conclusion: Training computer users and informing them of the ergonomic principals and also providing interventions such as correction of posture, reducing duration of work time, using armrest and footrest would have significant implication in reducing occupational stress among computer users.

Introduction: Heat stress is considered as one of the hazardous occupational agents in hot environments. Working under heat stress condition may lead to individuals’ health problems. Several studies have been shown that stress in the working environments can elevate stress hormones such as cortisol. Since heat stress is one of the serious stresses in hot industries including melting, this study was done to investigate the effect of heat stress on the cortisol concentration of workers in one of the melting industries.
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Material and Method: In this cross-sectional study, 70 workers in two groups of case and control (35 people in case group from foundry unit and 35 people in control group from casting unit without heat stress) were investigated. First, a demographic questionnaire was complete for each subject. Then in order to evaluate the changes in cortisol level, blood samples were taken from the participants during their working hours (9:30 to 10 AM) and the obtained levels were compared with the normal level of cortisol, provided at 7 to 10 AM. In order to assess environmental condition, WBGT (Wet Bulb Globe Temperature) index was measured at three highest including feet, waist and head. Moreover, noise and lighting were measured at the workers work station. Data were analyzed using SPSS software version 16.
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Result: Regarding WBGT, it was shown that mean WBGT index were 33 C and 16.7 C in case and control groups, respectively. Additionally, cortisol concentration in case group was significantly higher than control group (P<0.001).
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Conclusion: Results of the present study indicate that physical stresses of working environment can lead to changes in physiology of human body. Thus, variations in hormone level in its consequences in hot environment should be considered in occupational hygine.

Introduction: Heat stress is considered as a serious risk factor to the health and safety of workers in most working environments, especially in outdoor works and jobs that workers are exposed to heat due to the working process. This study aimed to evaluate heat stress among workers of brick-manufacturing units in Qom city based on WBGT index as well as the relationship between WBGT and physiological indicators.
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Material and Method: The present study was conducted in 40 brick-manufacturing units in Qom city. WBGT measurements were performed according to ISO7243 standard. Physiological responses of 184 workers (up to 5 people per unit) and also atmospheric parameters were measured. The physiological responses included oral temperature, skin temperature, and temperature for the carotid artery of the ear, heart rate, systolic and diastolic blood pressure. Statistical analysis was done using SPSS software version 16.
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Result: Mean WBGT index for various brick-manufacturing jobs including firing, manual material handling, working with conveyors, molding, and tempering were 30.8 °C, 26.74 °C 26.58 °C and 24.25 °C, respectively and the average WBGT was estimated 27.98 °C. WBGT levels measured in all units exceeded the level provided in ISO7243 standard. The highest mean WBGT was belonged to kiln section (30.8 °C). The mean WBGT at three heights of head, abdomen and legs were not statistically different (using t-test). The correlation coefficients between mean WBGT and mean oral, skin and ears temperatures were 0.203, 0.319, and 0.490, respectively, with the highest correlation belonged to the carotid arteries of ears. Moreover, WBGT showed no significant association with the mean heart rate, systolic, and diastolic blood pressure (P-value>0.05). Indoor and outdoor WBGT index was significantly different (P-value<0.05).

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Conclusion: The level of heat stress in all brick-manufacturing units was higher than the recommended limits, and the workers in kiln unit were more exposed to heat stress, in comparison with other units. Therefore, special countermeasures should be adopted to control heat stress for this occupational group.

Introduction: Working in hot and inappropriate climate condition is one of the most common problems of occupational health which can lead to heat induced diseases and even death. Heat stress may impair the cognitive processes involved in decision-making and converting simple tasks to complex ones. The aim of present study was to assess selective attention and reaction time among workers in a casting unit of a car manufacturing industry and to investigate the effects of heat stress on mentioned variables.

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Material and Method: In this retrospective cohort study 70 workers from a hot industry were selected in two of exposed and control groups. First, demographic questionnaire was completed for each of the participants and noise and light were measured as the likely confounding factors. Stroop test 1, 2, and 3 were done before and during the work in order to determine the effects of heat on selective attention and reaction time. Besides,WBGT were measured at the ankle, waist, and head levels. Data were analyzed using SPSS software, version 18.

