• 대한한의학회지
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• 제37권1호
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• pp.114-124
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• 2016

Objectives: The aim of this study is to find what effects both the posture of sitting and standing and the ratio of inhalation and exhalation (I/E) have on heart rate variability (HRV) Methods: We made two breathing sets with 4:6 or 6:4 ratios of I/E at 0.1 Hz of respiratory frequency and sitting or standing position. There was 20 minute-rest between sets. Each set include 5 minute-3 breathings as follows: 0.1Hz paced breath with sitting, usual breathing with standing and 0.1Hz paced breath with standing. Five minute-usual breathings with sitting as basal lines were exerted before and after these 3 breaths. Electrocardiogram-recording was exerted from 73 healthy participants (37 men and 36 women) who carried out two sets of breathings. Finally, HRV indices were analyzed of 62 participants (32 men and 30 women). Results: In 4:6 maintaining the same posture, SDNN were statistically increased, while mean heart rate(HR) were not changed. In 6:4, mean HR, SDNN were statistically increased. When changed from sitting to standing, in 4:6, SDNN were statistically decreased and mean HR was increased. However, in 6:4 during change of posture, SDNN were also statistically decreased and mean HR was statistically decreased. There was no statistical change of HF during 4:6 or 6:4 ratios of I/E moving from sitting to standing position. Conclusions: For increasing HRV, breathing in low respiratory rate with sitting was recommended regardless of ratio of I/E. In changing from sitting to standing, 4:6 may increase mean HR, and 6:4 may decrease mean HR.

• The Korean Journal of Physiology
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• 제4권1호
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• pp.1-11
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• 1970

Studies on the analysis of walking were performed on 33 male subjects. A prescription of physical exercise (walking at a speed of greater than 6 km/hr for more than one hour daily) for the promotion of individual health is presented on the basis of walking analysis. Presumptions were made that adequate physical exercise does promote health and is beneficial for the healthy life and increases the life span. These presumptions were derived from the numerous experimental literatures. The literatures support indirectly the presumptions. The following results were obtained and prescription of physical exercise is presented. 1. Oxygen uptake in a walking on a treadmill at a speed of 4 km/hr was only 3 times of the resting oxygen uptake. This kind of moderate exercise did not stimulate the cardiopulmonary system adequately. Heart rate at a 4 km/hr walking was 101 beats/min in boys of less than 20 years old and 83 beats/min in adults. Oxygen uptake at a 6 km/hr walking exceeded 4 times of the resting oxygen uptake. It was interpreted that walking at 6 km/hr stimulated the cardiopulmonary system for the promotion of health. Heart rate at this speed was greater than 110 beats/min in boys and greater than 100 beats/min in adults. 2. Heart rates in a walking of 10 km/hr were 172 beats/min in boys, and 143 beats/min in adults, respectively. Maximal heart rates were 185 beats/min in boys, 180 in office clerks, and 168 beats/min in construction site laboreres. 3. The correlation between heart rate and oxygen uptake was high, namely, r>0.95. Subsequently heart rate could be used as a measure of degree of intensity of physical exercise instead of the cumbersome oxygen uptake measurement. 4. The prescription of physical exercise for the promotion of health is: Daily walking for more than one hour at a speed of greater than 6 km/hr. Bodily functions in this daily walking are in boys (body weight, 50 kg): heart rates of 110 beats/min; breathing frequency, 28/min; oxygen uptake, greater than 4 times of the resting uptake; pulmonary ventilation, 351/min; stride, 124 strides/min; cumulative number of strides for one hour, 7,440 strides, and energy expenditure of more than 300 kcal. In adults (body weight, 60 kg) the bodily functions are: heart rates of 100 beats/min, breathing frequency, 28/min; oxygen uptake, greater than 4 times of the resting uptake; Pulmonary ventilation, 301/min; stride, 127 strides/min; cumulative number of strides for one hour, 7,670 strides, and energy expenditure of more than 300 kcal.

