高温环境下不同体力劳动强度对心血管负荷指数影响研究

基于心率变化的心血管负荷指数作为评估人体疲劳程度的指标之一,得到国内外专家学者的广泛研究。为进一步研究高温环境下不同体力劳动强度对心血管负荷指数的影响,探讨高温作业下不同劳动强度人体疲劳程度的变化,分析出不同温度下人体可接受的体力劳动强度。通过采用实验仓模拟不同的高温环境,以心血管负荷指数(%CVL)作为人体疲劳程度的分级指标,最终得到了高温环境下从事不同体力劳动强度的心血管负荷指数回归方程,以及不同高温环境下人体可承受能力下可进行的体力劳动强度,为高温环境劳动者制定合理和健康的作业安排提供科学依据。     

Ergonomics in Practice: Physical Workload and Heat Stress in Thailand

This study consists of assessments of the thermal environment and physio-logical strain in tasks associated with airport, construction, and metal jobs. The number of male and female participants was 108. Environmental heat stress was evaluated with the WBGT index. Physiological strain was evaluated by the relative cardiovascular load (%CVL) based on the measurements of heart rate. Also the increase of body temperature, weight loss, and perceived discomfort were determinated. At work sites the assessments lasted for 2 to 4 hrs for each participant. The mean physiological strain exceeded the level of 30%CVL. Severe peaks (over 60%CVL) were observed in specific tasks being in agreement with perceived discomfort ratings. The increase of body temperature and weight loss in most cases remained within acceptable limits. For the most strenuous tasks, various ergonomic improvements were developed in consultation with workers and managers.     

Cardiovascular Load During Summer Work of Two Age Groups of Van-Rickshaw Pullers in West Bengal,India

Van-rickshaw is a popular mode of transport of people and merchandise in developing countries. The purpose of this study was to assess the effect of age on cardiovascular load of van-rickshaw pullers in the summer season (March-June) in real situations. In 142 participants, divided into 2 age groups (25-40 and 41-55 years), cardiovascular load was assessed on the basis of working and partial recovery heart rate (HR), predicted maximal HR, working maximal HR, average working HR, percentage of reserved HR, sum of recovery heart beats, percentage of recovery, relative and net cardiac cost, etc. Except for percentage of recovery, all parameters differed significantly between the groups and were significantly correlated with age. As this activity is very stressful, it places a heavy demand on the cardiovascular system. Therefore, age is an important factor for sustainability of the work, especially in a hot environment. Some ergonomic interventions are necessary to reduce cardiovascular load.     

Traumatic work-related fatalities in forestry and sawmill workers in Australia

Work-related traumatic forestry and sawmill fatalities were studied as part of a larger study of all work-related traumatic fatalities in Australia from 1982 to 1984. Data on 79 cases were obtained from inspection of coroners' files. The fatality incidence per 100,000 person-years was extremely high for loggers (396), and high for forest service workers (52) and workers employed in sawmills (30), compared to the entire Australian workforce (8.1). Felling/trimming trees, traffic-related activities and operating heavy machinery (forestry workers) and loading/unloading logs and operating bench saws (sawmill workers) were the most common tasks being performed at the time of the fatal injury. Being struck by a falling tree, often one that had been disturbed by the tree being felled, was the most common mechanism of fatal injury. Isolation, poor work practice, errors of judgement, and equipment problems were the most common contributing factors to the fatal incidents. Emphasis on correct work practice and training (especially in felling), equipment maintenance, and availability of communication and medical retrieval in isolated areas are recommended.     

