• Safety and Health at Work
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• 제9권4호
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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.

• 한국농촌생활과학회지
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• 제8권1호
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• pp.7-13
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• 1997

In this study we examined the greenhouse worker's work load to test the efficiency of the developed vehicles (hand operated vehicle (HV), simple battery-powered autonomous vehicle (AV)). The subject of this study were healthy adult females who had experience in growing crops. We measured workers' heart rate, blood Pressure. rectal temperature, mean skin temperature, oxygen consumption and blood lactate level as a physiological index of work load. The results of this study are as follows : The test group using experimental vehicle showed the lower heart rate (mean$\pm$S.D. for HV, AV respectively 74$\pm$5, 75$\pm$3 beats/min, p＜0.01) than the control group (84$\pm$8beat/min) not using experimental vehicle and the lower systolic blood Pressure (HV, AV respectively 109$\pm$8, 109$\pm$9 mmHg, p＜0.01) than the control group (121$\pm$11 mmHg), and lower rectal temperature(HV, AV respectively 37.0$\pm$0.1, 36.8$\pm$0.2$^{\circ}C$, p＜0.01) than the control group (37.0$\pm$0.2$^{\circ}C$), and the less oxygen consumption (HV, AV respectively 2.13$\pm$0.09, 1.66$\pm$0.52$m\ell$/kg/min, p＜0.01) than the control group(2.43$\pm$0.12$m\ell$/kg/min), and the lower blood lactate level (HV, AV respectively 2.03$\pm$1.00, 1.66$\pm$0.52mmol, p＜0.01) than the control group (2.43$\pm$0.12mmol). Judging from these results, these experimental vehicles for greenhouse workers can be confirmed as a useful tool. It is suggested that these vehicles would alleviate the peasant's syndrome including muscle fatigue and musculoskeletal disease usually caused by working in an uncomfortable posture.

• 대한족부족관절학회지
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• 제17권4호
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• pp.288-293
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• 2013

Purpose: Number of arthroscopic surgery is gradually increasing with development of its equipment and technique. Arthroscopic ankle surgery performed with the traction device has various complications and need more time for preparation. We investigated whether the complication rate increased when surgery was performed without the traction device, and compared the complication rate of arthroscopic surgery with the traction device. Materials and Methods: From January 2009 to June 2012, arthroscopic ankle surgery was performed without the traction device in four hundred eleven cases. There were two hundred sixty-one males and one hundred fifty females. The average age at operation was 35 years (range, 17-56), and the average follow up period was 28 months (range, 12-41). Postoperative symptoms and complications were checked. Results: There were difficulties performing arthroscopic surgery without the traction device in five cases with severe traumatic osteoarthritis. However, after burring and shaving, we had enough space to work on. Superficial peroneal nerve symptom was found in two cases, grooving of talus was found in 11, and saphenous vein injury was found in five. Since preparing for the traction device was unnecessary, we were able to save time with the mean duration of surgery of 50 minutes (range, 30-120). Conclusion: With only manual traction, we could explore the entire ankle joint without damage on cartilage. Yet, skilled arthroscopic technique will be necessary for arthroscopic surgery without the traction device.

• International Journal of Internet, Broadcasting and Communication
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• 제13권3호
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• pp.130-136
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• 2021

The purpose of this study was to investigate the effect of the intensity of warm-up exercise on the physiological response and exercise performance during resistance exercise. For this purpose, 8 male college students with at least 1 year of experience in resistance movement were selected. The warm-up condition was set to NON condition (preparatory exercise not performed), 3 set condition, 6 set condition, and 9 set condition, and the intensity was different for each set. After warm-up, 75% 1RM of main exercise was performed, and blood pressure and heart rate were measured immediately after exercise to measure RPP. The number of repetitions and total work for each condition were measured as the number of repetitions and momentum during the main exercise. The measured data were analyzed by repeated measures two-way ANOVA. As a result, although there was no difference in Rate Pressure Product according to the warm-up conditions, the number of repetitions and total amount of exercise showed the highest in the 3-set condition. Therefore, it is thought that the number and intensity of warm-up exercises should be set appropriately during resistance exercise, and warm-up of 3 sets or more during resistance exercise is thought to decrease exercise performance.

