식후 운동이 심근 자율신경계에 미치는 영향

이희혁(Hee-Hyuk Lee) 한국생활환경학회 2015 한국생활환경학회지 Vol.22 No.3

This study examined the influences of food intake on cardiac autonomic responses to acute bouts of vigorous exercise, reflected by heart rate variability (HRV). On four occasions, six physically fit and young males exercised, in random order, on a cycle ergometer either before and 30 minute, 60 minute, or 90 minute after food intake (505 kcal), each followed by five min of active recovery. Electrocardiogram data was collected for 5 minute intervals in the sitting position, at rest before and after each exercise bout. Measures of heart rate variability obtained from frequency domain analysis of ECG recording were as follows: the low frequency and high frequency components which were calculated as normalized units and their ratio (LF/HF ratio). Analysis of heart rate variability revealed a significant increase in sympathetic activity and a significant decrease in parasympathetic activity (p<0.05) following the meal. Further HRV variables were associated with higher shifts during exercises at postprandial 30min or 60min, as compared to exercise at 90 min after the meal (p<0.05), These results suggest that exercise when performed in fasting or after 90 min following a meal may be effective in minimizing exercise-induced cardiac sympathovagal imbalance.

비만 중년여성의 12주간 운동프로그램 참여가 심박 변이도에 미치는 영향

이희혁(Hee Hyuk Lee),정일규(Il Gyu Jeong),오명진(Myung Jin Oh),윤상윤(Sang Yoon Yoon),이부용(Bu Yong Lee) 한국사회체육학회 2011 한국사회체육학회지 Vol.0 No.43

Obesity is associated with an increased risk of cardiac complications that may be due to abnormal cardiovascular autonomic function reflected by reduced heart rate variability. We investigated the effect of a 12-wk exercise program on heart rate variability in middle-aged obese women. Ten middle-aged obese female volunteers with age 56.2±9.29y, % body fat 35.5±2.72% and BMI 27.1±2.8㎏/㎡. The training period was 12-wk, including 5~6 sessions/wk at an intensity of 40~70% of heart rate reserve(HRR), lasting for 60min/session. Measures of heart rate variability, obtained from both time-and frequency domain analysis of 5min ECG recording were as follows: mean RR interval and its standard deviation(SDNN), the mean square successive differences(rMMSSD), the low and high frequency components which were calculated as normalized units and their ratio(LF/HF). After the exercise program, body mass index and % body fat decreased to 4.8% and 5.5% respectively, which was accompanied by decrease in resting heart rate. Exercise training increased rMSSD by 54%, HFnu by 6.3% and decreased LFnu by 5.7%, LF/HF ratio by 12% significantly. The 12-wk exercise program led to changes in HRV indicative of an improvement in cardiac autonomic modulation in middle-aged women with obesity.

트레드밀 운동이 청소년기 흰쥐의 기억력과 해마 신경세포생성, BDNF, TrkB, 그리고 전뇌 콜린 세포에 미치는 영향

이희혁(Hee-Hyuk Lee) 한국생명과학회 2009 생명과학회지 Vol.19 No.3

본 연구는 청소년기 흰쥐를 대상으로 4주간의 저강도 트레드밀 운동이 기억력과 해마 신경세포생성, BDNF, Trkb, 중격콜린세포에 미치는 효과를 조사하기 위하여 수행되었다. 먼저 운동이 기억력에 미치는 효과를 step-through avoidance에서 검사한 결과 운동을 실시했던 흰쥐의 retention latency가 대조군에 비해 유의하게 증가되어 기억력 향상을 나타내었다. 이후 기억력 향상기전으로 해마에서 신경세포증식과 BDNF 및 TrkB 단백질 발현을 정량화 한 결과에서도 운동군의 신경세포생성율과 BDNF와 TrkB 단백질 발현 모두 대조군에 비해 유의하게 증가된 것으로 나타났다. 게다가 운동을 통한 전뇌 콜린 세포 수의 증가가 해마 신경세포생성과 BDNF 발현 증가에 기여하는 것으로 나타났다. 이러한 결과는 청소년기 운동이 기억력 향상에 도움이 될 수 있음을 보여주는 것이다. This study investigated the effects of treadmill exercise on memory ability, cell proliferation, BDNF, and TrkB in the hippocampus and forebrain cholinergic cells in adolescent rats. Male Sprague-Dawley rats (4 weeks old) were randomly assigned to the following two groups: the sedentary group (n=10) and the exercise group (n=10). Rats in the exercise group were forced to run on a treadmill for 30 min, five times per week for 4 weeks. The latency of the step-through avoidance task was used in order to evaluate memory ability. Hippocampal brain-derived neurotrophic factor (BDNF) and tropomyosin-related kinase B (TrkB) expression were assessed by Western blotting. Hippocampal cell proliferation and forebrain cholinergic cells were assessed by immunohistochemistry. The present study showed that treadmill running during the adolescent period significantly improved memory capability, increased hippocampal cell proliferation, up-regulated hippocampal BDNF and TrkB expression, and enhanced the number of forebrain cholinergic cells. These results suggest that regular exercise during the adolescent period may enhance memory function.