Occupational noise exposure and hearing defects among sawmill workers in the south of Thailand

The aim of this study was to investigate occupational noise exposure and hearing defects among sawmill workers in the south of Thailand. Seven hundred sawmill workers participated, of which 335 (47.9%) were male. The mean age of the sawmill workers was 33.5 years (SD 10.2), and more than 60% were <35 years old; 75.1% of the workers had less than 5 years of work experience. Only about one in four workers (25%) had been trained in use of personal protective equipment (PPE), and half of the participants never or rarely wore PPE while working. The prevalence rate of noise-induced hearing loss (NIHL) was 22.8% (N?=?42). Male workers had significantly higher risk than female workers (odds ratio [OR]?=?2.21). Workers aged older than 25 years had significantly higher risks for NIHL (OR?=?3.51–12.42) than workers younger than 25 years. Sawing workers had higher risk for NIHL than office workers (OR?=?3.07).     

Mental Workload and Health: A Latent Threat

The aim of this study is to investigate changes in cardiovascular activity associated with a high mental workload. The reported experiments, carried out in naturalistic settings, point to information load and information processing under time pressure as main risk factors. This kind of occupational stress had to be dealt with by two of the three groups under investigation: brokers and simultaneous interpreters; it was not experienced by lecturing university professors. The pattern of cardiovascular activity of the two former groups consisted of overmobilization of cardiovascular activity at the beginning of work, and only partial normalization of task-evoked changes in cardiovascular activity at the end of work. Substantial elevations of diastolic blood pressure and tachycardia, which followed earlier overmobilization, resemble a miniature copy of changes seen in the development of cardiovascular diseases.     

Physiological evaluation of chemical protective suit systems (CPSS) in hot conditions.

This job-related experiment investigated physiological strain in subjects wearing impermeable chemical protective suit systems (CPSSs) weighing about 28 kg. Two types of CPSSs were studied: the self-contained breathing apparatus was carried either inside or outside the suit. Eight healthy and physically fit male firefighter instructors aged 32 to 45 years volunteered for the study. The test drill, performed at a dry, windless ta of 40 degrees C, was divided into 2 consecutive work sessions of 14.5 min (a 20-min rest between) including typical operational work tasks. Considerable thermal and maximal cardiovascular strain and intense subjective discomfort measured in the firefighters emphasize the need to limit working time in hot conditions to only 10-12 min while wearing CPSSs. The present results indicate that the exceptionally heavy physical load and psychological stress during operations in chemical emergencies must be considered in the assessment of the cardiovascular capacity of ageing firefighters using CPSSs.     

Predicting work performance in nuclear power plants

Diagnosis and monitoring are the major tasks of an operator in main control room of nuclear power plants (NPPs). The operator’s mental workload influences his/her performance, and furthermore, affects the system safety and operations. This study investigated the operator’s mental workload and work performance of the NPP in Taiwan. An experiment including primary and secondary tasks was designed to simulate the reactor shutdown procedure of the fourth nuclear power plant (FNPP). The performance of the secondary tasks (error rate), subjective mental workload (NASA Task Load Index, NASA-TLX) as well as seven physiological indices were assessed and measured. The group method of data handling (GMDH) was applied to integrate these physiological indices to develop a work performance predictive model. The validity of the proposed model is very well with R² = 0.84 and its prediction capability is high (95% confidence interval). The proposed model is expected to provide control room operators a reference value of their work performance by giving physiological indices. Besides NPPs, the proposed model can be applied to many other fields, e.g. aviation, air transportation control, driving and radar vigilance, etc.     

A survey of forest workers in New Zealand. Do hours of work, rest, and recovery play a role in accidents and injury?