• 산업경영시스템학회지
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• 제24권69호
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• pp.51-64
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• 2001

A laboratory experiment was conducted to investigate the effects of working posture. work/rest ration, and task type on the physical workload in automobile assembly jobs. Ten healthy male university students participated as subjects in the experiment. East subject performed 18 experimental session with combination of 3 working posture 3 work/rest ratio and 2 task types. To examine the effect of various working conditions on workload, DMG analysis was performed on 4 different muscles in the neck an arm area, Also RPE scale and heart rate were taken as response variables. The result showed that all working conditions considered in the experiment had significant effects on the workload concluding that labor intensity in auto assembly jobs should be adjusted with respect to different levels of working posture, work/rest ratio, and task type. Detailed analysis are presented in the paper.

• 한국전문물리치료학회지
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• 제8권3호
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• pp.77-95
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• 2001

The purpose of this study was to investigate the effects of resting periods between exercise sets during isokinetic contraction on recovery from muscle fatigue, strength, heart rate, blood pressure, and lactate level. Sixteen women performed 10 repetitions of isokinetic exercise for three sets in three different conditions. During the sets, they rested 50, 100, and 150 seconds in each condition. And the results were: 1) In this population, the peak torque of extensor during the isokinetic exercise in 100 second resting condition was significantly higher than that in 50 and 150 second resting conditions (p<.01). The total work of extensor was significant in the second and third sets in 50 and 100 second resting conditions (p<.01). 2) During the isokinetic exercise, the heart rate was progressively increased as the sets were advanced in all resting conditions (p<.01). And the increase was significant during the second and third sets than the first in 50 second resting condition (p<.01), while it was significantly greater after the third set than the first in 100 and 150 second resting conditions (p<.01). 4) No difference was found between the resting periods in blood lactate level and blood pressure during the isokinetic exercise. However, differences were found between the sets in these variables (p<.01).

• 대한간호학회지
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• 제25권3호
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• pp.538-548
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• 1995

Exercises are achievement oriented, the process is frequently perceived as hard and difficult Participants drop out from exercise programs in the middle of the training period. Dance movement, which is the deliberate and systematic use of movement, is enjoyable during the movement and provides opportunities for persons to express them-selves. Regular long term dance movement may in-duce a training effect with a decreased drop out rate. Dance movement could be one way to attain wellness, however, there have been few studies to evaluate both physiological and psychological aspects of dance movement. This study focused on evaluating the effects of dance movement training on body weight, resting blood pressure and heart rate, limb circumference and strength, stress response and subjective feelings. This quasi-experimental study was designed as a nonequivalent control group pre test -post test study. Ten healthy fe-male subjects, aged between 19 and 31 years volunteered for an eight week dance movement program. Ten healthy female subjects, between 19 and 21 years of age paticipated as controls. None of the subjects had performed regular physical activity for six months prior to the study. Dance movement was created with reference to Heber's movement guide. The Dance movement program consisted of approximately 30 minutes of dance, three days per week, for eight weeks. During each 30 minute work out, there were approximately 5 minutes of warm-up dancing, 20 minutes of conditioning dance and 5 minutes of cool-down dancing. The intensity for the conditioning phase was at between 60% and 65% of age-adjusted maximum heart rates. Body weight, resting blood pressure and heart rate, circumference of mid upper arm, mid thigh and mid calf, muscle strength of upper and lower limb, physical and psychological response to stress were measured prior to, and following the experimental treatment. Body weight was measured by digital weight scale(Kyung In Corp., Korea). Resting systolic and diastolic blood pressure were measured by sphygmomanometer, Resting heart rate was measured for one minute in a relaxed sitting position using the radial artery. Circumference of mid upper arm, mid thigh and mid calf was determined by tape measure. Muscle strength of the upper extremities was measured by a grip dynamometer (Takei Corp. No.1857, Japan) and that of the extremities was measured by the length of time the leg could be held at 45° Physical and psychological responses to stress were measured using the Symptoms of Stress (SOS)Scale. Paticipants in the dance movement were interviewed by the facilitator following the eight weeks, and their thematic responses about the dance movement were recorded. Following the eight week dance movement train-ing, body weight decreased significantly, circumference of mid thigh and mid calf increased. The length of time leg - raising could be held tended to increase following the dance movement training. Resting systolic and resting heart rate showed a tendency to decrease. Total mean score of stress response tended to de-crease, and mean score of habitual patterns, do-pression, anxiety / fear, anger and cognitive disorganization decreased remarkably following the eight week dance movement. Thematic responses about the dance movement were positive following the training.