Result.: WBGT measurements showed that the mean WBGT were 33 and 16.7 for the exposed and not exposed groups, respectively. Moreover, no significant relationships were observed between test duration, reaction time, and number of errors in Stroop tests 1 and 2 and the level of heat (P-value<0.0001). However, the mentioned variables had a significant positive correlation with Stroop test 3. Additionally, for exposed group variables of test duration, reaction time, and number of errors in Stroop 3 were significantly higher than those of control group.

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Conclusion: According to the findings in present study, heat stress causes an increase in reaction time and a decrease in selective attention. Thus, heat can be assumed as a stressor in hot work environments and the heat should be taken into account while design of job and tasks which needed selective attention or reaction time.

Introduction: Outdoor workers are exposed to heat from solar radiation and the atmospheric conditions, in addition to the heat from the working process, which is worse by global warming. The purpose of this study was to evaluate heat stress based on wet bulb globe temperature index and also to examine the relationship between WBGT and physiological indices among outdoor workers of Shabestar city.

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Material and Methods: This cross-sectional study was conducted in August 2014. WBGT measurements were taken according to ISO7243 standard in different hours. The physiological response of 53outdoor workers (including heart rate, systolic and diastolic blood pressure, oral temperature, and skin temperature) were measured among9occupationalgroups, including municipal workers, concrete makers, porters, construction and road making workers, stonemasons, farmers, traffic officers, and street vendors.

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Result: The mean WBGT index for all outdoor workers, except for municipal workers, street vendors, traffic officers and stonemason, was greater than threshold limit. The highest average WBGT index was for construction workers and the lowest was for municipal workers (respectively 27 and 26 °C). Moreover, a significant direct association was reported between the WBGT index and physiological parameters (P <0.0001), with the highest correlation coefficient belonged to heart rate (r=0.492).

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Conclusion: According to WBGT index, porters, Concrete makers, construction and road makers, and farmers had the highest exposure at all times of the day while the lowest level was related to municipal workers. What is more, heat stress showed a significant correlation with the study strains. Therefore, it is essential to conduct further research and in order to represent preventive countermeasures for the workers in this field.

Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer.

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Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA), and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated.

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Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C) and the lowest value was for plowing (29.98 °C). ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers.

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Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is reduced in different tasks due to heat and this reduction is exacerbated by increase in temperature and might impact the local economy. Thus, further studies are needed to improve the working conditions.

Introduction: Studies have shown that bank clerks experience high levels of stress. Stress is known as the main cause of reduction of job satisfaction and staff commitment and overall organization performance. This study aimed to investigate the association between psychosocial stressors, organizational structure, and job satisfaction.
 

Methods and Materials: This cross-sectional study was performed in 11 branches of a bank in Hamadan. In order to collect data, General Nordic Questionnaire (QPS Nordic 34+), Organizational Structure and Job Satisfaction Questionnaires were used. For determining the relationship between the two variables spearman correlation coefficient was used. Moreover, chi-square test was used to investigate the association between qualitative variables.
 

Results: Job stress (57%) and job satisfaction (39%) of the subjects were in the average level, and structure of the majority of the branches was somewhat inflexible (69%). What is more, there was a significant positive correlation between job stress and dimensions of organizational structure (centralization, formalization). Results manifested a significant correlation between organizational structure and job satisfaction (P-value= 0.05).
 

Conclusion: Considering the effect of organizational structure and work-related psychosocial stressors on job satisfaction, it can be stated that organizational restructuring to achieve organic structures and paying more attention to psychosocial stressors in the workplace, can play an effective role in the efficiency and productivity of the organization.

Introduction: Regarding development of several thermal indices and limitations of each, in this research applicability and validity of temperature- humidity index (Humidex) were examined against the standard heat index, Wet Bulb Globe Temperature -WBGT, as well as tympanic temperature of subjects.

