• Physical Therapy Rehabilitation Science
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• 제7권2호
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• pp.83-87
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• 2018

Objective: The purpose of this study was to investigate the relationship between heart rate (HR), self-awareness of exercise intensity (rating of perceived exertion, RPE), and 5-meter walk test (5MWT) of persons affected by stroke during backward walking according to the preferred stride frequency (PSF), PSF+3 and PSF+6 conditions. Design: Cross-sectional study. Methods: A total of 11 persons with stroke (9 males, 2 females) participated voluntarily. All patients underwent backward walking under the PSF, PSF+3, and PSF+6 conditions in underwater and ground environments, and each condition was performed for 5 minutes. The HR, RPE, and walking speeds were measured during walking, and the measured values from underwater and ground environments were compared. Results: The HR and RPE in the ground environment were significantly increased (p<0.05), and although the 5MWT showed an increase in speed, it was not significant. The HR and RPE in the underwater environment were also significantly increased (p<0.05), however, although the 5MWT results was increased, it was not significant. The HR and RPE were significantly increased in the PSF+6 condition (p<0.05). Conclusions: The results of this study showed that backward gait training underwater can provide an appropriate exercise intensity for stroke survivors and suggests that exercises performed in an underwater environment is more effective compared to the ground environment.

• 대한불안의학회지
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• 제16권2호
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• pp.83-90
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• 2020

Objective : Heart rate variability (HRV) is known to reflect autonomic nervous system activity. Individuals with posttraumatic stress disorder (PTSD) are reported to have lower HRVs. We attempted to find HRV indices with head up tilt position that reflect the symptoms well in order to evaluate PTSD symptoms. Methods : Sixty-seven patients with PTSD and 72 patients without PTSD were assessed using the PTSD Checklist for DSM-5 (PCL-5), the Beck Depression Inventory, the Beck Anxiety Inventory and the Pittsburgh Sleep Quality Index. HRV was measured in the head-up tilt position. We collected data regarding heart rate (HR), standard deviation of the NN intervals (SDNN), the square root of the mean squared differences of successive NN intervals (RMSSD), log low-frequency (LNLF) and log high-frequency (LNHF). Results : The value of LNHF was different according to presence or absence of PTSD after head-up tilt position. In the findings of the association between PTSD symptoms and HRV indices as based on head-up tilt, LNHF had a significant correlation with the total score of PCL-5. Conclusion : The reduction of the high-frequency component of HRVs in the PTSD group might reflect more PTSD symptoms.

• 대한의용생체공학회:의공학회지
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• 제37권2호
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• pp.61-67
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• 2016

This paper presented a method for random forest based the arrhythmia classification using both heart rate (HR) and heart rate variability (HRV) features. We analyzed the MIT-BIH arrhythmia database which contains half-hour ECG recorded from 48 subjects. This study included not only the linear features but also non-linear features for the improvement of classification performance. We classified abnormal ECG using mean_NN (mean of heart rate), SD1/SD2 (geometrical feature of poincare HRV plot), SE (spectral entropy), pNN100 (percentage of a heart rate longer than 100 ms) affecting accurate classification among combined of linear and nonlinear features. We compared our proposed method with Neural Networks to evaluate the accuracy of the algorithm. When we used the features extracted from the HRV as an input variable for classifier, random forest used only the most contributed variable for classification unlike the neural networks. The characteristics of random forest enable the dimensionality reduction of the input variables, increase a efficiency of classifier and can be obtained faster, 11.1% higher accuracy than the neural networks.

• 대한의용생체공학회:의공학회지
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• 제18권3호
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• pp.285-290
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• 1997

In this paper, the power spectral analysis and the fractal analysis of heart rate variability(HRV) were performed to evaluate the effects of brain lesion on cardiovascular system and autonomic function for 24 normal subjects and 22 hemiplegic patients. The ECG and respiration signals were recorded at tilt angles of $0^{\circ}$ and $70^{\circ}$ for 5 and 6 minutes successively under the condition of frequency controlled respiration (0.25Hz). For normal subjects, HR, LF component, HF component and fractral dimension of HRV were distinctly changed after orthostatic stress, whereas, for hemiplegic patients, those were little changed. Complexity and variability of heart rate of patients were smaller than those of normal subjects. Sympathetic tone of patients was higher than that in normal subjects. All of these results support that autonomic disorder and cardiovascular disturbance accompanied by brain lesion could be assessed by the power spectral analysis and fractal analysis of HRV.

