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To find evidence of autonomic imbalance and present the heart rate variability (HRV) parameters that reflect the severity of paroxysmal sympathetic hyperactivity (PSH) in children with acquired brain injury (ABI).
Thirteen children with ABI were enrolled and age- and sex-matched children with cerebral palsy were selected as the control group (n=13). The following HRV parameters were calculated: time-domain indices including the mean heart rate, standard deviation of all average R-R intervals (SDNN), root mean square of the successive differences (RMSSD), physical stress index (PSI), approximate entropy (ApEn); successive R-R interval difference (SRD), and frequency domain indices including total power (TP), high frequency (HF), low frequency (LF), normalized HF, normalized LF, and LF/HF ratio.
There were significant differences between the ABI and control groups in the mean heart rate, RMSSD, PSI and all indices of the frequency domain analysis. The mean heart rate, PSI, normalized LF, and LF/HF ratio increased in the ABI group. The presence of PSH symptoms in the ABI group demonstrated a statistically significant decline of the SDNN, TP, ln TP.
The differences in the HRV parameters and presence of PSH symptoms are noted among ABI children compared to an age- and sex-matched control group with cerebral palsy. Within the ABI group, the presence of PSH symptoms influenced the parameters of HRV such as SDNN, TP and ln TP.
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To determine whether heart rate recovery (HRR) following an exercise tolerance test (ETT) is correlated with a changing ratio of peak oxygen consumption (VO2) and maximal metabolic equivalents (METmax).
A total of 60 acute myocardial infarction (AMI) patients who underwent ETT at both assessment points - 3 weeks (T0) after the AMI attack and 3 months after T0 (T1) were included. After achieving a peak workload, the treadmill was stopped with a 5-minute cooldown period, and the patients recovered in a comfortable and relaxed seated position. HRR was defined as the difference between the maximal heart rate (HRmax) and the HR measured at specific time intervals - immediately after the cool down period (HRR-0) and 3 minutes after the completion of the ETT (HRR-3).
HRR-0 and HRR-3 increased over time, whereas VO2max and METmax did not show significant changes. There was a positive correlation between HRR at T0 and the exercise capacity at T0. HRR at T0 also showed a positive correlation with the exercise capacity at T1. There was no significant correlation between HRR measured at T0 and the change in the ratio of VO2max and METmax, as calculated by subtracting VO2max and METmax obtained at T0 from those obtained at T1, divided by VO2max at T0 and multiplied by 100.
Post-exercise HRR measured at 3 weeks after the AMI onset can reflect the exercise capacity 3 months after the first ETT. However, it may be difficult to correlate post-exercise HRR at T0 with the degree of increase in cardiopulmonary exercise capacity in patients with AMI.
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To evaluate the accuracy of a smartphone application measuring heart rates (HRs), during an exercise and discussed clinical potential of the smartphone application for cardiac rehabilitation exercise programs.
Patients with heart disease (14 with myocardial infarction, 2 with angina pectoris) were recruited. Exercise protocol was comprised of a resting stage, Bruce stage II, Bruce stage III, and a recovery stage. To measure HR, subjects held smartphone in their hands and put the tip of their index finger on the built-in camera for 1 minute at each exercise stage such as resting stage, Bruce stage II, Bruce stage III, and recovery stage. The smartphones recorded photoplethysmography signal and HR was calculated every heart beat. HR data obtained from the smartphone during the exercise protocol was compared with the HR data obtained from a Holter electrocardiography monitor (control).
In each exercise protocol stage (resting stage, Bruce stage II, Bruce stage III, and the recovery stage), the HR averages obtained from a Holter monitor were 76.40±12.73, 113.09±14.52, 115.64±15.15, and 81.53±13.08 bpm, respectively. The simultaneously measured HR averages obtained from a smartphone were 76.41±12.82, 112.38±15.06, 115.83±15.36, and 81.53±13 bpm, respectively. The intraclass correlation coefficient (95% confidence interval) was 1.00 (1.00–1.00), 0.99 (0.98–0.99), 0.94 (0.83–0.98), and 1.00 (0.99–1.00) in resting stage, Bruce stage II, Bruce stage III, and recovery stage, respectively. There was no statistically significant difference between the HRs measured by either device at each stage (p>0.05).
