• Korean Journal of Rural Living Science
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• v.8 no.2
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• pp.119-124
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• 1997

In this study we tried to give a decision on propriety of working conditions, to present ideas on reducing work loads, and to grope for efficiency of agricultural works. For this we examined the actual working conditions of cultivating welsh onion in the summer ground. And we improved harmful factors that affect farmer's health by considering results of previous study and farmer's subjective sensation. And we measured. compared, and analyzed the farmer's work loads before and after improvement. The results of this study are as follows ; 1. According to examine the actual working conditions of cultivating welsh onion in the summer ground, farmers have experienced physical and mental chronic fatigue on the basis of farmer's appel to eye - fatigue and sun - burned skin on hot working environment including excessive ultraviolet rays, the rough ground condition, inconsistent arrangement of working stand and sorter, heavy - weared habits, and unsuitable working posture. 2. When we improved harmful factors that affect farmer's health, conformed the effects on important work efficiency index such as heart rate, electromyovolume, body temperature, and microclimate inside clothing and work loads were decreased by eliminating the hillock and obstacles of ground, decreasing the clothing weight, using proper clothing appliances such as hat and sunglasses, controlling height of working stand and sorter suitably, improving the working postures and methods as using assistant appliances, alloting the working time and sequence effectively and presenting the light gymnastic exercises and rest for fatigue restoration.

• Korean Journal of Psychosomatic Medicine
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• v.30 no.1
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• pp.7-15
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• 2022

Objectives : The purpose of this study is to identify the effect of office workers' stress level and stress vulnerability on heart rate variability (HRV), confirm the significance of objective stress indicators obtained through subjective stress and heart rate variability devices, and examine their effectiveness as an integrated stress measurement tool in community mental health projects. Methods : From June to July in 2020, 929 workers participated in the stress management and mental health promotion project carried out by K hospital, and their recorded database was used for study analysis with their agreements. Multiple linear regression analysis was performed to find out the effects of general stress level, and stress vulnerability on heart rate variability. Results : All general characteristics were found to have a significant effect on SDNN (ln), RMSSD (ln), LF (ln), and HF (ln), but work experience did not significantly affect RMSSD (ln). Stress level and stress vulnerability did not significantly affect heart rate variability, but stress perception, a sub-factor of stress level, was found to have a significant effect on RMSSD (ln) (β=0.118, p=0.023). Conclusions : In this study, stress perception, a sub-factor of stress level, was found to be a factor affecting RMSSD (ln). This indicates an association with the activity of parasympathetic nerves in stressful situations, and more follow-up studies are needed to use it as a direct indicator of chronic stress and integrated stress in the community mental health field.

• Journal of the Ergonomics Society of Korea
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• v.29 no.1
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• pp.139-144
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• 2010

Grape weeding work requires Ergonomics improvement, because it performs motion likely to cause Musculoskeletal disorders (MSDs) repeatedly and continuously. The object of this study was to reject workload in Grape weeding works raised MSDs with the Moving Rail-chair and Electromotive Scissors. As objective method of analysis, we used heart rate, EMG, RULA, REBA. As subjective method of analysis, we used questionnaire that indicate lethargy area of body, pain of muscle and bone. As a result, working with Moving Rail-Chair and Electromotive Scissors is lower heart rate and EMG than typical working. Also for the subjective evaluation, reducing of neck and shoulder movement makes improve workload.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.51-53
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• 2006

This paper proposes a portable ECG monitoring system, which integrates uptodate PDA and RF communication technology. The aim of the study is to acquire the subject's biomedical signal without any constraint. It has two types of transmission mode, which are total signal transmission mode and HR(heart rate)/SC(step count) transmission mode. In audition, wireless communication technology uses Zigbee Wireless PAN and can work in low-power mode, which is one of the advantages of ZiBbee communication technology. The developed system is composed of a transmitter and a receiver. The transmitter has three-axial acceleration sensor. ECG amplifier and Zigbee communication controller. In total signal transmission mode, it can send data 50 packets per second whose transmission speed corresponds to 300 ECG samples and 60 acceleration samples. In HR/SG transmission mode, it can calculate heart rate from EEG data with 216 samples per second and step count from acceleration data and send a packet every cardiac cycle. The receiver forwards the received data to PDA, where the data can be stored and displayed. Therefore, the developed device enables to continuous monitoring for Activities of Daily Living(ADL). Also, this method will reduce medical costs in the aged society.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.549-555
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• 2013

