ABSTRACT
Endurance exercises, such as cycling or running, are useful for reducing arterial stiffness. However, individuals with a low physical fitness level, or patients suffering from leg diseases with pain, are unable to perform such moderate-intensity lower-limb exercises for long periods of time. The aim of this study was to evaluate the effects of acute cycling with Electrical muscle stimulation (EMS) on the brachial to ankle pulse wave velocity (ba-PWV). Ten healthy adult men performed 3 sessions, as follows of 20 min: cycling at 50% VO2max (C), cycling at an intensity of 50%VO2max subtracted from VO2 during EMS (LC), and cycling at the intensity of the LC trial while also being combined with EMS (LC+E). The ba-PWV was measured before and after each exercise. In addition, the femoral artery blood flow (BF) was measured in eight healthy adult men before and after exercise using an ultrasound imaging system. In the C and LC+E trials, the ba-PWV significantly decreased immediately after the exercise session, whereas the ba-PWV did not significantly change following the LC trial in any session. Compared with the baseline, the femoral artery BF values significantly increased after all trials. In the C and LC+E trials, the femoral artery BF was significantly greater than that in the LC trial. Acute endurance low-intensity cycling with EMS results in a reduction in the arterial stiffness which is similar to that with moderate-intensity exercise.
ABSTRACT
Heat-not-burn (HNB) tobacco smoking has spread throughout the market. While it is suggested that HNB tobacco smoking reduces the vascular endothelial function and is associated with a high risk of developing cardiovascular disease. The antioxidant of vitamin C may attenuate the unfavorable effects of HNB tobacco smoking. In the present study, we examined the effect of oral vitamin C ingestion on the flow-mediated dilation (FMD) at the brachial artery and oxidative stress markers in patients before and after transient HNB tobacco smoking. Twelve healthy adult males underwent high-resolution ultrasonography of the brachial artery and evaluations of reactive oxygen metabolites (d-ROMs) and the biological antioxidant potential (BAP) before and after a single session of HNB smoking. FMD was used to examine the endothelial function and the oxidative stress and antioxidant status were determined by using a FRES4 analyzer. In this randomized, crossover, controlled trial, measurements were performed on 2 different days 20 min after the oral administration of 1000 mg of ascorbic acid (VC trial) or a placebo (P trial). Although the FMD values decreased after a single HNB smoking session in both trials, the VC trial showed significantly higher values than the P trial at 60 and 120 min after smoking. Whereas the FMD values 120 min after smoking in the P trial were lower compared to the Pre values, there was no difference in the VC trial. These results suggested that the ingestion of vitamin C might suppress the decrease in the endothelial function caused by a single HNB smoking.
ABSTRACT
As well as active smoking, passive smoking is associated with a high risk of developing cardiovascular disease. The antioxidant vitamin C may inhibit the unfavorable effects of passive smoking. In this study, we investigated the effects of vitamin C ingestion on changes in the flow-mediated dilatation (FMD) at the brachial artery in patients exposed to transient passive smoking. The study participants included seven healthy adult males who were examined by high-resolution ultrasonography of the brachial artery before and after 15-minute of passive smoking. FMD was used to examine the endothelial function. Randomized crossover controlled trial, measurements were performed on two different days 120-minute after the oral administration of 1000mg of ascorbic acid (VC trial) or a placebo (P trial). Although the FMD values decreased after passive smoking in both trials, the FMD values of the VC trial were higher than those of the P trial, with significant differences between the trials observed immediately and 30-minute after passive smoking. The results of this study suggested that the ingestion of vitamin C may suppress the decrease in the vascular endothelial function caused by transient passive smoking.