The accuracy of measured HR from a smartphone was almost overlapped with the measurement from the Holter monitor in resting stage and recovery stage. However, we observed that the measurement error increased as the exercise intensity increased.
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To quantify autonomic dysfunction in fibromyalgia patients compared to healthy controls using heart rate variability (HRV).
Sixteen patients with fibromyalgia and 16 healthy controls were recruited in this case control study. HRV was measured using the time-domain method incorporating the following parameters: total heartbeats, the mean of intervals between consecutive heartbeats (R-R intervals), the standard deviation of normal to normal R-R intervals (SDNN), the square root of the mean squared differences of successive R-R intervals (RMSSD), ratio of SDNN to RMSSD (SDNN/RMSSD), and difference between the longest and shortest R-R interval under different three conditions including normal quiet breathing, rate controlled breathing, and Valsalva maneuver. The severity of autonomic symptoms in the group of patients with fibromyalgia was measured by Composite Autonomic Symptom Scale 31 (COMPASS 31). Then we analyzed the difference between the fibromyalgia and control groups and the correlation between the COMPASS 31 and aforementioned HRV parameters in the study groups.
Patients with fibromyalgia had significantly higher SDNN/RMSSD values under both normal quiet breathing and rate controlled breathing compared to controls. Differences between the longest and shortest R-R interval under Valsalva maneuver were also significantly lower in patients with fibromyalgia than in controls. COMPASS 31 score was negatively correlated with SDNN/RMSSD values under rate controlled breathing.
SDNN/RMSSD is a valuable parameter for autonomic nervous system function and can be used to quantify subjective autonomic symptoms in patients with fibromyalgia.
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To evaluate the cardiovascular response during head-out water immersion, underwater treadmill gait, and land treadmill gait in stroke patients.
Ten stroke patients were recruited for underwater and land treadmill gait sessions. Each session was 40 minutes long; 5 minutes for standing rest on land, 5 minutes for standing rest in water or on treadmill, 20 minutes for treadmill walking in water or on land, 5 minutes for standing rest in water or on treadmill, and 5 minutes for standing rest on land. Blood pressure (BP) and heart rate (HR) were measured during each session. In order to estimate the cardiovascular workload and myocardial oxygen demand, the rate pressure product (RPP) value was calculated by multiplying systolic BP (SBP) by HR.
SBP, DBP, mean BP (mBP), and RPP decreased significantly after water immersion, but HR was unchanged. During underwater and land treadmill gait, SBP, mBP, DBP, RPP, and HR increased. However, the mean maximum increases in BP, HR and RPP of underwater treadmill walking were significantly lower than that of land treadmill walking.
Stroke patients showed different cardiovascular responses during water immersion and underwater gait as opposed to standing and treadmill-walking on land. Water immersion and aquatic treadmill gait may reduce the workload of the cardiovascular system. This study suggested that underwater treadmill may be a safe and useful option for cardiovascular fitness and early ambulation in stroke rehabilitation.
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Objective: The purpose of this study was to examine the change of heart rate, mean arterial pressure, respiration rate, and spasticity at passive leg range of motion exercise for one month in hemiplegic patients.
Method: Subjects were composed of twenty hemiplegic patients who had spasticity above two grade in modified Ashworth scale. Passive leg range of motion exercise was performed with passive cycle leg exerciser (Autocybex) at the speed of 40 rpm. Training program consisted of two sessions a day, and each session was done for twenty minutes. The heart rate, mean arterial pressure, and respiration rate were checked for each subject before and after passive leg range of motion exercise at initial state and after one month. Spasticity was measured at knee joint of the affected side at initial state and after one month.