• Journal of Korean Neurosurgical Society
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• 제64권6호
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• pp.957-965
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• 2021

Objective : Rapid increase in intracranial pressure (ICP) can result in hypertension, bradycardia and apnea, referred to as the Cushing phenomenon. During decompressive craniectomy (DC), rapid ICP decreases can cause changes in mean atrial blood pressure (mABP) and heart rate (HR), which may be an indicator of intact autoregulation and vasomotor reflex. Methods : A total of 82 patients who underwent DC due to traumatic brain injury (42 cases), hypertensive intracerebral hematoma (19 cases), or major infarction (21 cases) were included in this prospective study. Simultaneous ICP, mABP, and HR changes were monitored in one minute intervals during, prior to and 5-10 minutes following the DC. Results : After DC, the ICP decreased from 38.1±16.3 mmHg to 9.5±14.2 mmHg (p<0.001) and the mABP decreased from 86.4±14.5 mmHg to 72.5±11.4 mmHg (p<0.001). Conversly, overall HR was no significantly changed in HR, which was 100.1±19.7 rate/min prior to DC and 99.7±18.2 rate/min (p=0.848) after DC. Notably when the HR increased after DC, it correlated with a favorable outcome (p<0.001), however mortality was increased (p=0.032) when the HR decreased or remained unchanged. Conclusion : In this study, ICP was decreased in all patients after DC. Changes in HR were an indicator of preserved autoregulation and vasomotor reflex. The clinical outcome was improved in patients with increased HR after DC.

• ETRI Journal
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• 제43권5호
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• pp.881-890
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• 2021

Photoplethysmography (PPG) is a noninvasive technique that can be used to conveniently measure heart rate (HR) and thus obtain relevant health-related information. However, developing an automated PPG system is difficult, because its waveforms are susceptible to motion artifacts and between-patient variation, making its interpretation difficult. We use deep neural network (DNN) filters to mimic the cognitive ability of a human expert who can distinguish the features of PPG altered by noise from various sources. Systolic (S), onset (O), and first derivative peaks (W) are recognized by three different DNN filters. In addition, the boundaries of uninformative regions caused by artifacts are identified by two different filters. The algorithm reliably derives the HR and presents recognition scores for the S, O, and W peaks and artifacts with only a 0.7-s delay. In the evaluation using data from 11 patients obtained from PhysioNet, the algorithm yields 8643 (86.12%) reliable HR measurements from a total of 10 036 heartbeats, including some with uninformative data resulting from arrhythmias and artifacts.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2001년도 추계학술대회 논문집
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• pp.91-95
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• 2001

In this study, we estimated the behavior of the diversity of physiological responses under varied physical environmental factors by measuring variations of heart rate variability (HRV), an index of activity of cardiac autonomic control. Seven healthy young male adults consented and participated in the study. The environmental conditions consisted of thermal, lighting, and acoustic conditions. Two components of HRV were measured. one was the low frequency (LF) component of HRV, which provided a quantitative index of the sympathetic and parasympathetic (vagal) activities controlling the heart rate (HR). The other component measured was the high frequency (HF) component, which provided an index of the vagal tone. The percent contribution of physical environmental factors to the variations in HRV indices were calculated by ANOVA. The contribution of physical environmental factors to the variations in HR was higher than the contribution of HF and LF. However, the contribution of these factors was lower than the contribution related with individual difference in all indices. This result showed that the individual diversity of physiological responses is not a negligible quantity.