Material and Method:  This cross-sectional study was done on 163 subjects at spring and summer (2013) in outdoor jobs of arid and semi-arid climates of Iran. Environmental parameters as well as tympanic temperature of subjects were measured simultaneously and then heat indices were determined. Data were analyzed using linear correlation charts and Kappa coefficient of agreement by means of SPSS software version 20.

Result: A strong correlation was obtained between WBGT and Humidex in both arid and semi-arid regions (r>0.98), while the correlation between Humidex and tympanic temperature was moderate (r=0.5-0.8). Based on the obtained Kappa value, the agreement coefficient between Humidex and WBGT was 0.878. This value was obtained equal to 0.226 for the Humidex and tympanic temperature.

Conclusion: The results of this study showed that Humidex can be applied as an appropriate substitute for the WBGT index. However, if evaluation of environmental condition with low air temperature or very hot situation is considered, relying only on the Humidex results will not provide a realistic estimation of thermal strain imposed to individuals.

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<0.001). The Pearson’s correlation coefficients were obtained 0.658 and 0.566 respectively, between WBGT index and values of PSI and PSIHR.

Conclusion: WBGT index showed a higher correlation with physiological strain Index; and level of heat stress in all work units of mine was higher than recommended thresholds. Thus, countermeasures should be adopted to control heat stress for the workers in this field.

Introduction: Heat stress is one of the harmful risks in casting and die casting industries, which can not only cause work-related diseases but also can impair the performance and safety of workers. Since the indicators that are used to evaluate heat stress are very different, it is very difficult to choose a suitable index. The aim of this study was to determine the optimum heat stress index in foundry, die-cast, and road construction industries using FAHP and Topsis methods.

Material and Method: In order to determine optimum heat stress index in foundry, die-cast, and road construction industries, first, the prioritization criteria were defined by experts (including ease of measurement, measurement accuracy, comprehensiveness, time, cost, and correlation). Then, considering these criteria, the best heat stress index was determined based on experts’ opinions and using FAHP and Topsis methods.

Result: The results of this study suggest that given the current conditions and criteria, WBGT and P4SR is the best indices for foundry, die casting and construction.

Conclusion: The results showed that according to comprehensiveness, accuracy and correlation criteria, the WBGT index is considered as the best indicator of heat stress assessment in foundry, die-cast and road construction industries. Moreover, the HSI ranked in the last place due to the complexity and cost of its calculation.

Introduction: To evaluate heat stress in the workplace different indices are used. But, none of these measures have been widely accepted. The aim of this study was to determine effective criteria in selecting a heat stress index and weighting of these criteria.

Material and Method:  This study is a qualitative study that was designed and conducted within 10 stages. In the current study, effective criteria for choosing a heat stress index was determined by using Delphi technique and expert’s opinions (30 people), and then the fuzzy analytic hierarchy process was used for weighting and prioritization of these criteria.

Results: Analyzing the completed questionnaires by the experts and according to the percentage of respondents, 11 criteria were finally selected. “Simplicity” criteria by %76.6 had the highest percentage of response. But, the relative weight of this criteria was 0.041, and had the lowest weight after the “low cost” criteria.  The criteria relating to the “Standard” item was 0.141as the highest relative weight.

Conclusion: It can be concluded that the first step to have a reliable and accurate measurement is to choose a proper and correct index. Based on specialists and expert’s opinions, standardization of the index is the most important selection criteria. Other criteria that must be considered were accuracy, reliability and good correlation with the physiological strain indices.

Introduction: Work-Family Conflict can influence the physical and mental health of workers as a social parameter. The aim of this study is supposed to provide theoretical model of relationship between work-family conflict and occupational accidents, taking into account parameters such as job stress and general health of employees in a steel manufacturing industry.

Material and Method: Research population included workers of steel department of a steel manufacturing industry. This research was a cross-sectional study, and 270 individuals were selected in two groups, with an accident experience during lasts 5 years (case) and without (control). They responded to questionnaires including 4 parts, demographic, 18 questions of work-family conflict, 35 questions of job stress and, 28 questions of general health. Data were analyzed and introduced using AMOS software.

Result: Result showed that the model present an excellent goodness of fit and all of factors were significant between parameters (p<0.001). In addition, individual health and job stress with high coefficient could affect work-family conflict and work-family conflict was effective in the event of occupational accidents.