Results: The resting heart rate, mean arterial pressure and respiration rate were significantly decreased after one month (p＜0.05). The changes of heart rate, mean arterial pressure, and respiration rate after passive leg range of motion exercise were significantly decreased after one month (p＜0.05). The grade of spasticity was decreased after one month (p＜0.05).
Conclusion: We concluded that passive leg range of motion exercise during one month stabilized heart rate, mean arterial pressure, and respiration rate, and reduced spasticity.
Objective: To evaluate the autonomic nervous system function in chronic renal failure patients compared to normal control and to assess the effect of dialysis method and underlying diseases such as diabetes mellitus and hypertension, on autonomic nervous system function in chronic renal failure patients.
Method: We checked palm and sole skin temperature with digital thermometer, sympathetic skin responses and heart rate variability in chronic renal failure patients (77 persons) and normal control group (77 persons).
Results: The amplitude of sympathetic skin response (SSR) and heart rate variability (RRIV) of patients group showed statistically significant difference compared to control group (p＜0.05). The diabetic patient group with chronic renal failure showed prolonged latency of SSR in sole but significant differences were shown in amplitude and RRIV (p＜0.05). The hypertensive group with chronic renal failure showed prolonged latency of SSR in both palm and sole (p＜0.05) but the amplitude and RRIV of those didn,t show statistical difference (p＞0.05). CRF without diabetes mellitus and hypertension showed significant difference on amplitude of SSR and RRIV (p＜0.05) but autonomic nervous system function tests showed no difference (p＞0.05) between hemodialysis and peritoneal dialysis groups.
Conclusion: SSR test and RRIV could be valuable measure to evaluate autonomic nervous system functions in the patients with chronic renal failure.
Objective: The purpose of this study was to investigate the changes of oxygen consumption and heart rate at forward and backward treadmill walking in healthy male college students.
Method: Subjects were composed of twenty healthy male college students. The oxygen consumption, oxygen consumption ratio of maximal oxygen consumption (VO2max%) and heart rate, heart rate ratio of maximal heart rate (HRmax%) were measured for each subjects by administering a treadmill exercise test at 5 km/hr speed of forward and backward walking. Paired t-test was used to evaluate the difference of the forward and backward walking.
Results: The study showed that heart rate and HRmax% were 120.9 beat/min, 61.6% in forward walking, and 166.1 beats/min, 84.3% in backward walking, respectively. The oxygen consumption and VO2max% were 15.9 ml/kg/min, 37.3% in forward walking, and 23.6 ml/kg/min, 55.8% in backward walking, respectively.
Conclusion: We concluded that 5 km/hr backward walking was more effective exercise program than forward walking to promote health in the college students.
Objective: To investigate the autonomic activities in spinal cord injured patients, and to compare their activities according to the level and completeness of spinal cord lesions.
Method: Thirty-five spinal cord injured patients and thirty healthy adults participated in this study. The ECG signals were recorded at the tilt angle of 0o and 70o for 5 minutes, and power spectral analysis of Heart Rate Variability (HRV) was done at each angle.
Results: The data reveals two major components such as a low-frequency (LF) component (0.05∼0.15 Hz) reflecting primarily sympathetic activities with orthostatic stress, and a high- frequency (HF) component (0.2∼0.3 Hz) reflecting parasympathetic activity. In supine position, all frequency components were not significantly different regardless the level and completeness of spinal cord lesion. At 70o head-up tilt position, the LF power and heart rate didn't increase in complete tetraplegia but significantly increased in paraplegia and healthy adults (p＜0.05). However, the HF power didn't reveal any differences in four groups by decreasing significantly in all groups.
Conclusion: We concluded that there is an abnormal control of autonomic activities especially the sympathetic function in complete tetraiplegia, compared with paraplegia and healthy adults.
Objective: To compare the change of oxygen consumption and heart rate between walking and running at the same condition of treadmill in healthy male college students.
Method: Twenty healthy male college students completed steady-state treadmill test at 3 mph and 5 mph, separately, by walking and running. During the each 6 minutes treadmill test, oxygen consumption (VO2), heart rate (H.R), oxygen consumption ratio of maximal oxygen consumption (% VO2max), and heart rate ratio of maximal heart rate (% HR) were measured each minute.