• 생명과학회지
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• 제22권4호
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• pp.532-537
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• 2012

흡연자의 단시간의 흡연 중단이 안정 시 및 저강도(40% of $VO_2max$), 중강도(60% of $VO_2max$)에서의 일회성 유산소성 운동 중에 나타내는 심혈관 반응의 차이를 알아보는데 있다. 따라서 성인 남성 흡연자를 대상으로 흡연 직후, 흡연 중단 24시간과 흡연 중단 48시간 경과 후의 안정 시, 저강도, 중강도의 강도별 사이클 에르고미터를 통한 일회성 유산소 운동 시 심혈관계 반응을 검토하였다. 이에 따른 결과 흡연 직후, 흡연 중단 24시간과 흡연 중단 48시간 경과 후의 안정 시, 저강도, 중강도의 수준의 운동 강도별 사이클 에르고미터를 통한 일회성 유산소 운동 시 SBP, DBP, MAP, HR에서 유의한 감소가 나타났다($p$<0.05). 또한, 안정 시와 중강도에서는 CO의 유의한 감소가 나타났다($p$<0.05). 이상의 결과로부터 단시간의 흡연 중단은 교감신경의 항진상태를 완화시키고, 부교감신경계의 활성화로 인해 HR을 감소시킴으로써 안정 시와 동일 강도 유산소운동 시의 과도한 심혈관 반응을 완화키는 것으로 사료된다. 이를 통해 흡연자에게 있어 단기간의 흡연 금지만으로도 운동 중에 심혈관계 반응의 위험을 감소시킬 수 있다는 가능성을 나타냈다.

• 대한수의학회지
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• 제41권4호
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• pp.597-602
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• 2001

This study was carried out to investigate the effectiveness of active biotelemetry to monitor stress response, and the effects of acute stressor (raising a hind foot of a standing animal) on body temperature (BT) and heart rate (HR) in comparison heifer group (n=4) with cow group (n=3). Both parameters were recorded by active telemetry. Cortisol assay was used to compare the result of active biotelemetry. The stressor consisted in restraining the cows for hoof treatments. Body temperature and heart rate were measured at 0, 10, 20, 30, 40, 50, 60, 90, 120, 180 and 360 minutes during the experiments, and also cortisol assay at 0, 0.5, 1, 2, 3, 12 and 24 hours. Base line for these animals was set in there accustomed environment at -24hrs and -30 mins before the beginning of experiments. The results obtained in this study were as follows: 1. In the BT, heifer group showed no significant difference from cow group, but were observed slightly higher BT than cow group during restraint stress for 30 minutes. 2. The both groups showed directly significant increase of HR immediately after the beginning of the restraint stress (P<0.01), but in the required time for the recovery of HR after finishing the stress, heifer group was 40 minutes and cow group 60 minutes. 3. In the cortisol assay, the both groups increased from 30 to 120 minutes after the beginning of experiment (i.e, from 0 to 90 minutes after finishing the restraint stress), showing significant difference from before the beginning of the stress (P<0.01), but heifer group showed great increase of the cortisol level from 30 to 60 minutes after the beginning of the stress, while cow group was observed at 60 minutes. In conclusion, we suppose that care is required to decrease psychological stress in cattle when they suffer from a series of procedures for diagnosis and treatment, especially in heifers rather than in cows. Also BT and HR obtained by active biotelemetry are reliable indicators of stress in cattle.

• The Journal of Korean Physical Therapy
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• 제31권5호
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• pp.322-327
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• 2019

Purpose: This study examined the influence of the maximal aerobic capacity on the two-year cardiac-related re-hospitalization in patients with heart failure with a reduced ejection fraction (HFrEF) in Korean society. Methods: The maximal aerobic capacity of the study population (n=95, male 63%) was evaluated using a cardiopulmonary exercise (CPX) testing system. Each patient was followed up for two years to divide the HFrEF patients into two groups according to cardiac-related re-hospitalization: re-hospitalization (RH) group (n=29, 30%) and no re-hospitalization (NRH) group (n=66, 70%). Results: The relative peak $VO_2$ (mL/kg/min, p<0.001), exercise duration (p<0.001), respiratory exchange ratio ($VCO_2/VO_2$, p=0.001), systolic blood pressure (SBP) reserve (p=0.004), heart rate (HR) reserve (p=0.007), SBP max (p=0.02), and HR max (p=0.039) were significantly lower in the RH group than the NRH group during the CPX test. On the other hand, the ventilatory efficiency (VE/VCO2 slope, p=0.02) and age (p=0.022) were significantly higher in the RH group than in the NRH group. In binary logistic regression analysis, the relative peak $VO_2$ (p=0.001, Wald Chi-square 10.137) was the strongest predictive factor on cardiac-related re-hospitalization, which was followed by $VCO_2/VO_2$ (p=0.019, Wald Chi-square 5.54). On the other hand, age (p=0.063, Wald Chi-square 3.445) did not have a significant influence on cardiac related re-hospitalization. Conclusion: The maximal aerobic capacity, especially the relative peak $VO_2$, is the strongest factor on cardiac-related re-hospitalization within two years in patients with HFrEF in Korean society.