Objective: The purpose of this study was to compare the performance of drilling on the ceiling in three different postures (standing, standing on the ladder and supine on the height adjusted board) and the subjective responses of perceived discomfort after the drilling. Background: Overhead work has been identified as a major occupational risk factor and has been a main research subject. Method: Ten young participants drilled 20 holes at the pre-marked places on the ceiling in three different postures. The drilling duration, resting and drilling heart rate were measured. The levels of perceived discomfort at neck, shoulder, elbow, hand and overall body were asked at the end of each task. Results: The working posture affected the heart rate after the drilling. Perceived discomfort in the neck decreased significantly in supine compared to drilling on the ladder. Conclusion: The results of this study suggest that drilling in supine can be an alternative way to reduce the drilling heart rate and the level of perceived discomfort in the neck without sacrificing the productivity. Application: The results of this study would be considered when drilling on the ceiling is required in construction workers.

• Research in Community and Public Health Nursing
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• v.23 no.4
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• pp.395-404
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• 2012

Purpose: This study aimed to identify the health behaviors of working elderly Koreans aged 65 over and examined the socio-demographic and disease-related factors by health behaviors. Methods: This study used data obtained from the 2nd basic survey of the 2008 Korean Longitudinal Study of Ageing. We selected 381 working elderly having one or more of the diseases hypertension, diabetes, heart disease or cerebrovascular disease. Results: 78.9% out of the subjects have hypertension, 31.2% have diabetes, 12.3% have heart disease, and 6.3% have cerebrovascular disease. Compared to the health behaviors of the general elderly, the rate of the practice of regular exercise among the subjects was lower, but the smoking and drinking rate were higher. The significant variables associated with health behavior practice rates were gender, type of work, subjective health status and chronic diseases. Conclusion: The type of work of the elderly with chronic diseases was significantly associated with health behaviors. Consequently, this study found that continuous care programs for the working elderly with chronic diseases should be developed and provided as an occupational health service when the jobs are offered to them.

• The Korean Journal of Physiology
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• v.13 no.1_2
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• pp.1-12
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• 1979

To evaluate the present status of physical fittness of Korean long distance runners, body fat, pulmonary functions, maximal oxygen intake and oxygen debt were measured in 5 elite marathoners (A group), 6 college student runners (B group) and 3 middle school student runners (C group). After laboratory tests, full course marathon running was performed in 2 elite marathoners during which their heart rates were monitored continuously. The results are summerized as follows: 1) Total body fat in all three groups are in the range of 13-15% of their body weight. 2) In all three groups, average values of various pulmonary functions were within the normal limits, but those of tidal volume were higher and respiratory rate were lower in comparison to normal values. These phenomena may represent respiratory adaptations against training. The average resting oxygen consumptions in A,B and C were $322{\pm}23$, $278{\pm}14$ and $287{\pm}16$m1/min, respectively. 3) In all three groups, resting blood pressures were in the normal range, but the resting heart rate was slightly lower in groups A $(56{\pm}3\;beats/min)$ and B $(64{\pm}2\;beats/min)$ and higher in group C $(82{\pm}9\;beats/min)$ in comparison to normal values. These changes in cardiovascular functions in marathoners may also represent adaptive phenomena. 4) During treadmill running the minute ventilation and oxygen consumption of the runners increased lineally with work load in all three groups. When the oxygen consumption was related to heart rate, it appeared to be a exponential function of the heart rate in all three groups. 5) The average maximal heart rates during maximal work were $196{\pm}3$, $191{\pm}3$ and $196{\pm}5\;beats/min$ for groups A,B and C, respectively. Maximal oxygen intakes were $84.2{\pm}3.3\;ml/min/kg$ in group A, $65.2{\pm}1.1\;ml/min/kg$ in group B and $58.7{\pm}0.4\;ml/min/kg$ in group C. 6) In all three groups, oxygen debts and the rates of recovery of heart rate after treadmill running were lower than those of long ditsance runners reported previously. 7) The 40 km running time in 2 elite marathoners was recorded to be $2^{\circ}42'25'$, and their mean speed was 243 m/min (ranged 218 to 274 m/min). The heart rate appeared to increase lineally with running speed, and the total energy expenditure during 40 km running was approximately 1360.2 Calories. From these it can be speculated that if their heart rates were maintained at 166 beats/min during the full course of marathon running, their records would be arround $2^{\circ}15'$. Based on these results, we may suspect that a successful long distance running is, in part, dependent on the economical utilization of one's aerobic capacity.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.182-187
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• 2001

