• Journal of Korean Biological Nursing Science
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• v.21 no.3
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• pp.178-187
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• 2019

Purpose: The purpose of this study was to investigate how college students' perceived stress, cognitive stress, and somatization affect their heart rate variability (HRV). Methods: This study is a cross-sectional survey research on 191 university students, registered at the G University. The perceived stress scale (PSS) and cognitive stress response scale, were used to assess level of stress. The somatization symptom scale of the Symptom Check List 90 (SCL-90), was used to assess level of somatization caused by stress. To assess heart rate variability (HRV), we conducted a five-minute test using a pulse wave analyzer, to analyze short-term HRV. Results: The SCL-90 somatization score had relatively high positive correlation (p< .001) with cognitive stress, but low positive correlation (p< .001) with perceived stress. Cognitive stress response had low negative correlation (p< .001) with 1nSDNN and 1nRMSSD among HRV parameters. Perceived stress was not correlated with HRV. Multiple regression analysis showed that variables of perceived stress, cognitive stress, and somatization symptoms, could not explain HRV. By contrast, one of the HRV indicators, 1nSDNN, was affected by age, gender, and aggressive-hostile thought, the latter being a subscale of the cognitive stress response scale. Conclusion: This study suggests that stress evaluation for people in early adulthood will be more effective, if the evaluation examines cognitive stress and heart rate variability.

• Perspectives in Nursing Science
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• v.9 no.1
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• pp.36-44
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• 2012

Purpose: The aim of this study was to examine the effects of a yoga program on perceived stress, stress response and heart rate variability in professionals. Methods: The research design was a quasi-experimental intervention study. The participants were 47 adults with professional jobs consisting of an experimental group with 23 adults and a control group with 24 adults. The duration of the yoga program was eight weeks from July 4 to August 30, 2012. Results: There were significant decreases in the stress response score after the yoga program. No significant changes in perceived stress and heart rate variability were observed between the experimental group and control group. However, there were significant decreases in perceived stress, stress response scale, and heart rate variability for some participants whose stress levels were high. Conclusion: An eight-week-long yoga program could be considered as an intervention to decrease the stress response of professionals even though it might not reduce their perceived stress and heart rate variability. To further analyze the effects of a yoga program in professionals, changes in intervention strength (such as longer periods and frequency) and the development of physiological measures, which would show the co-relationship between perceived stress and physiological response, are necessary in future studies.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.95-101
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• 2018

The objective of this study is to evaluate the liquefaction cyclic shear stress ratio considering the soil uncertainty. In this study, the probabilistic ground response analysis and the cyclic shear stress ratio analysis for the liquefaction potential evaluation are performed considering the soil variability. The statistical properties of input ground parameters were analyzed to investigate the parameters affecting the seismic response analysis. The Probabilistic analysis was carried out by Monte Carlo Simulation method. The ground response analysis was performed considering the soil variability and the probability distribution characteristics of the ground acceleration. The probability distribution of the peak ground acceleration by seismic characteristics was presented. The differences of liquefaction shear stress ratio results according to soil variability were compared and analyzed. The maximum acceleration of the ground by the deterministic method was analyzed to be overestimation of the ground amplification phenomenon. Also, the shear stress ratio was overestimated.

• 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 Korean Medicine Rehabilitation
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• v.20 no.4
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• pp.147-157
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• 2010

Objectives : The study is performed to investigate the influence of psychological stress on neck muscles tone and heart rate variability(HRV). Methods : This study was carried out with the data from stress response index score(SRI), surface electromyography(sEMG) and HRV. First subjects were divided into two group according to the SRI points. Subjects in group A had points of SRI in which lower than 30 points. Subjects in group B had points of SRI in which higher than 30 points. Then we investigated how to difference of the index of sEMG and HRV according to each groups. Results : In this study, the muscle contraction of both upper trapezius muscle in stress group were higher than non-stress group significantly. Complexity, root mean square of successive differences of R-R intervals(RMSSD), standard deviation difference between adjacent normal to normal intervals(SDSD), high frequency oscillation power(Ln(HF)), normalized HF(Norm HF) in stress group were lower than non-stress group significantly and normalized LF(Norm LF) was higher. Conclusions : This results show that the stress was associated with neck muscle condition and autonomic nervous system.

• Journal of Korean Biological Nursing Science
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• v.14 no.4
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• pp.249-257
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• 2012

Purpose: The purpose of this study was to examine the effects of phytoncide aromatherapy on stress, symptoms of stress and heart rate variability among nursing students. Methods: This study is a randomized control-group non-synchronized design. The experimental group (n=31) underwent phytoncide aromatherapy for 2 weeks, while the control group (n=31) received placebo therapy. The data were collected using self-administration questionnaires and measurement of heart rate variability (HRV) and analyzed using SPSS WIN 18.0 program. A p value <.05 was considered statistically significant. Results: Total score of stress, individual score of intrapersonal stress, and score of peripheral manifestations in symptoms of stress in the experimental group were significantly lower than those of the control group. All indices of HRV were significantly different between the two groups. LF norm and LF/HF ratio in the experimental group were significantly lower than those of the control group, and HF norm in the experimental group was significantly higher than that of in the control group. Conclusion: Based on these results, it can be suggested that phytoncide aromatherapy was effective in decreasing stress and peripheral manifestations of stress and changing in HRV among nursing students.