Results: The showed that mean heart rate were 123.40⁑4.62 beats/min and oxygen consumption were 12.84⁑1.94 ml/kg/min, in 3 mph walking. The mean heart rate were 139.90⁑6.80 beats/min and oxygen consumption were 16.51⁑1.78 ml/kg/min in 5 mph walking. The running showed that mean heart rate were 187.55⁑6.74 beats/min and oxygen consumption were 26.45⁑3.11 ml/kg/min in 3 mph walking. The mean heart rate were 168.45⁑13.34 beats/min and oxygen consumption were 21.05⁑2.00 ml/kg/min in 5 mph walking. There were significant differences (p＜0.05) in mean heart rate, VO2 between the 3 mph walking and running, the 5 mph walking and running.
Conclusion: We concluded that 3 mph walking and running and 5 mph running were an effective exercise to promote health in healthy college students.
Objective: The aims of this study were to know the effects of long time bed immobilization on the heart rate variability and to know the correlation between the heart rate variability and other anthropometric parameters.
Method: The subjects of this study were 60 normal sedentary persons as control group and 22 patients who had been immobilized for a long time because of musculoskeletal problems without any systemic diseases. The heart rate variabilities were measured through the R-R interval variation at rest, deep breathing and valsalva maneuver. These values were compared between control and patient group and were analysed for correlation with age, weight, height, body mass index (BMI), amounts of smoking (pack years), spans of immobilization and physical activity scale (PAS).
Results: The mean heart rate variability of patients were 0.132⁑0.072, 0.216⁑0.109, and 0.289⁑0.171 in rest, deep breathing and valsalva maneuver respectively which were lower than the corresponding 0.176⁑0.085, 0.314⁑0.146, and 0.322⁑0.174 of normal control group. The heart rate variabilities were negatively correlated with age, BMI and amounts of smoking but positively correlated with the height. The physical activity scale of preimmobilization state was negatively correlated with resting heart rate variability but was positively correlated with heart rate variability during deep breathing and valsalva maneuvering state.
Conclusion: The long bed immobilization significantly decreased the heart rate variability and the heart rate variability could be used as a useful tool to measure the effects of immobilization on the heart.
Objective: To investigate the torque curves and heart rate responses to isometric, eccentric and concentric isokinetic exercises with a maximal voluntary contraction of the right knee and elbow joints in 30 healthy men(26.6⁑2.2 years).
Method: Subjected performed the eccentric and concentric isokinetic exercises with 10 repetitions at 60o/sec, while performing the isometric exercises at a joint angle of 60 degrees for the same period of time with Cybex 6000. Peak torque, angle of peak torque, and total work were measured and the flexor-to-extensor ratios of peak torque were calculated.
Heart rates were recorded simultaneously at rest and immediately after the exercise, and the time required to return to the resting heart rate level was also recorded for each exercise session.
Results: Peak torque and total work for the eccentric exercise were significantly higher than those for the concentric exercise(p＜0.01) of the knee and elbow joints. Eccentric peak torques for flexors and extensors of the knee joint occurred at a significantly longer muscle length than the concentric peak torques(p＜0.01).
Flexor-to-extensor ratios of a peak torque of the knee joint between the eccentric and concentric isokinetic exercises did not show a significant difference.
Torques at a joint angle of 60 degrees were highest in the eccentric isokinetic exercise, followed in the order by isometric, and then concentric isokinetic exercises of the knee joint(p＜0.01), and concentric torque at a joint angle of 60 degrees was significantly lower than those of the eccentric and isometric exercises of the elbow joint.
The increase in heart rate and the time of returning to the resting heart rate level were independent of the size of the contracting muscle mass and the types of exercise. The increment ratio for the heart rate was 70.4⁑23.6%.
Conclusion: In conclusion, the response of heart rate to the exercise is not influenced by the contracting muscle mass or the types of exercise in a short duration of maximal voluntary contraction, implying that special precautionary measures are not required for the isometric, eccentric and concentric isokinetic exercises.