This paper examines the effects on human reaction time and mental fatigue of changes in the intensity of physical activity. A treadmill-equipped instrument and perception tester were used to attain several levels of physical activity. In this paper, in order to determine the individual levels of physical activity of subjects, Borg-RPE scale, Heart Rate(HR) and Respiratory Quotient(RQ) were used. Also, a reaction test in whole-body activity on treadmill-equipped instrument and an addition test as an indicator of mental fatigue were performed. In the above experiments, the scores obtained in addition test administered before and after Physical activity at each intensity level used. Restricted within the limits of this paper, the results of these tests showed that mental fatigue decreased after physical activity.

• Journal of the Ergonomics Society of Korea
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• v.18 no.1
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• pp.1-12
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• 1999

The objective of this study was to investigate the metabolic energy consumption rate of the psychophysical Maximum Acceptable Weight of Loads (MAWLs) for different manual materials handling tasks. Lifting activities with four different lifting frequencies (2, 5, 8, 11 lifts/min) for a lifting range (from floor to 76cm height) were studied. The oxygen consumption rate and heart rate were measured or recorded while subjects were lifting their MAWLs. It was found that the relationship between MAWL and frequency can be described best by the exponential function with the R-sq value 0.9865 for this study. Psychophysical MAWL decreased from 22.38 to 7.48 kg, while the oxygen consumption rate with the MAWL increased from 717.8 to $1114.7m{\ell}-O_2/min$ as the frequency increased from 2 to 11 lifts/min. Heart rate also increased from 104.5 to 120.7 bpm. The ratio of oxygen consumption for the MAWL to the Physical Work Capacity (PWC) ranged from 28 to 43%. The MAWLs were greater than or equal to the Maximum Permissible Limits (MPLs) when the frequencies were higher than 8 lifts/min. It seems that the MAWLs by psychophysical approach when the frequencies were higher than 8 lifts/min tend to be overestimated from the viewpoint of the physiological criterion of the oxygen consumption rates. From these findings it is suggested that the NIOSH Guideline should not be directly applied to Korean without reasonable modifications.

• Safety and Health at Work
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• v.9 no.4
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• pp.468-472
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• 2018

Background: Firefighters are required to use self-contained breathing apparatus (SCBA), which impairs ventilatory mechanics. We hypothesized that firefighters have elevated arterial $CO_2$ when using SCBA. Methods: Firefighters and controls performed a maximal exercise test on a cycle ergometer and two graded exercise tests (GXTs) at 25%, 50%, and 70% of their maximal aerobic power, once with a SCBA facemask and once with protective clothing and full SCBA. Results: Respiratory rate increased more in controls than firefighters. Heart rate increased as a function of oxygen consumption ($V_{O_2}$) more in controls than firefighters. End-tidal $CO_2$ ($ETCO_2$) during the GXTs was not affected by work rate in either group for either condition but was higher in firefighters at all work rates in both GXTs. SCBA increased $ETCO_2$ in controls but not firefighters. Conclusions: The present study showed that when compared to controls, firefighters' hypoventilate during a maximal test and GXT. The hypoventilation resulted in increased $ETCO_2$, and presumably increased arterial $CO_2$, during exertion. It is proposed that firefighters have altered $CO_2$ sensitivity due to voluntary hypoventilation during training and work. Confirmation of low $CO_2$ sensitivity and the consequence of this on performance and long-term health remain to be determined.