• Journal of Nutrition and Health
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• 제38권2호
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• pp.117-124
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• 2005

We investigated the effects of prolonged exposure in hot environmental condition and ingestion of fluid on various physiological variables including plasma glucose, lactate, the rating of perceived exertion (RPE), and heart rate as well as golf putting performance. Six male professional golfers were voluntarily participated in three different putting trials which were separated by seven days of time interval period. Three different putting trials were conducted at either 20℃ or 32℃, or 32℃ + Fluid ingestion. Performing 32℃ + Fluid ingestion trial, all subject ingested sport drink as much as their body mass was decreased. For each experiment, all subjects were undertaken total 48 putting, which separated by four x 12 putting in four different time points (i.e., Rest, 1 hr, 2 hr, and 3 hr). Plasma glucose concentration was significantly decreased with hot ambient condition but it was almost fully recovered by fluid ingestion. Plasma lactate concentration was significantly higher when subjects were exposed in hot environmental condition, and it did not change with fluid ingestion. There was a no different in putting performance and psychological fatigue level (performed by GRID test) at any environmental conditions. The RPE, commonly used for evaluating of physical fatigue level, was significantly dropped by fluid ingestion which indicates lower physical fatigue level. In addition to this, heart rate (HR) was also significantly decreased after fluid ingestion. Based on these results, it was concluded that the ingestion of fluid during prolonged exposure in hot ambient condition decrease the degree of physical fatigue levels and heart rate, which will possibly improve the golf performance when exposed in extreme weather condition in summer. (Korean J Nutrition 38(2): 117～124, 2005)

• Journal of Animal Science and Technology
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• 제63권3호
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• pp.651-661
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• 2021

This study aimed to investigate whether breed, sex, and age affected temperament differently (more or less neophobic) in mature horses during a novel object test. The study included Jeju crossbred (n = 12, age = 9.42 ± 4.57 y), Thoroughbred (n = 15, age = 10.73 ± 3.09 y), and Warmblood horses (n = 12, age = 13.08 ± 3.55 y) with the females (n = 22, age = 11.36 ± 4.24 y) and geldings (n = 17, age = 10.65 ± 3.66 y). Jeju crossbreds (Jeju horse × Thoroughbred) are valuable considering their popular usage in Korea, but limited studies have explored temperament of Jeju crossbred horses. A trained experimenter touched the left side of the neck with a white plastic bag (novel object). The test ended when the horse stopped escape response and heart rate (HR) dropped to baseline. Behavioral score and escape duration were measured as behavioral variables. Multiple variables related to HR and heart rate variability (HRV) were measured to reflect emotional state. These included basal HR (BHR), maximum HR (MHR), delay to reach maximum heart rate (Time to MHR), standard deviation of beat-to-beat intervals (SDNN), root mean square of successive differences (RMSSD), and ratio of low to high frequency components of a continuous series of heartbeats (LF/HF). Statistics revealed that Thoroughbreds had significantly higher behavioral scores, and lower RMSSD than Jeju crossbreds (p < 0.05), suggesting greater excitement and fear to the novel object in Thoroughbreds. None of the behavioral or cardiac parameters exhibited sex differences (p < 0.05). Age was negatively correlated with SDNN and RMSSD (p < 0.05), indicating that older horses felt more anxiety to the novelty than younger horses. Thoroughbreds and females had distinct correlations between behavioral and HRV variables in comparison with other groups (p < 0.05), implying that escape duration might be a good indicator of stress, especially in these two groups. These results are expected to improve equine welfare, safety and utility, by providing insights into the temperament of particular horse groups, to better match reactivity levels with specific functions.

• International Journal of Vascular Biomedical Engineering
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• 제3권1호
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• pp.14-22
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• 2005

In the present study, our aim is to investigate whether responses to the head-up tilt (HUT) on nonlinear properties of heart rate variability (HRV) in young and elderly subjects are different or not. Thirteen young-healthy subjects ($24.5{\pm}3.7$ years) and 18 old-aged healthy subjects ($74.5{\pm}7.4$ years) participated in this study. An electrocardiogram (ECG) in the supine posture, at $0^{\circ}$, and in the standing posture, at $70^{\circ}$ of head-up tilt, was recorded. Detrended fluctuation analysis (DFA) and approximate entropy (ApEn), measures of short-/long-term correlation properties and overall complexity of heart rate (HR) respectively, along with spectral components of HR variability (HRV) were analyzed for both the supine and HUT postures. We observed that the short-term fractal exponent ${\alpha}_1$ increased during HUT posture (F(1, 29) = 39.79, P = 0.000), especially, the young subjects showed a significantly higher values compared to the elderly subjects. ApEn significantly decreased (F(1, 29) = 8.61, P = 0.006) during HUT posture. HUT posture decreased the complexity in HR dynamics and increased short-term fractal exponent values in young subjects but not in elderly subjects. These results imply that there are differences of response to HUT on nonlinear properties between young and elderly subjects.