PROBLEM: A number of structural and organizational changes have occurred recently within the New Zealand Forestry Industry, with concerns being raised about the impact of these changes on the forestry worker in terms of fatigue, sleepiness, and compromised safety. This study explored the relationship of fatigue, and some of its key determinants, with accidents and injuries in a group of forestry industry workers in New Zealand. METHOD: A total of 367 forestry workers responded to a self-administered questionnaire. RESULTS: Fatigue was found to be commonly experienced at work in the forest, with 78% of workers reporting that they experienced fatigue at least "sometimes." This study found that certain groups of workers reported long working hours, reduced sleep, compromised recovery time, and intensely paced work. The results of logistic regression analysis showed that recent sleep, number of breaks taken during the workday, and specific job/tasks were independently associated with reporting of high fatigue levels at work. Near-miss injury events were significantly more common among those reporting a high level of fatigue at work. Accidents and lost-time injury were associated with length of time at work, ethnicity, and having had near-miss injury events. DISCUSSION: Together, these results suggest that fatigue and aspects of work organization, which are likely to be fatiguing, may be associated with compromised safety for forest workers. IMPACT ON INDUSTRY: With an already slim margin of error present in forest operations, an impairment due to increased fatigue may constitute a significant risk factor for accidents and injuries in this workforce. The results indicate the need for further examination of shift and workload management among forestry workers, as well as a role for improving industry awareness about the causes and consequences of fatigue.     

A study of the workload of underground trammers in the Ranigang coal field area of West Bengal, India.

Thirty healthy trammers were examined in underground haulage mines during their normal activity. Physiological strain in terms of heart rate (HR) varied between 101.6 and 104.7 beats/min with mean net cardiac cost of 33.06 and 34.06 beats/min for younger and older groups respectively. The average relative cardiac cost was lower for younger subjects than for older ones. Oxygen consumption (VO2) was measured with an Oxylog-II machine (UK); subsequently values were estimated. Maximum aerobic capacity was estimated with an indirect method following a standard step test protocol. The responses revealed that the average VO2 during the activity was 0.75 and 0.8 L/min, which corresponded to energy expenditure (EE) of 3.8 and 3.97 Kcal/min for younger and older subjects respectively. The workload in terms of HR and EE was moderate, whereas the aerobic strain experienced by aged workers was above the acceptable level.     

Thermal Strain in Fire Fighters While Wearing Task-Fitted Versus EN 469:2005 Protective Clothing During a Prolonged Rescue Drill

Fire fighters are normally overprotected during their working hours because of the tendency to keep the personal protection level sufficiently high in case of the worst possible scenarios. This study investigated the effects of task-fitted protective clothing on thermal strain in fire fighters as compared to EN 469:2005 protective clothing during a prolonged (2 1/2 hrs) job-related rescue drill under neutral and hot climates. The subjects were 23 healthy, physically fit professional male fire fighters aged 26–44 years. Measurements included cardiovascular and thermal responses and subjective assessments. Wearing task-fitted clothing during rescue tasks in a neutral climate considerably reduced total thermal and cardiovascular strain in prolonged rescue work. The fire fighters also perceived physical work as significantly harder on average, and reported more intense subjective discomfort while wearing EN 469:2005 as compared to task-fitted clothing.     

Assessment of Physical Load at Work Sites: A Finnish–German Concept

The aim of this article is to introduce a set of work physiology methods for the assessment of physical load at the work site and to consider (a) their relevance for different types of muscular work, and (b) their feasibility for occupational health and safety practitioners. The results of an ergonomic intervention study for the reduction of workload associated with various manual materials handling tasks were used for the evaluation of the feasibility and sensitivity of the measurements of heart rate, the Edholm and OWAS methods, and the ratings of overall and local perceived exertion. The methods proved feasible, although time consuming, and their sensitivity for the quantification of small changes in physical workload was limited. Despite these shortcomings, these methods can be used by occupational health and safety practitioners when their strategy and data collection techniques are developed further. In conclusion, there are relevant and feasible methods fora reliable work-site assessment of cardiorespiratory and postural load related to the activation of large muscle masses. On the other hand, field methods for the quantification of local static workload and repetitive type of workload with small muscle masses are scarce.     

