Whole-body Periodic Acceleration Research Articles

Non-Invasive Pulsatile Shear Stress Modifies Endothelial Activation; A Narrative Review.

The monolayer of cells that line both the heart and the entire vasculature is the endothelial cell (EC). These cells respond to external and internal signals, producing a wide array of primary or secondary messengers involved in coagulation, vascular tone, inflammation, and cell-to-cell signaling. Endothelial cell activation is the process by which EC changes from a quiescent cell phenotype, which maintains cellular integrity, antithrombotic, and anti-inflammatory properties, to a phenotype that is prothrombotic, pro-inflammatory, and permeable, in addition to repair and leukocyte trafficking at the site of injury or infection. Pathological activation of EC leads to increased vascular permeability, thrombosis, and an uncontrolled inflammatory response that leads to endothelial dysfunction. This pathological activation can be observed during ischemia reperfusion injury (IRI) and sepsis. Shear stress (SS) and pulsatile shear stress (PSS) are produced by mechanical frictional forces of blood flow and contraction of the heart, respectively, and are well-known mechanical signals that affect EC function, morphology, and gene expression. PSS promotes EC homeostasis and cardiovascular health. The archetype of inducing PSS is exercise (i.e., jogging, which introduces pulsations to the body as a function of the foot striking the pavement), or mechanical devices which induce external pulsations to the body (Enhanced External Pulsation (EECP), Whole-body vibration (WBV), and Whole-body periodic acceleration (WBPA aka pGz)). The purpose of this narrative review is to focus on the aforementioned noninvasive methods to increase PSS, review how each of these modify specific diseases that have been shown to induce endothelial activation and microcirculatory dysfunction (Ischemia reperfusion injury-myocardial infarction and cardiac arrest and resuscitation), sepsis, and lipopolysaccharide-induced sepsis syndrome (LPS)), and review current evidence and insight into how each may modify endothelial activation and how these may be beneficial in the acute and chronic setting of endothelial activation and microvascular dysfunction.

Acute Effects of 160-Degree V-Shape Whole-Body Periodic Acceleration (WBPA) on Blood Pressure and Cardiovascular Hemodynamics

Whole-Body Periodic Acceleration (WBPA) has been reported to induce endothelial nitric oxide and cause vasodilation. However, the effects of WBPA on blood pressure and cardiovascular hemodynamics are still unclear and controversial. The objective of this study was to determine whether a single session of 160-degree V-shape Whole-Body Periodic Acceleration (WBPA-V-160), i.e., periodic motion of the supine body headward to footward, improved blood pressure and cardiovascular parameters. A pre-evaluation and post-evaluation of blood pressure and cardiovascular hemodynamics via DynaPulse Noninvasive and Quantitative Hemodynamic Profile Analysis were performed after a single 30 min trial of WBPA-V-160 with a moving distance, headward to footward, of 2 mm, at a constant frequency of 4 Hz. Systolic BP, diastolic BP, heart rate, end systolic pressure, end diastolic pressure, mean arterial BP, and pulse pressure at post-evaluation were significantly lower than at pre-evaluation after WBPA-V-160, whereas systemic vascular compliance and brachial artery distensibility at post-evaluation were significantly higher than at pre-evaluation. The WBPA-V-160, performed for 30 min, did improve blood pressure and cardiovascular hemodynamics by lowing the BP parameters and enhancing systemic vascular compliance.

Cardioprotective Effect of Whole Body Periodic Acceleration in Dystrophic Phenotype mdx Rodent.

Duchenne muscular dystrophy (DMD) is characterized by progressive muscle wasting and the development of a dilated cardiomyopathy (DCM), which is the leading cause of death in DMD patients. Despite knowing the cause of DMD, there are currently no therapies which can prevent or reverse its inevitable progression. We have used whole body periodic acceleration (WBPA) as a novel tool to enhance intracellular constitutive nitric oxide (NO) production. WBPA adds small pulses to the circulation to increase pulsatile shear stress, thereby upregulating endothelial nitric oxide synthase (eNOS) and neuronal nitric oxide synthase (nNOS) and subsequently elevating the production of NO. Myocardial cells from dystrophin-deficient 15-month old mdx mice have contractile deficiency, which is associated with elevated concentrations of diastolic Ca2+ ([Ca2+]d), Na+ ([Na+]d), and reactive oxygen species (ROS), increased cell injury, and decreased cell viability. Treating 12-month old mdx mice with WBPA for 3 months reduced cardiomyocyte [Ca2+]d and [Na+]d overload, decreased ROS production, and upregulated expression of the protein utrophin resulting in increased cell viability, reduced cardiomyocyte damage, and improved contractile function compared to untreated mdx mice.