ABSTRACT
High-intensity interval exercise leads to greater improvements in the vascular endothelial function than continuous exercise at moderate intensity. However, few studies have been performed on the effects of repetition exercise consisting of high-intensity exercise followed by complete rest on the arterial function. Therefore, the purpose of this study was to investigate the effects of repetition exercise on the vascular endothelial function determined by flow-mediated vasodilation (FMD). Eleven healthy male subjects completed two exercise sessions on a cycle ergometer in a counterbalanced order. The exercise sessions were 20 min cycling at 50% maximal work rate (Wmax) (continuous exercise, CE) and 20 × 20-sec intervals at 100%Wmax interspersed with 40-sec intervals at complete rest (repetition exercise, RE). Before and after each protocol, the brachial systolic and diastolic blood pressure were measured in the supine position. Relative FMD was assessed at rest and 30 and 60 min after each exercise regimen, and then the normalized FMD (nFMD) was calculated from the peak shear rate. The FMD significantly increased 30 min after RE (8.2 ± 1.5% to 11.5 ± 3.1%, p<0.01) and non-significantly increased 30 min after CE (7.5 ± 1.6% to 8.1 ± 2.1%, n.s.) before returning to baseline at 60 min after both exercise regimens. The FMD value at 30 min after RE was significantly greater than that at 30 min after CE (p<0.01). The nFMD (a.u.) significantly increased 30 min after RE (1.38 ± 0.64 to 2.00 ± 0.94, p<0.05) and non-significantly increased 30 min after CE (1.20 ± 0.54 to 1.49 ± 0.57, n.s.) before returning to baseline at 60 min after both exercise regimens. These results suggest that repetition exercise may lead to an acute improvement in the vascular endothelial function.
ABSTRACT
Endurance exercises such as cycling and running are useful for improving the arterial function and preventing cardiovascular disease (CVD). However, subjects suffering from spinal cord injury (SCI) or lower limb osteoarthritis (OA) cannot perform these kinds of lower limb exercises. Recently, electrical muscle stimulation (EMS) has been shown to be able to increase the muscle strength and blood flow and improve the peripheral circulation. Arm-cranking exercises with EMS may therefore be able to reduce the risk of CVD for patients with SCI and lower OA. However, this point has not been fully clarified. The purpose of this study was to assess the effect of submaximal arm-cranking exercise with EMS on arterial stiffness. Ten healthy young subjects performed submaximal arm-cranking exercise alone (A) and submaximal arm-cranking exercise with EMS (A+E). In the A+E trial, the submaximal arm-cranking exercise was performed at 30%VO2 max for 20 min while EMS was applied to their thigh and calf muscles during the exercise. The brachial-ankle pulse wave velocity (ba-PWV), systolic and diastolic blood pressure (SBP/DBP) and heart rate (HR) were measured before and after each exercise. Immediately after the exercise session, the HR of the subjects in the A+E trial was significantly elevated in comparison to those in the A trial. The SBP and DBP did not differ between the two trials to a statistically significant extent. In the A+E trial, the ba-PWV was significantly reduced immediately after exercise in comparison to the A trial (1082.6 ± 105.9 cm·sec-1 vs. 1191.7 ± 86.7 cm·sec-1, p < 0.05). These findings suggest that arm-cranking exercise with EMS reduces arterial stiffness and might be useful for reducing the risk of CVD.