저항운동 강도가 심장 자율신경계에 미치는 영향

이희혁(Lee, Hee-Hyuk) 한국사회체육학회 2015 한국사회체육학회지 Vol.0 No.61

Cardiac parasympathetic balance is altered after resistance exercise. However, the impact of the intensity of resistance exercise in this response remains unclear. Accordingly, the aim of this study was to analyze the acute effect of resistance exercise intensity on cardiac autonomic modulation by using heart rate variability(HRV). Seven young men performed, in random order, control, 40% of RM, 60% of RM, 80% of RM in bench press to momentary muscular failure respectively. Measures of heart rate variability, obtained from both time- and frequency domain analysis of 5min ECG recording were as follows: standard deviation(SDNN), the mean square successive differences(RMSSD), the low and high frequency components which were calculated as normalized units and their ratio(LF/HF ratio). Analysis of HRV revealed a significant increase in sympathetic activity and a significant decrease in parasympathetic activity following all intensities of the resistance exercises(P<0.05). In comparison of intensities, no significant differences were found in HRV indices. These findings suggest that an acute resistance exercise leading to failure induce similar cardiac parasympathetic modulation regardless of intensity.

근막이완요법(myofascial release)이 Ergometer 운동 후 심박변이도와 대퇴직근 경직도에 미치는 영향

이희혁(Lee, Hee-Hyuk),김성대(Kim, Seong-Dae),정일규(Jeong, Il-Gyu) 한국사회체육학회 2017 한국사회체육학회지 Vol.0 No.67

The purpose of the study is to invastigate the effects of myofascaial release on heart rate variability and stiffness of rectus femoris after ergometer exercise. In a cross-over design, 9 young(22.75±1.89years) healthy males performed two incremental 70% HRR cycling bouts, and the neither 10 min of myofascial release or passive rest. The parameters of heart rate variability were obtained from both time-and frequency domain analysis of 5min ECG recording at rest, immediately after exercise and recovery 10min. Standard deviation of the node to node interval(SDNN) and root mean square of successive differences(RMSSD) and the low and high frequency components were calculated as normalized units. In order to measure the mechanical properties like muscle stiffness and elasticity, MyotonPro(Myoton AS ,Tallinn, Estonia) was applied to muscle belly of rectus femoris muscle at rest, immediately after exercise and recovery 10min. From the Myoton measurement, Five indexes (Frequency, Logarithmic Decrement, Dynamic Stiffness, Creep and Mechanical Stress Relaxation) were obtained. The results are as follows: 1. Analysis of HRV revealed a significant increase in sympathetic activity and a significant decrease in parasympathetic activity following ergometer exercise with no significant difference between both groups. 2. The muscle tension and stiffness increased significantly while the elasticity decreased immediately after exercise while no significant effect of myofascial release on mechanical properties indexes was found during recovery period. The results represent that these application of MR technique might influence personal feeling and none-specific recovery from muscle fatigue without any statistically significant change of muscle mechanical properties and heart rate variability.

스포츠 마사지가 고유수용성 감각에 미치는 영향

이희혁(Hee Hyuk Lee),정일규(Il Gyu Jeong) 한국사회체육학회 2014 한국사회체육학회지 Vol.0 No.55

The purpose of this study was to investigate the effect of sports massage applied to the ankle on joint positionsense in young adults. In a cross-over design, eight young (21.6±0.6years) healthy males were randomlyallocated to either receive massage and a week later act as cotrnols or vice versa. The applied massage consistedof effleurage, friction, compression, tapotemen for 5 mni. In order to assess proprioception, active andpassive ankle joint position sense was measured in two differetn ankle angles (30° and 45° of inversion from maximal passive eversion). Absolute angular error values were measured before and immediately after five min sports massage and control session. The absolute angular error was defined as the absolute difference between the target angle and the subject perceived angle of ankle inversion. Results demonstrated that the absoluteangular error decreased significantly after the massage protocols for ankle in 30° of active inversion and45° of passive inversion (P>0.05). On the other hand, the control condition showed no stastically significantchanges in the pretest and posttest. These findings suggest that a single intervention session of sports massage was effective for producing immediate improvements in ankle joint position sense

근전도(근활성도) 지표에 의해 설정된 등척성운동 강도가 심박변이도에 미치는 영향

이희혁(Lee, Hee-Hyuk),김성대(Kim, Seong-Dae),박종석(Park, Jong-Suk),정일규(Jeong, Il-Gyu) 한국사회체육학회 2017 한국사회체육학회지 Vol.0 No.70

