• Journal of Korean Medicine Rehabilitation
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• v.32 no.1
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• pp.73-87
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• 2022

Objectives We aimed to characterize the results obtained from Korean medical examinations and questionnaires on the quality of sleep. Methods The quality of sleep was measured using the Pittsburgh sleep quality index in 400 subjects. Afterwards, heart rate variability (HRV) measurements were done, along with the analyses for tongue color, teeth marks, and tongue coating through the tongue diagnosis system. A questionnaire about body's heat, cold and sweating conditions, and the perceived stress scale (PSS) were performed. Finally, correlations between all these indicators and the sleep quality were analyzed. Results As the quality of sleep decreased, the sympathetic nervous system was stimulated. The subjects who had the blue-purple colored tongue experienced decreased quality of sleep. The quality of sleep was also deteriorated in the subjects who usually feel cold and hot easily, sweat a lot, and feel a lot of discomfort. According to the PSS questionnaire, the higher the stress level is, the lower was the quality of sleep. Conclusions We obtained meaningful results by comprehensively analyzing the sleep quality, HRV, tongue diagnosis, heat and cold conditions, sweating, and stress conditions. In particular, the sleep quality had a significant correlation with the rest of the indicators.

• Korean Journal of Exercise Nutrition
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• v.23 no.3
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• pp.22-28
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• 2019

[Purpose] The purpose of this study was to investigate the effect of diet plus exercise training and detraining for 12 weeks on body composition, aerobic performance, and stress-related variables in obese women. [Methods] Twenty-five women in their 20s-40s with 30% body fat and body mass indices above 25 kg/m² were divided into HR_LT (heart rate at lactate threshold) and HR_LT + 5% groups. Dietary intervention of 70% recommended dietary allowance (RDA) and exercise treatment composed of aerobic exercises on a bicycle (30 min) and treadmill (30 min) were then performed. These interventions were performed three times a week for 12 weeks. [Results] Dietary intake was significantly decreased, while daily activity significantly increased within the 12-week intervention period, and this effect was sustained after 12 weeks of detraining. Exercise training based on dietary intake and daily activity presented a significantly decreased weight and % body fat, improvement of aerobic performance, and a significant increase in heart rate variability (HRV) (e.g., average of all RR intervals and the square root mean squared differences of successive RR intervals) as stress-related variables. It was also confirmed that the improvement of body composition and stress-related variables were maintained even after detraining. [Conclusion] Our results suggest that 70% RDA of dietary intervention and exercise training corresponding to HR_LT and HR_LT + 5% for 12 weeks were effective in improving body composition and aerobic performance, and relieving stress. In particular, enhanced HRV persisted for up to 12 weeks after the end of exercise training in obese women.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.27-39
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• 2023

Purpose : The aim of this study was to identify the influence of transient isokinetic exercise on cardiac autonomic modulation and muscle properties in healthy male subjects. Methods : Twenty-eight healthy males underwent isokinetic exercise of both knee joints using a Biodex systems 3 isokinetic dynamometer with an angular velocity of 60 °/sec. The changes in activity of the autonomic nervous system, as determined by heart rate variability (HRV), and in muscle properties were evaluated at three times: pre-exercise, immediately post-exercise, and 10 min post-exercise. Results : The time domain analysis of HRV revealed significant changes in the beat count and mean and minimal heart rate (HR) measured at pre-exercise, immediately post-exercise, and 10 min post-exercise (p<.001). The beat count and mean HR were markedly increased immediately post-exercise compared to pre-exercise, but then significantly decreased at 10 min post-exercise (p<.001). All parameters of the frequency domain were significantly altered by isokinetic exercise (p<.01). The low frequency/high frequency (LF/HF) ratio, as an index for the sympathovagal balance, was elevated by exercise and remained at a similarly high level at 10 min post-exercise (p<.01). The muscle properties of rectus femoris were changed as follows: Muscle tone and stiffness were significantly increased between pre-exercise and immediately post-exercise (p<.001), and between pre-exercise and at 10 min post-exercise (p<.001). Whereas, the elasticity showed no significant change. Conclusion : These results demonstrated that transient isokinetic exercise could induce changes in cardiac autonomic control and muscle properties. In particular, up-regulation of LF/HF ratio after exercise signifies thus enhanced sympathetic modulation by isokinetic exercise. Therefore, it is needed to understand the cardiovascular risks that may arise during isokinetic exercise for providing the basic evidence to establish appropriate isokinetic exercise protocols as effective rehabilitation exercises.