ABSTRACT
<p>High-intensity interval exercise (IE) leads to greater improvements in the arterial function than continuous exercise at moderate intensity (CE). However, few studies have been performed on the effects of the repetition exercise (RE) on the vascular endothelial function. The purpose of this study was to compare the effects of CE vs. IE vs. RE during aerobic exercise on the vascular endothelial function determined by flow-mediated vasodilation (FMD). Ten healthy male subjects randomly performed 3 trials as follows: CE (20-min cycling at 50%W<sub>max</sub>), IE (10 × 1-min intervals cycling at 75%W<sub>max</sub> interspersed with 1-min intervals cycling at 25%W<sub>max</sub>), and RE (30 × 20-sec intervals cycling at 100%W<sub>max</sub> interspersed with 20-sec intervals at rest). FMD was assessed at rest and 30 and 60 min after each exercise, and then the normalized FMD (nFMD) was calculated from the peak shear rate. The nFMD (a.u.) significant increased 30 min after IE (1.2 ± 0.2 to 3.0 ± 1.0, p<0.05) and increased 30 min after CE (1.0 ± 0.2 to 1.4 ± 0.2, n.s.) and returned to baseline at 60 min after both exercises, while the nFMD decreased 30 min after RE (1.3 ± 0.2 to 1.2 ± 0.1, n.s.) and was sustained at 60 min. The nFMD value at 30 min after IE was significantly greater than that at 30 min after RE (3.0 ± 1.0 versus 1.2 ± 0.1, p<0.05). These results suggest that RE may lead to a less improvement in the vascular endothelial function than CE and IE.</p>
ABSTRACT
<p>Habitual exercise is important for improving or maintaining the arterial function with age. However, the role of functional fitness on arterial stiffness in the elderly is unclear. This study was conducted to examine the relationships between functional fitness and arterial stiffness in elderly woman. Four hundred and seventy-nine elderly woman participated in the present investigation. The systolic/diastolic blood pressure and brachial to ankle pulse wave velocity were obtained in the supine position using an automatic pulse wave form analyzer. Four items of functional fitness (standing/sitting, walking, hand working, and self-care working) were assessed. The measurement variables were calculated for five chronological classifications (60~64, 65~69, 70~74, 75~79 and 80 yrs or over). The four items of functional fitness and brachial to ankle pulse wave velocity increased linearly with age. A multiple stepwise regression analysis revealed that systolic blood pressure (β= 0.366), age (β= 0.225), heart rate (β= 0.188), body mass index (β= -0.102), and standing/sitting (β= 0.098) were independent contributors to brachial to ankle pulse wave velocity, accounting for 29.6% of the variability. The physical function, especially standing/sitting, influences the arterial function in elderly women.</p>
ABSTRACT
Interval training has a beneficial effect for treating the cardiovascular disease. However, it is not clarify the effects of different exercise intensity and duration on arterial function. In the present study, we evaluated the effect of acute short-term high and moderate-intensity interval exercise on pulse wave velocity. Thirteen healthy men were randomly assigned to perform both acute interval exercise (IE; cycling for 24.6 min at 80%VO<sub>2</sub>max and 50%VO<sub>2</sub>max) and acute continuous moderate-intensity exercise (CME; cycling for 30 min at 50%VO<sub>2</sub>max). The IE and CME protocols were designed such that the exercises resulted in the same workload during each session. The brachial systolic and diastolic blood pressure (SBP and DBP), and brachial to ankle pulse wave velocity (baPWV) were obtained in the supine position using an automatic pulse wave form analyzer at pre- and post-exercise. In IE, baPWV at post-exercise decreased significantly compared with pre-exercise value (1181.9±119.2 cm・sec<sup>-1</sup> vs. 1108.4±109.4 cm・sec<sup>-1</sup>, p<0.01). In CME, however, it was not significantly different between pre- and post-exercise values (1173.5±137.1 cm・sec<sup>-1</sup> vs. 1164.8±96.0 cm・sec<sup>-1</sup>, p=ns). No significant differences in SBP and DBP were found both protocols. These results suggest that acute short-term high and moderate-intensity interval exercise was more effective in reducing baPWV compared with acute continuous exercise.