• The Korean Journal of Physiology
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• 제1권1호
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• pp.83-90
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• 1967

In order to evaluate the accuracy of the measurement of maximal oxygen intake (MOI), the MOI in seven subjects was determined 3 to 4 times in each individual. Following a 10 minute warm-up on treadmill (4.3 km/hr with 9 degree grade), the subject was asked to run at a speed of 8.73 km/hr on treadmill for a period of 3 minutes at a given grade which was elevated in a step-wise manner from zero to the level of exhaustion. Following a 3 minute run, the subject was allowed to rest for a period of 3 to 5 minutes. During each period of running, several cardio-pulmonary functions were determined and the range of variability for each measurement was computed. The oxygen consumption during the maximal work load was taken as the MOI. The results may be summarized as follows: (1) The minute volume, the oxygen consumption and the heart rate increased linearly until the grade was elevated to 9 degree above which these values were leveled off. (2) The minute volume and the heart rate during maximal exorcise were $87.4{\pm}8.10\;1/min\;and\;187{\pm}3.7$ per minute, respectively. (3) The maximal oxygen intake which corresponds to the oxygen consumption during maximal exercise was averaged to 3.04 1/min. (4) The coefficient of variance for the maximal oxygen intake was 6.32% while the corresponding values for the minute volume and the heart rate during maximal exercise were 5.22 and 2. 14%, respectively.

• Safety and Health at Work
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• 제13권2호
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• pp.148-154
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• 2022

Background: Bus driving is a mentally demanding activity that requires prolonged attention to ensure safety. The aim of the study was to assess mental fatigue caused by driving a public bus and to find a profile of workers at higher risk. Methods: We evaluated changes of critical flicker fusion (CFF) (index of central arousal) and heart rate variability (HRV) (index of autonomic balance) in a 6-hour driving shift on a real route, in 31 professional bus drivers, and we tested the influence of personal factors such as sleep quality, BMI, and age. Paired t-test was used to test differences of CFF and HRV between both initial and final phase of driving, while multiple linear regression tested the influence of personal variables on the indexes of mental fatigue. Results: Results showed that CFF significantly decreased after 6 hours of bus driving (41.91 Hz, sd 3.31 vs. 41.15 Hz, sd 3.15; p = 0.041), and heart rate significantly decreased in the final phase of driving, with respect to the initial phase (85 vs. 78 bpm, p = 0.027). Increasing age (beta = -0.729, p = 0.022), risk of obstructive sleep apnea syndrome (beta = -0.530, p = 0.04), and diurnal sleepiness (beta = -0.406, p = 0.017) showed a significant effect on influencing mental fatigue. Conclusion: Elderly drivers at higher risk of sleep disorders are more prone to mental fatigue, when exposed to driving activity. Monitoring indexes of central arousal and autonomic balance, coupled with the use of structured questionnaires can represent a useful strategy to detect profile of workers at higher risk of mental fatigue in such duty.

• 인간식물환경학회지
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• 제24권6호
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• pp.639-649
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• 2021

Background and objective: Various images from visual display terminals (VDTs) as well as living lighting are important parts of our daily life; thus, properly controlling the lighting environment - that is, illuminance, color temperature and good images from VDTs - can have a substantial effect on improving the mental health and work efficiency in everyday life. We examined electroencephalography (EEG) and heart rate variability (HRV) responses to various lighting conditions in 25 university students as they viewed images of a green landscape or traffic congestion. Methods: EEG was performed in darkness and when the room was illuminated with 10 different light-emitting diode (LED) color temperatures, while the EEG and HRV responses to green landscape or traffic congestion image stimuli were measured in darkness and during room illumination with three different LED color temperatures. Results: We found a significant difference between darkness and high LED illumination (400 lx) at 7 (CZ, F4, FZ, O1, O2, OZ, and T6) of 30 channels, while the alpha wave activity increased during darkness. In the second experiment, the green landscape image stimuli in the 30 lx-2600 K lighting condition elicited theta wave activity on the EEG, whereas the traffic congestion image stimuli under high LED illumination elicited high beta and gamma wave activities. Moreover, the subjects exhibited better stress coping ability and heart rate stability in response to green landscape image stimuli under illuminated conditions, according to their HRV. Conclusion: These results suggest that lower color temperatures and illumination levels alleviate tension, and that viewing green landscape image stimuli at low illumination, or in darkness, is effective for reducing stress. Conversely, high illumination levels and color temperatures are likely to increase tension and stress in response to traffic congestion image stimuli.