• Journal of Digital Policy
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• v.2 no.4
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• pp.25-32
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• 2023

This paper is a study to develop a deep neural network (DNN) blood glucose prediction model based on heart rate (HR) and heart rate variability (HRV) data measured by PPG-based sensors. MLP deep learning consists of an input layer, a hidden layer, and an output layer with 11 independent variables. The learning results of the blood glucose prediction model are MAE=0.3781, MSE=0.8518, and RMSE=0.9229, and the coefficient of determination (R²) is 0.9994. The study was able to verify the feasibility of glycemic control using non-blood vital signs using PPG-based digital devices. In conclusion, a standardized method of acquiring and interpreting PPG-based vital signs, a large data set for deep learning, and a study to demonstrate the accuracy of the method may provide convenience and an alternative method for blood glucose management in dogs.

• The Journal of Internal Korean Medicine
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• v.45 no.4
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• pp.810-822
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• 2024

Objectives: The purpose of this study was to evaluate the effectiveness of Korean medicine treatments in alleviating symptoms of dry mouth, with a specific focus on Yin deficiency. Methods: A 50-year-old female patient diagnosed with xerostomia was treated using Korean medicines, aimed at addressing Yin deficiency. The assessment included both subjective and objective measures. For subjective measures, we used the Yin Deficiency Questionnaire (YDQ) to diagnose and assess the Yin deficiency symptoms and the Dry Mouth Symptom Questionnaire (DMSQ) to evaluate the severity and frequency of dry mouth symptoms. For objective measures, we used the Oral Moisture Checking Device (Mucus®) to measure oral moisture levels. Additionally, we measured the heart rate variability (HRV) to assess the autonomic nervous system, focusing on indicators related to the parasympathetic nervous system. Results: We observed improvements in the patient's symptoms. The Visual Analog Scale (VAS) scores improved for all questions on both DMSQ and YDQ questionnaires. Additionally, the measurements taken with Mucus increased, and the HRV test indicators related to the parasympathetic nervous system showed improvement. Conclusion: Korean medicine treatment could be an effective and quick method for treating dry mouth symptoms.

• Sleep Medicine and Psychophysiology
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• v.21 no.2
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• pp.69-73
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• 2014

Objectives: This study was designed to assess the change of heart rate variability (HRV) at resting, upright, and psychological stress in anxiety disorder patients. Methods: HRV was measured at resting, upright, and psychological stress states in 60 anxiety disorder patients. We used visual analogue scale (VAS) score to assess tension and stress severity. Beck depression inventory (BDI) and state trait anxiety inventories I and II (STAI-I and II) were used to assess depression and anxiety severity. Differences between HRV indices were evaluated using paired t-tests. Gender difference analysis was accomplished with ANCOVA. Results: SDNN (Standard deviation of normal RR intervals) and low frequency/high frequency (LF/HF) were significantly increased, while NN50, pNN50, and normalized HF (nHF) were significantly decreased in the upright position compared to resting state (p < 0.01). SDNN, root mean square of the differences of successive normal to normal intervals, and LF/HF were significantly increased, while nHF was significantly decreased in the psychological stress state compared to resting state (p < 0.01). SDNN, NN50, pNN50 were significantly lower in upright position compared to psychological stress and nVLF, nLF, nHF, and LF/HF showed no significant differences between them. Conclusion: The LF/HF ratio was significantly increased after both physical and psychological stress in anxiety disorder, but did not show a significant difference between these two stresses. Significant differences of SDNN, NN50, and pNN50 without any differences of nVLF, nLF, nHF, and LF/HF between two stresses might suggest that frequency domain analysis is more specific than time domain analysis.

• Sleep Medicine and Psychophysiology
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• v.17 no.1
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• pp.21-27
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• 2010

Objectives: It is well established that primary insomnia affects the activity of autonomic nervous system. We tried to know how the activity of autonomic nervous system during night sleep changes by analyzing correlation between heart rate variability (HRV) index and the variables related with sleep structure in primary insomnia. Methods: Thirty three subjects (mean age: $36.2{\pm}14.2$ years, male:female=15:18) who were diagnosed with primary insomnia were selected for the study. Nocturnal polysomnography (NPSG) was carried out on each subject and correlation was analyzed between high frequency/low frequency ratio (LF/HF ratio), one of HRV indices and the variables related with sleep structure which were calculated from NPSG. Results: When age and sex were controlled, LF/HF ratio showed negative correlations with slow wave sleep and stage 2 sleep, respectively ($r_p$=-0.43, p=0.01; $r_p$=-0.37, p=0.04). On the other hands LF/HF ratio showed a positive correlation with arousal index ($r_p$=0.65, p<0.001). The activity of autonomic nervous system responded differentially depending on the change of sleep structure in primary insomnia. Especially the increase of arousal index and the decrease of slow wave sleep and stage 2 sleep which are the components of non-REM sleep provoked hyperactivity of sympathetic nervous system. Conclusion: This study suggests that the typical change of sleep structure in primary insomnia can negatively impact on cardiovascular system.