• 한국실천공학교육학회논문지
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• 제3권2호
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• pp.53-62
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• 2011

공학교육의 좋은 예제로써 ET 운동 시 신체가 반응하는 Respiratory Exchange Ratio (호흡교환률 RER, epm)와 Heart Rate (심장박동률 HR, bpm)의 변화분석이다. 에너지소비량, 운동속도, 그리고 체중감량이 달라질 경우 이에 반응하는 혈관순환계에 대한 Health Training Cardiorespiratory 반응을 통해 호흡교환률(RER)과 심장박동률(HR)의 변화에 대해서 연구되어졌다. 연구결과에 따르면 (1)열소비량이 늘어날수록 호흡교환률(RER)은 지속적으로 일정하게 상승하는 반면 심장박동률(HR)은 서서히 상승하다가 임계점을 지나면 갑자기 크게 증가함을 볼 수 있었다. 그리고 그 임계점이 대략 275 Cal 였다. (2)운동속도가 서서히 증가함에 따라서 RER은 역시 서서히 증가하는 반면 HR은 임계점(약 6.7km/h)까지는 서서히 증가하지만 이후에서는 급격한 증가를 보인다. (3)체중감량이 서서히 증가할 때 (또는, 대사 소비량이 늘어남에 따라서) RER은 역시 서서히 증가하였으나 HR은 체중감량과는 무관함을 보였다.

• 한국전문물리치료학회지
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• 제12권3호
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• pp.74-83
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• 2005

The purpose of this study was to produce the regression equation from non-exercise $VO_{2max}$ of healthy young adults and to develop a maximal oxygen consumption ($VO_{2max}$) regression model. This model was based on heart rate non-exercise predictor variables (rest heart rate, maximal heart rate/rest heart rate), as an extra addition to the general regression which can reflect an individual's inherent or acquired cardiorespiratory fitness. The subjects were 101 healthy young adults aged 19 to 35 years. Exercise testing was measured by using a Balke protocol for treadmill and indirect calorimetry. The prediction equation was analyzed by using stepwise multiple regression procedures. The mean of $VO_{2max}$ was $39.02{\pm}6.72\;m{\ell}/kg/min$ (mean${\pm}$SD). The greatest variable correlated to $VO_{2max}$ was %fat. The predictor variable used in the non-exercise $VO_{2max}$ included %fat, gender, habitual physical activity and $HR_{max}/HR_{rest}$. The non-exercise $VO_{2max}$ estimation was as follows: $VO_{2max}$($m{\ell}/kg/min$)=55.58-.41(%fat)+.59(physical activity rating)-2.69($HR_{max}/HR_{rest}$)-5.36 (male=0, female=1); (R=.85, SEE=3.64, R2=.72: including heart rate variable); $VO_{2max}$($m{\ell}/kg/min$)=48.47-.41(%fat)+.45(physical activity rating)-5.12 (male=0, female=1); (R=.84, SEE=3.74, R2=.70: with the exception of heart rate variable). As an added heart rate variable, there was only a 2% coefficient of determination improved. Therefore, these results demonstrated that heart rate variable correlation with a non-exercise regression model was very low. In conclusion, for healthy young korean adults, those variables that can affect non-exercise $VO_{2max}$ estimation turned out to be only % fat, gender, and physical activity. We suggest that further research of predictor variables for non-exercise $VO_{2max}$ is necessary for different patient groups who cannot perform maximal exercise or submaximal exercise.