ABSTRACT
The aerobic training reduces the artery stiffness and systolic blood pressure. The anaerobic training such as resistance training, however, is associated with higher artery stiffness. We hypothesized that low-intensity circuit training might improve the large artery stiffness. The purpose of this study was to determine the effects of long-term low-intensity circuit training on artery stiffness in sedentary women. Twenty healthy women divided into two groups (training group and control group). In the training group, subjects asked to perform the resistance exercises consisted of arm curls, bench presses, lateral pull-downs, leg presses and squats 3 days per week for 2 months. They conducted 5 sets at 30% of their 10RM. Aerobic capacity (ventilatory threshold [VT]), muscle strength, resting blood pressure, and arterial stiffness index (brachial-ankle Pulse Wave Velocity [baPWV]) were evaluated before and after training period. After the low-intensity circuit training, work rate at VT was significantly increased (108.6±25.6W to 128.1±24.3W). The baPWV was significantly decreased (988.7±80.5cm · sec<sup>-1</sup> to 895.7±62.6cm · sec<sup>-1</sup>). In control group, however, there were no significant differences during same duration. These results suggested that long-term low-intensity circuit training attenuates the large artery stiffness in healthy women. This kind of exercise may have great potential to lower the risks of circulatory illness in aged men.
ABSTRACT
In order to find the cause behind the difference in the pattern of oxygenation between thigh and calf muscles during an incremental cycling exercise, we investigated the relationship between oxygenation and surface myoelectric activity. Five healthy male subjects performed the five 6-min cycling exercises of 50, 100, 150, 200 and 250 watts. We measured oxygenated hemoglobin/myoglobin (oxy-Hb/Mb) on continuous wave near infrared spectroscopy (NIR) and myoelectric activity with surface electrodes (EMG) . The NIR probe and electrodes were positioned on the vastus lateralis muscle (VL) and lateral gastrocnemius muscle (LG) of the right leg. The relative change in oxy-Hb/Mb was estimated by regarding the oxy-Hb/Mb level in the resting condition as 100% and that obtained during thigh occlusion as 0 %. The mean values of oxy-Hb/Mb and integrated EMG (iEMG) determined ranged from 5'30'' to 6'00'' at each work rate. In the VL, the oxy-Hb/Mb level decreased slightly at 50 and 150 watts (99.2±6.8% and 84.6±12.9%), followed by a more prom-inent decrease at 200 and 250 watts (74.9±11.9 and 65.2±9.6%) . The iEMG increased slowly at 50 and 150 watts (24.9±8.8 and 38.0±8.8μV), and a rapid increment occurred at 200 and 250 watts (49.6±13.0 and 57.3±19.6μV) . In the LG, however, the oxy-Hb/Mb level was decreased slightly at 50 and 200 watts (97.3±11.1 and 87.4±6.4%) and a rapid decrement occurred at 250 watts (74.1±6.0%) . The iEMG increased slowly at 50 and 200 watts (18.3±9.4 and 30.5±8.8 μV), and a rapid increment occurred at 250 watts (38.5±8.9 μV) . There was a significant negative correlation between the oxy-Hb/Mb level and iEMG in the VL (r=-0.587, p<0.001) and in the LG (r=-0.599, p<0.001) . From these results, we speculated that the difference in the relative change of oxy-Hb/Mb between the vastus lateralis and the lateral gastrocnemius muscle was due to the difference of increase pattern of muscle activity accompanied by an increase in exercise intensity in these two muscles.
ABSTRACT
The most characteristic feature of the triathlon is integration of the three endurance activities including of swimming, cycling and running, into a continuous task. So, it is necessary to identify the cardiorespiratory responses during the triathlon to develop a beneficial training program. Twelve male triathletes conducted a simulated triathlon test in a laboratory. This test consisted of continuous swimming, cycling and running using a flumepool, a bicycle ergometer and a treadmill, respectively. The exercise intensity and duration were 60% of maximal oxygen uptake during swimming, cycling and running for 30, 75 and 45 min, respectively. The results demonstrated that the residual effects of the prior exercise stage were observed during the latter exercise stage : The prior swimming stage produced an increment of oxygen uptake and heart rate during the cycling stage ; Prior swimming and cycling stages increased oxygen uptake, minute ventilation, heart rate and ventilatory equivalent to those during the running stage. These results suggest that the residual effects of the preceding exercise decreased the mechanical and respiratory efficiency by increasing the physiological demands of conducting the subsequent exercise. Therefore, triathletes are recommended to train themselves in a continuous task rather than separately.