• Sleep Medicine and Psychophysiology
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• v.25 no.1
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• pp.15-20
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• 2018

Objectives: This study was designed to assess the change of heart rate variability (HRV) at resting, upright, and psychological stress states in depressive disorder patients. Methods: HRV was measured at resting, upright, and psychological stress states in 62 depressive disorder patients. We used visual analogue scale (VAS) score to assess tension and stress severity. Beck depression inventory (BDI) and state trait anxiety inventories I and II (STAI-I and II) were used to assess depression and anxiety severity, respectively. Differences between HRV indices and VAS score were evaluated using paired t-tests. Gender difference analysis was conducted with ANCOVA. Results: SDNN (standard deviation of normal to normal intervals), LF/HF (low frequency/high frequency), and VLF (very low frequency) were significantly increased, while NN50 and pNN50 were significantly decreased in the upright position compared to resting state. SDNN, RMSSD (root mean square of the differences of successive normal to normal intervals), and VLF were significantly increased, while pNN50 was significantly decreased in the psychological stress state compared to resting state. SDNN, NN50, and pNN50 were significantly lower in an upright position compared to a state of psychological stress, and LF, HF, and LF/HF showed no significant differences Conclusion: The LF/HF ratio was significantly increased after physical stress in depressive disorder. However, the LF/HF ratio was not significantly increased after psychological stress, and the change in LF/HF ratio after physical stress and psychological stress did not significantly differ from each other. Significant increase in SDNN, NN50, and pNN50 in an upright posture compared to psychological stress suggests that depressive patients react more sensitively to physical stress than psychological stress.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.4
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• pp.227-234
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• 2012

In this study, the masking effect of olfactory stimulus on the awakening state due to sound stimuli while driving using Graphic Driving Simulator was observed through the response of autonomic nervous system. The test was conducted for 11 males in their twenties. The siren of ambulance car was presented to them as auditory stimulus for 30 secs while driving in a situation of high way in the condition of both peppermint and control, respectively, and LF/HF ratio of HRV (Heart Rate Variability), the activity index of sympathetic nerve, and GSR (Galvanic Skin Response) response were examined. The test was proceeded in the order of three stages, that is, sound stimuli (test 1), driving performance, and sound stimuli (test 2), and fragrance stimulus, driving performance, and sound stimuli (test 3), and the physiological signal of GSR, HRV was measured in the whole stages. As a result of test, comparing the results of before and after auditory stimulus test (1) (p < 0.01), test (2) (p < 0.05), and test (3) (p < 0.01), driving performance test (2) (p < 0.01), test (3) (p < 0.01), and olfactory stimulus test (3) (p < 0.05), respectively, GSR response increased, showing significant difference in all the tests. It indicates that when auditory stimulus was presented to the subjects, they were in the awakening state as sympathetic nervous system got activated. As a result of comparing auditory stimulus while driving before and after presenting olfactory stimulus, there was no significant difference in GSR response. The LF/HF ratio of HRV increased, showing a significant difference only in test (2) (p < 0.05), and in driving performance test (2) (p < 0.05) in auditory stimulus, however, it showed no significant difference in olfactory stimulus. As a result of comparing auditory stimulus while driving before and after presenting olfactory stimulus, there was a decrease, showing significant difference (p < 0.05) in LF/HF ratio of HRV. That is, it means that the activation of sympathetic nervous system decreased, and that parasympathetic nervous system got activated. From these results, it was observed that while driving, the awakening level due to auditory stimulus was settled with olfactory stimulus. In conclusion, it was drawn that while driving, olfactory stimulus could have the masking effect on auditory stimulus.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.11a
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• pp.154-157
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• 2009

본 논문은 ECG의 긴장과 이완상태를 자동으로 인식하기 위해서 SOM 학습을 이용한다. 기존의 ECG 연구는 자극원의 유무에 따라서 정상상태와 변화상태를 비교하여 데이터를 분석하였다. 본 연구에서는 피험자를 ECG로 측정하여 분석한 후 SOM학습을 이용해서 자동으로 긴장과 이완상태를 분석한다. 실험은 피험자에게 슈팅게임을 하게 한 후 ECG로 측정한다. SOM 입력벡터는 측정된 ECG의 HRV분석으로 시간분석과 주파수분석의 특징벡터들을 추출한다. 특징이 추출된 입력벡터들은 SOM으로 학습하여 자동으로 피험자의 긴장과 이완상태를 분류하여 인식할 수 있었다. ECG와 SOM학습의 매칭도 결과는 71%의 정확도를 보였다.