Effectiveness of a Light-Weight Ice-Vest for Body Cooling While Wearing Fire Fighter’s Protective Clothing in the Heat

The aim of the study was to examine the effects of wearing an ice-vest (ca 1 kg) on physiological and subjective responses in fire fighters. The experiments were carried out on a treadmill in a hot-dry environment. The physical cooling effect of the ice-vest was measured with a thermal manikin. The ice-vest effectively reduced skin temperatures under the vest. On average, heart rate was 10 beats/min lower, the amount of sweating was reduced by 13%, and subjective sensations of effort and warmth were lower during work with the ice-vest compared to work without it. Thermal manikin tests indicated that the useful energy available from the vest for body cooling was rather high (58%). In conclusion, the ice-vest reduces physiological and subjective strain responses during heavy work in the heat, and may promote efficient work time by 10%.     

Changes in logging injury rates associated with use of feller-bunchers in West Virginia

Problem: It is well documented that logging is one of the most dangerous occupations and industries in which to work, and trees fellers are at greatest risk of injury. The objective of this study was to determine whether West Virginia (WV) logging companies experienced a reduction in injuries after beginning to use feller-bunchers (tree cutting machines, which replace some of the work done with a chainsaw) during harvesting operations. Methods: WV workers compensation claims and employment data from 1995 to 2000 were used to calculate injury rates. Injury trends in the rest of the WV logging industry, not using feller-bunchers, were also assessed. Results: For 11 companies, the pre-feller-buncher injury claims rate was 19.4 per 100 workers and the post-feller-buncher rate was 5.2 per 100 workers. This was a significant difference, with an adjusted rate ratio of 2.8 (95% CI: 1.8–4.5) of pre to post claims. Struck by injuries also showed significant decline, with the pre-feller-buncher injury rate being 3.8 (95% CI: 1.8–8.2) times as great as post-feller-buncher rate. During the time of the study, the injury rate rose in the rest of the WV logging industry. The average cost of a workers compensation claim in the WV logging industry during the time of the study was approximately $10,400. Impact on industry: As mechanization of logging tasks becomes more widespread, the WV logging industry as a whole may see substantial injury declines and a reduction in the total cost of injury claims. Struck by injuries, the most common and potentially fatal of logging injury types, appear to be particularly affected. However, logging operations in areas of very steep terrain where it is not possible to use these machines may need to rely on strategies other than feller-bunchers to reduce injuries.     

Ergonomics and Work Organization: The Relationship Between Tayloristic Design and Workers’ Health in Banks and Credit Cards Companies

Abstract

The discussion developed in this paper is based on the results of an ergonomic work analysis carried out with attendants at call centers. Some critical issues and difficulties, like working pace, inadequate tools and workstations, and software inadequacies were detected in working situations. Operator-customer interactions are presented, attempting to put in evidence working constraints, working conditions, and their connection with health problems.

The main conclusion is that serving clients, especially when the job is to provide information, is not a simple task, as information is not always available in the computerized system and is completely fragmented. The scope of workers’ actions is very restricted and complicated and recurrent requests are redirected to others. Workers (individually or as groups) have limited possibilities to make adjustments to be able to give more adequate and personalized treatment to clients and, at the same time, to work in a less stressful environment. In periods of increased workload and work intensification, the situation is very much favorable to the incidence of health disorders, such as work related musculoskeletal disorders (WMSD) and others. Some suggestions to improve the work situation are discussed.     

The impact of job demands and behavioral control on experienced job stress

The present study examines the impact of behavioral control on the experience of work strain under conditions of work overload. Extending experimental laboratory findings that suggest that control can lessen the impact of aversive stimuli on psychological and physiological strain responses, we hypothesized an interaction between control and workload such that the effects of high demands on strain would be less if the worker had behavioral control over the task. This hypothesis is also consistent with Karasek's job demands-job decision latitude model of work strain and health. The hypothesis was tested in a laboratory experiment in which 125 subjects worked on a mail sorting task with either a high or moderate level of workload and either a high or low level of behavioral control. Strain responses were assessed with measures of job satisfaction, anxiety, and physiological arousal. The hypothesis was only partially supported in that high control lessened the impact that work overload had on anxiety. While not fully supportive of the model, the results are seen as conservative given the constraints on the manipulation of work overload inherent in the laboratory environment.     