• Speech Sciences
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• v.12 no.4
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• pp.95-112
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• 2005

We investigate Korean learners' speech-timing of English before and after instruction in comparison with native speech, in an attempt to resolve disagreements in the literature as to whether speech-timing is measurable (Lehiste, 1977; Roach, 1982; Dauer, 1983 vs. Low et al., 2000; Yun 2002; Jian, 2004). We measured the pair-wise variability between the adjacent stressed and unstressed syllables within a foot as well as that among adjacent feet in approximately 555 English sentences, which were read by 29 native speakers and 41 Korean learners in the intermediate proficiency level. The results show that in comparison with native American English, Korean learner speech is before instruction significantly (p<.001) smaller for the pair-wise variability between the adjacent stressed and unstressed syllables within a foot; and significantly (p=.01) bigger for the variability among adjacent feet within the utterance. The learner speech after instruction showed significant (p=.01) improvement in the pair-wise variability of syllable sequence toward native speech values. The variability among adjacent feet was progressively smaller for learner speech before and after instruction and for native speech (p=.03). We thus conclude that the speech timing difference between Korean English and American English is measurable in terms of the duration. of stressed and unstressed syllables and that the latter is stress-timed and the former is syllable-timing interfered.

• The Journal of Korean Medicine
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• v.31 no.2
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• pp.114-123
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• 2010

Objectives: This study was performed to investigate the effect of cold stress on heart rate variability and peripheral blood flow by Doppler ultrasound in healthy subjects. Methods: We classified the subjects by their Yin or Yang tendency using a Yin-Yang questionnaire. Cold stress was taken on the left hand of subjects for 10 seconds. Heart rate variability and peripheral blood flow were measured on the right radial artery before and after cold stress. Results: The Yang tendency group showed a significant decrease of heart rate after cold stress which was not seen in the Yin tendency group. The Yang tendency group showed a decrease of LF, total power, and increase of HF after cold stress, while the Yin tendency group showed the opposite. However, there were no statistically significant differences of heart rate variability analysis between the results of the two groups before and after cold stress. Recovery time of blood flow velocity by ultrasound Doppler was significantly different between the Yin and Yang tendency groups after cold stress. Conclusion: These results suggest that people with Yin or Yang tendency may show different responses in the autonomic nervous system. Further modified studies may include the responses to various manipulation techniques in acupuncture treatment and the individual responses according to pattern identification in traditional Korean medicine.

• The Journal of Korean Medicine
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• v.29 no.1
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• pp.134-145
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• 2008

Objectives : This study investigated the relationship between drinking, smoking and stress of workers by analyzing heart rate variability. The subjects were workers in the automobile manufacturing industry. Methods : The subjects consisted of 21,239 and 19,999 industrial workers who had received health examination by Korean oriental medicine and submitted questionnaires about drinking history and smoking history, during 8 months from April to November. The subjects were categorized into drinking history and smoking history. The heart rate variability was measured for five minute at rest using SA-3000P (Medicore) and reported stress severity as stress index, stress resistance and fatigue. We analyzed the relationship between drinking, smoking and stress into frequencies, $x^2$-test using the SPSS Ver. 12.0. Results : Regarding the relationship between drinking and stress index orstress resistance, there was no statistically significant difference, but regarding the relationship between drinking and fatigue, the drinker group had a significantly higher level of fatigue than the non-drinker group. There was a statistically significant difference in stress index, stress resistance and fatigue between the current-smoker group and others. Stress resistance of the current-smoker group had lower levels than the non-smoker group or ex-smokers. On the other hand, stress index and fatigue of the current-smoker group had higher levels than the non-smoker group or ex-smokers. Conclusions : The above results revealed that drinking and smoking could put workers under a lot of stress. Smoking workers were especially apt to be under stress and had difficulty in alleviating stress.

• Journal of Korean Academy of Nursing
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• v.50 no.4
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• pp.631-640
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• 2020

Purpose: This study aimed to examine premenstrual symptoms (PMS) of shift nurses and identify the association between PMS, sleep, and occupational stress. Methods: This study was conducted with a secondary data analysis that used data from the Shift Work Nurse's Health and Turnover study. The participants were 258 nurses who were working in shifts including night shifts. PMS, sleep patterns (sleep time and sleep time variability), sleep quality, and the occupational stress of each participant were measured using the Moos Menstrual Distress Questionnaire, a sleep diary, an actigraph, the Insomnia Severity Index, and the Korean Occupational Stress Scale, respectively. Data were analyzed using SPSS 23 and STATA 15.1 to obtain descriptive statistics, Pearson's correlation coefficients, multiple linear regression with generalized estimating equations (GEE) and Baron and Kenny's mediating analysis. Results: The average PMS score, average sleep time, average sleep time variability, average sleep quality score, and average occupational stress score of the participants was 53.95 ± 40.45, 7.52 ± 0.89 hours, 32.84 ± 8.43%, 12.34 ± 5.95, and 49.89 ± 8.98, respectively. A multiple linear regression analysis with GEE indicated that sleep time variability (B = 0.86, p = .001), and sleep quality (B = 2.36, p < .001) had negative effects on nurses' PMS. We also found that sleep quality had a complete mediating effect in the relationship between occupational stress and PMS. Conclusion: These findings indicate that both sleep time variability and sleep quality are important factors associated with PMS among shift work nurses. To improve shift nurses' PMS status, strategies are urgently needed to decrease sleep time variability and increase sleep quality.