Objective: To evaluate the effects of orthostatic stress with a head-up tilt on the autonomic nervous system and to determine how a cerebral stroke influences the cardiac autonomic function, using the power spectral analysis(PSA) of heart rate variability(HRV).
Method: We studied 11 stroke patients with a left hemiplegia and 14 patients with a right hemiplegia. Their hemispheric brain lesions were confirmed by the MRI. The ECG and respiration signals were recorded at the tilt angle of 0o and 70o for 5 minutes under the condition of frequency controlled respirtaion(0.25 Hz). Data were compared with the age- and sex-matched 12 healthy controls.
Result: In a control group, the normalized high frequency power showed a significant decrease during the head-up tilt(p＜0.05), whereas the normalized low frequency power showed a significant increase(p＜0.05). But for the left and right hemiplegia groups, there were no significant changes of normalized high and low frequency power under the orthostatic stress(p＞0.05). Compared with the right hemiplegia and control groups, the left hemiplegia group was associated more with a reduced low and high frequency power and showed no significant changes under the orthostatic stress.
Conclusion: PSA of HRV can identify the reduced cardiac autonomic activity in stroke patients, with a greater reduction in the left hemiplegia group than in the right hemiplegia group, which may cause a high risk of cardiac arrhythmias and sudden death.
Isometric contractions of muscles in upper extremities occur frequently during ordinary daily activities. The isometric handgrip exercise can be one of the best methods for the evaluation and treatment of patients with disability of upper extremity. However these isometric contractions can impose sudden and significant high stresses to the cardiovascular system.
The purpose of this study was to document the torque patterns and cardiovascular responses of subjects by the isometric handgrip exercises and hopefully to provide a guidance for the safe evaluations and prescriptions of isometric exercises.
Eighty healthy male subjects from 21 to 60 years of age performed isometric handgrip exercises using a Baltimore therapeutic equipment work simulator. The peak torque, time to peak torque, and torque at each second were measured by a six-second isometric strength trial program. The blood pressure and heart rate were measured simultaneously at rest and at each minute during isometric exercises at 30%, 50%, and 70% of the peak torque.
There were no differences in the peak torque, time to peak torque, and torque at each second between age groups(p＞0.05). After the onset of peak torque, the torque gradually decreased and recorded 72.8% of the peak torque at 6 seconds.
The mean arterial pressure and heart rate increased significantly during exercise(p＜0.001), but returned to the resting state immediately when the exercise stopped. The mean arterial pressures were significantly different when the duration of exercise prolonged at 50% and 70% of the peak torque(p＜0.05). And also the mean arterial pressures increased significantly when the strength of exercise increased as well(p＜0.001).
We have concluded that attentions should be given to patient's cardiovascular state, and duration and strengh of exercise when the isometric handgrip exercises are prescribed for the evaluation and treatment of patients.
The powers of the low-frequency(LF) and high-frequency(HF) components characterizing heart rate variability (HRV) appear to reflect, in their reciprocal relationship, changes in the state of the sympatho-vagal balance occurring during orthostatic stress with head-up tilt.
We studied 24 healthy volunteers (median age, 23.1 years) who were subjected after a rest period to a series of passive head-up tilt steps chosen from the following angles: 00. 150, 300, 450, 700, and 900 under the condition of frequency controlled respiration(0.25Hz) in order to get data of the Korean young adults.
During head-up tilt, heart rate and normalized low frequency power(LFN : 0.05∼0.15 Hz) of HRV showed significant increase(p=0.000), but normalized high frequency power(HFN : 0.2∼0.3 Hz) and total power showed progressive decrease(p=0.000, p＜0.01 respectively). Male showed significantly higher LFN and lower HFN than female at tilt table angle 00(p＜0.01).
Power spectral analysis of HRV appears to be capable of providing a noninvasive quantitatibve evaluation of graded changes in the state of the sympatho-vagal balance.
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