有限空间作业人员生理状态监测设备研制

为监测有限空间作业人员异常生理状况,进而保障有限空间作业安全与作业人员生命健康,在分析手腕处6个测量位置信号质量的基础上,获得最佳信号采集位置,并结合事故成因,从光电容积脉搏波(PPG)信号中提取心率、脉搏周期、振幅等生理参数作为评价指标,研制一款针对有限空间特殊作业人群的手腕处脉动生理信息监测设备;并进行系统稳定性测...     

Noise exposure as related to productivity, disciplinary actions, absenteeism, and accidents among textile workers

A sample of 2458 workers exposed to average noise levels ranging from 80 to 99 dBA in different operations of three textile mills was studied with respect to their productivity, work rule violations, absenteeism, and accidents. The three mills were in rural, suburban, and urban locations. Noise exposure levels were measured in individual departments of the mills, and workers were interviewed to ascertain socioeconomic background, work history data, and health status. Workers' job attitude was rated by their supervisors, and data about their productivity, disciplinary reports, absenteeism, and accidents were collected from plant records. Results of the study suggested that workers in departments with high noise levels (above 90 dBA) had more disciplinary actions and absenteeism and lesser productivity than those in departments with low noise exposure (below 90 dBA). Disciplinary actions showed the greatest difference between the high-noise and low-noise departments followed by production incentives, production efficiency, and absenteeism. Noise appeared to affect the quality of work as reflected by disciplinary actions for material damage, and this effect was higher in weaving and spinning operations which involved vigilance tasks. The frequency and severity rates of accidents in highnoise departments were greater than in low-noise departments. Certain personal and socioeconomic factors affected high vs. low noise exposure differences found among workers for the investigated variables. These effects were most apparent for absenteeism and, to a lesser extent, productivity. Disciplinary actions did not appear to be influenced by any such individual factors. It was concluded that noise abatement in the textile industry could be beneficial to worker productivity and well being and contribute to more economically effective operation.     

煤矿工人体能负荷与工伤事故关系研究

体力负荷过重而导致疲劳是引起事故不可忽视的重要原因之一.为研究煤矿井下工人体能负荷对工伤事故发生风险的影响,选择北京XX煤矿作为调查对象,测定井下不同岗位矿工的劳动负荷和疲劳指数,回顾性调查近5年内各类工伤事故发生情况,进而分析与工伤事故发生的关系.统计分析结果表明,在疲劳状态下事故发生的危险性明显增加;劳动负荷越重,疲劳越重,事故发生率也相对较高.减轻疲劳对预防事故与保证工作安全具有很重要的意义.     

Stress and mental strain in hospital work: Exploring the relationship beyond personality

This study focuses on the relationship between job stressors and mental strain in hospital work, adjusting for differences in personality traits. Questionnaires were obtained from 760 full-time employees. Fourteen scales of job stressors were clustered into four factors: professional latitude, clinical demands, workload problems and role difficulties. A mental strain index was derived from the addition of three sub-scales: depression, anxiety and irritation. Two personality traits were measured: Locus of Control (Rotter) and Striver-Achiever (Sales). The four job demand factors were dichotomized into high-low grouping variables. A 2⁴ factorial analysis of covariance was conducted, using the two personality traits as covariates, in order to test and adjust for trait-related strain. Results show that Locus of Control adjusted differences in mental strain appear significantly related to work stressors. A direct relationship was found with role difficulties, professional latitude and workload problems. Moreover, high levels of role difficulties and low levels of professional latitude interact significantly with adjusted levels of mental strain. The Striver-Achiever trait, however, appears most strongly correlated with workload problems but not with mental strain. We believe that this exploratory analysis suggests that the stressor-strain relationship might be best conceived as a combination of direct and complex pathways, relating facets of both job demands and of personality with outcomes, under a cognitive and conditional paradigm.