• 생명과학회지
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• 제13권1호
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• pp.21-28
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• 2003

본 연구의 목적은 10명의 비만여성을 체지방율에 의해 두 그룹(A:30~35%, B:35~40%)으로 분류하여 여러 동일한 속도(5.5, 6.0, 6.5, 7.0km.$hr^{-1}$)에서 걷기와 달리기 시 에너지 소비율과 심박수, 호흡교환율, 근동원량 등을 비교하는 것이었다. 본 실험결과 트레드밀 속도증가에 따른 산소 소비량은 두 그룹모두 걷기시 비선형적으로 증가하는 경향을 나타내었으나, 달리기 시에는 선형적 증가를 나타내어 두 그룹 모두에서 속도 6.5~7km/hr내에서 걷기의 에너지 소비율이 달리기시보다 높아지는 시점을 나타내었다. 두 그룹간 비교에서 유의한 차이는 나타나지 않았으나 A그룹 보다 B그룹이 다소 낮은 속도에서 걷기의 에너지효율성이 달리기시보다 떨어지는 경향을 보였다. 심박 수의 측정결과에서는 체 지방 율이 높은 그룹이 낮은 그룹보다 높은 심박 수 반응을 보여 체 지방 율이 높을수록 운동스트레스가 커지는 결과를 보였다. 호흡교환율 또한 체 지방 율이 낮은 그룹 보다 높은 그룹에서 운동시 탄수화물의 에너지참여비율이 높게 나타나 대사적 스트레스가 높은 것으로 나타났다. 이상의 결과로써 비만여성에서 걷기와 달리기 시 체 지방 율이 높을수록 대사적 스트레스를 증가시킬 수 있는 것으로 나타났고 에너지 소비 율도 영향을 받음으로써 걷기시 에너지 효율성에 비만인간 차이가 발생될 수 있지만, 이러한 차이는 크지 않은 것으로 생각된다.

• 재활복지공학회논문지
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• 제10권4호
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• pp.243-249
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• 2016

본 논문에서는 건강한 성인 26명(남자 14명, 여자 12명)을 대상으로 기계승마의 적용을 통한 심폐기능의 변화 및 그에 따른 운동 강도를 정량적으로 측정하여, 기계식 승마 치료의 임상 적용가능성과 유효성을 추정하였다. 기계승마 장비인 JOBA(R)(Panasonic Electric Works, Osaka, Japan)을 이용하였고, 운동의 강도는 level 2 (0.73 Hz)에서 4 (0.9 Hz), 6 (1.03 Hz), 8 (1.2 Hz), 9 (1.3 Hz)까지 증가시키고, 각각의 level에서 3분간 유지하였다. 운동 중 참여자의 심폐 반응은 호흡가스분석 시스템(TruOne 2400, Parvo Medics, USA)과 운동부하검사 시스템(Q Stress, Cardiac Science, USA)을 이용하여 심박수, 혈압, 최대산소소모량(VO2max)을 측정하였다. 또한 기계승마를 통해 유발되는 유산소 운동 강도를 평가하기 위해 대사당량(MET)을 측정하고, 예비심박수율(%HRR), 최대심박수율(%peak HR)과 칼로리소모량을 계산하였다. 그 결과는 SPSS 18.0 프로그램을 이용해 분석하였으며, 건강한 성인에서 간단한 사전 교육 후 15분간의 JOBA(R)를 이용한 기계식 승마 치료시 증등도의 운동 강도에 도달할 수 있는 것으로 평가되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권2호
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• pp.267-274
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• 2017

Objective: The objective of this study was to investigate the effect of 20-day litter weight on behavior and heart rate variability (HRV) of piglets under stress. Methods: Forty four original litters were categorized as high litter weight (HW) litters (n = 22) and low litter weight (LW) litters (n = 22) by 20-day litter weight. From each original HW litter, three males and three females were randomly selected after weaning and the 12 piglets from two original litters with similar age of days were regrouped into one new high litter weight (NHW) litter (11 NHW litters in total). The original LW litters were treated with a same program, so that there were 11 new low litter weight (NLW) litters as well. The latencies to first fighting, fighting frequencies and duration within three hours were recorded after regrouping and the lesions on body surface within 48 hours were scored. Besides, HR (heart rate, bpm, beats per minute) and activity count (ACT), time domain indexes and frequency domain indexes of the piglets were measured in an isolation trial to analyze the discrepancy in coping with stress between the original HW and LW litters. Results: The results exhibited that piglets from the HW litters launched fighting sooner and got statistically higher skin lesion score than those from the LW litters (p = 0.03 and 0.02, respectively). Regarding the HRV detection, compared with the HW litters, the LW litters exhibited a lower mean HR (p<0.05). In the isolation test, a highly significant higher ACT value was observed between the HW litters, compared to the LW litters (p<0.01). Significant differences were observed in standard deviation of R-R intervals, standard deviation of all normal to normal intervals, and most frequency-domain indicators: very low-frequency, low-frequency, and high frequency between the HW and LW litters as well. The difference in LF:HF was not significant (p = 0.779). Conclusion: This study suggests that compared with litters of low 20-day litter weights, litters with higher 20-day litter weight take more positive strategies to cope with stress and have stronger HRV regulation capacity; HW litters demonstrate better anti-stress and adaptation capacity in the case of regrouping and isolation.