Conclusion: Reducing work-family conflict as a social parameter affecting stress can be effective in the reduction of occupational accidents. The organizational management system with optimization of this important factor can upgrade its level of occupational safety.

Introduction: Nowadays, Snap-fits have many applications in the automotive industry, especially in assembly lines. They are used instead of the mechanical joints such as bolts, the cabling joints, and the car interior lining joints. Due to the special form of these fasteners, they are usually assembled manually. So, the form of clips’ contact area and the sharpness of the Snap-fits may cause the skin pains on the worker’s fingertips. This fact can cause an ergonomic study of these joints for reducing stress on workers and increasing their efficiency and health.

Material and Method: The Finite Element Method (FEM), which is one of the most recognized methods in numeric calculation and computer simulations, is used in order to study the pressures applied to skin due to the pain receptors in the middle layer of skin, and mechanical tensions created in the workers’ thumbs during their work with clips. In order to do this, first a 3D model of a thumb, based on the CT scan data taken from a real thumb sample was created. To identify the different layers of skin, Boolean operations were used. Afterwards, the limit conditions were determined and finally different structures were made to analyze the size, geometric shape and mechanical properties of the clips.

Result: In general, the results show that for those clips that their thumb touching surface is only round in edges, the most pressure on the middle layer of skin decreases as the radius of the round edge increases. Whereas such tensions, lightly increase as the radius increases in those clips that have a hybrid design (the combination of flat and curved surfaces). The result of the material analysis for clips shows that using elastic materials has only a limited effect on reducing tensions (only if rubber like materials are used) and for all tough materials, be it plastic or steel, the intensity of pressure tension would increase in the same manner on all the mentioned items.

Conclusion: The results suggest that during assembly work there are different factors which affect the tension on the fingers, factors like geometric structure, material and mechanical properties. However, the magnitude of those items’ effects are not the same, and that data can be observed while making an ergonomic design for clips.

Introduction: Heat stress is caused by many factors such as individual factors, environmental factors, and management factors. Individual risk factors can decrease the heat tolerance, and play an important role in heat stress disorders incidence. The aim of this study was to review individual parameters influencing the thermal stress and review the preceding studies.

Material and Method: In this review study sites such as Web of Science, Scopus, Pubmed, Iran Medex, Magiran, Google Scholar and SID databases were used for search. The keywords included heat stress, personal factors and heat exposure. The period of 1995 to 2015 was investigated, and finally 75 original articles were identified.

Result: At the individual level, exposure with a single risk factor may reduce the workers’ heat tolerance; while exposure with a combination of several risk factors probably synergistically increases the risk of heat-related disorders. Individual risk factors include age, gender, obesity, fatigue, race, and previous heat disorders and dehydration. In addition, some diseases (such as cardiovascular disease, diabetes and infectious diseases) or use of certain drugs or alcohol can reduce the heat tolerance.

Conclusion: It is necessary to pay attention to the mentioned items when selecting workers in the hot environments. Also, due to the lack of awareness and knowledge of workers, it is necessary to provide appropriate training programs to reduce the effects of heat stress.

Introduction: Job stress is one of the occupational hazards in the modern era. The National Institute for Occupational Safety and Health introduced the nursing job as a top 40 stressful jobs. In this job, multiple training techniques are considered to reduce stress and stress factors. This study was conducted to response the question “Is the use of health education programs can be effective in reducing job stress?”

Material and Method: Electronic search was done using key words in Persian and English database (Medical Sciences, Iran Medex), Scientific Information Database (SID), Bio Med Central, Pub Med, Science Direct) and were found 3,412 paper totally. Articles examined based on defined criteria and 9 qualified articles were discussed systematically.

Result: Among the reviewed studies, educational interventions in 7 studies were without, and 2 studies were with the use of health education models. The results of studies indicated significant effect of educational interventions on reducing job stress and using health education models in interventions had a greater effect on reducing job stress.

Conclusion: The results highlights the importance of educational interventions based on health education models to reduce occupational stress among nurses.