Cardiac parasympathetic balance is altered after isometric execrise. However, the definite response and the cause according to the intensity of isometric exercise in this response remain unclear. Accordingly, the aim of this study is to analyze the acute effect of isometric exercise intensity on cardiac autonomic modulation by using heart rate variability (HRV). Ten young (21.5±1.7year) men performed, in random order, 100%, 80%, and 60% of MVC in isometric knee extension exercise during 10sec/ 3bouts respectively. Measures of heart rate variability obtained from both time-and frequency domain analyiss of 5min ECG recording were as follows : standard deviation (SDNN), the mean square successive differences (RMSSD) and the low & high frequency components. The results are as follows. 1. SDNN in 100%, 80%MVC group was significantly higher than in 60%MVC group immediately after exercise (p<.05). 2. RMSSD in 100%MVC group was significantly higher than in 60%MVC group immediately after exercise (p<.05). 3. Analysis of HRV revealed a significant decrease in sympathetic activity and a significant increase in parasympathetic activity following all intensities of the isometric exercises (p<0.05). 4. LFnu and HFnu indices showed no significant difference among all intensities. These findings suggest that the higher intensity of isometric exercies might cause the greater increase in autonomic nerve system. Similar cardiac parasympathetic modulation can be induced by acute isometric exercise regardless of intensity.

정리운동이 부교감신경 재활성화에 미치는 영향

이희혁(Lee, Hee-Hyuk) 한국체육과학회 2015 한국체육과학회지 Vol.24 No.3

Cardiac autonomic balance is altered after exercise. However the impact of the cool-down exercise in this response remains unclear. Our objective is to assess the influence of cool-down exercise on parasympathetic reactivation following exercise. On four occasions, six young(22.4 ±.9 years) healthy males performed, in random order, sub-maximal cycling bouts, each followed by 10 min of recovery period: sitting complete rest, cool-down pedaling with loadless, cool-down pedaling with 30% of work load, and cool-down pedaling with diminishing loads. Electrocardiogram data were collected during 5 min periods in the sitting position, at rest before exercise then at 10 min following cessation of exercise. Parasympathetic reactivation was assessed from heart rate variability(HRV) indices. HRV analysis was performed to obtain time-domain measures [standard deviation of the node to node intervals(SDNN) and root mean square of successive differences(RMSSD)] and frequency-domain measures [normalized LF and HF power and total power(TP)]. Heart rate following cooling-down exercises was significantly lower than the corresponding heart rate without cool-down exercise(p=.05). Analysis of heart rate variability revealed a significant increase in parasympathetic measures after cool-down exercise, as compared to complete rest without cool-down exercise(p=.05), and there was no significant differences among the three cool-down exercises. These results suggest that cool-down exercise may be effective in enhancing cardiac parasympathetic reactivation following endurance exercise.

저항훈련이 streptozotocin 유도 당뇨쥐의 골격근 GLUT4 및 MCT 단백질 발현에 미치는 영향

이희혁(Hee-Hyuk Lee),윤진환(Jin-Hwan Yoon) 한국생활환경학회 2012 한국생활환경학회지 Vol.19 No.1

Currently, resistance training is recommended as a behavioral intervention to enhance metabolic profile in diabetic patients. In the present study, we investigated the effect of resistance training on glucose transporter4(GLUT4) and monocarboxylate transporter(MCT) expression in skeletal muscle of rats with streptozotocin(STZ)-induced diabetes. Adult male Sprague-Dawley rats were randomly assigned to the following four groups: control group(n = 8), diabetic group(n = 8), diabetic and running group(n = 8), and diabetic and resistance group(n = 8). Diabetes was induced by a single injection of STZ(50 mg/kg body weight). Rats in the exercise groups were made to perform their respective exercise session four times per week for 12 weeks. Western blotting was performed to detect GLUT4 and MCT protein in skeletal muscle. Our data showed that GLUT4 and MCT protein levels was markedly decreased in the diabetic group when compared to the control group. However, both resistance and running training significantly increased GLUT4 and MCT protein in diabetic rats and the amount of these protein expression was similar between both trained groups. These results indicate that resistance training may be useful in alleviating metabolic impairment through the increase in glucose and lactate uptake in diabetic skeletal muscle.

주의집중 적용 방법에 따른 저항운동이 근활성에 미치는 영향

이희혁(Hee-Hyuk Lee) 한국생활환경학회 2021 한국생활환경학회지 Vol.28 No.1

The purpose of this study was to investigate whether it is possible to selectively activate the pectoralis major or triceps brachii muscles according to various (verbal, tactic, and visual) attentional focus instructions during the bench press exercise. Nine young male were familiarized with the procedure and performed a 1-repetition maximum (RM) test in the first session. In the second, participants performed one non-instructed set of 3 repetitions at 60% repetition maximum. Six additional sets of 3 repetitions at 60% RM were randomly performed with verbal instruction set, tactic instruction set, and visual instruction set to isolate the chest muscle and isolate the triceps muscle respectively. Maximum EMG activity normalized to 1-RM for each muscle was averaged over the three repetitions for each set and compared between the instructions. Participants showed significantly higher EMG activity of the pectoralis during verbal, tactic, and visual instruction set, compared to non-instructed set. EMG activity of the triceps muscle was significantly increased by the verbal and the tactic instruction. Our results suggest that tactic and visual instruction as well as verbal instruction seem to be effective for increasing activity of the pectoralis and the triceps during the bench press.