Abstract 195: Chronic Enhancement of Endogenous Nitric Oxide Production via Whole Body Periodic Acceleration (WBPA) Induces Cardioprotection in 15 Months Diabetic Mice

Background: Diabetes mellitus (DM) is a major risk factor for the development of cardiovascular disease. Over time, diabetic patients develop cardiomyopathy, referred to as diabetic cardiomyopathy (DCM). The etiology of DCM in part relates to the duration of hyperglycemia. We have previously shown that type 1 diabetic mice (T1D) have abnormally elevated cardiomyocyte diastolic [Ca 2+ ] d , sodium ([Na + ] d ) after 3 months of diabetes. Whole body periodic acceleration (WBPA) is the motion of the supine body headward to footward in a sinusoidal fashion to induce pulsatile shear stress, increasing expression and phosphorylation of endothelial-derived nitric oxide synthase (eNOS, p-eNOS). We have previously shown that WBPA decreases [Ca 2+ ] d , sodium ([Na + ] d in various models of cardiomyopathy. We hypothesized that WBPA might reverse ion dyshomeostasis in the long term (15-months) hyperglycemia (glucose>250mg/dl) mice. Methods: 15 C57BL/6J (CONT) and diabetic mice (T1D) were randomized to receive WBPA (480 rpm, 1 hr daily for 20 days). Diastolic [Ca 2+ ] d , ([Na + ] d ) (selective microelectrodes), and ROS production (fluorescent) were determined in isolated cardiomyocytes at day 0 and at upon completion of the treatment (day 20). Results: Hyperglycemia produced an increase in [Ca 2+ ] d , [Na + ] d and ROS production in cardiomyocytes. 20 days of WBPA treatment in established DCM significantly decreased [Ca 2+ ] d , [Na + ] d , and ROS production toward normal values. Conclusions: These findings suggest that WBPA may be a therapeutic strategy to reverse ion dyshomeostasis and oxidative stress in a very established(15mos) DCM

Whole body periodic acceleration in normal and reduced mucociliary clearance of conscious sheep.

The purpose of this investigation was to ascertain whether nitric oxide (NO) released into the circulation by a noninvasive technology called whole body periodic acceleration (WBPA) could increase mucociliary clearance (MCC). It was based on observations by others that nitric oxide donor drugs increase ciliary beat frequency of nasal epithelium without increasing mucociliary clearance. Tracheal mucous velocity (TMV), a reflection of MCC, was measured in sheep after 1-hour treatment of WBPA and repeated after pretreatment with the NO synthase inhibitor, L-NAME to demonstrated action of NO. Aerosolized human neutrophil elastase (HNE) was administered to sheep to suppress TMV as might occur in cystic fibrosis and other inflammatory lung diseases. WBPA increased TMV to a peak of 136% of baseline 1h after intervention, an effect blocked by L-NAME. HNE reduced TMV to 55% of baseline but slowing was reversed by WBPA, protection lost in the presence of L-NAME. NO released into the circulation from eNOS by WBPA can acutely access airway epithelium for improving MCC slowed in cystic fibrosis and other inflammatory lung diseases as a means of enhancing host defense against pathogens.

Effects of Whole Body Periodic Acceleration on Blood Lactate and Recovery Following Maximal Exercise

PURPOSE: Whole-body Periodic Acceleration (WBPA) is a mechanical bed that moves cyclically in a head to foot motion and has been shown to improve blood flow through increasing endothelial-released nitric oxide. This may improve circulation and improve clearance of metabolites. We examined if WBPA may be an effective method of recovery after maximal exercise compared to the gold standard of active recovery following maximal exercise. METHODS: 10 subjects (age 242.2, male n= 6, female n=4), performed a VO2max test using a Bruce protocol and then immediately participated in a recovery protocol using either WBPA or walking (2.0 mph) for 20 minutes. Subjects returned on another day to repeat the VO2max test and perform the other recovery protocol. Outcome measures were blood lactate concentration (BL), heart rate (HR), blood pressure (BP) and oxygen consumption (VO2). These markers were measured at rest, exhaustion, and minutes 1, 4, 7, 10 and 20 of the recovery protocols. Independant t-tests and post hoc Bonferroni were used to compare outcome measures of the recovery protocols. RESULTS: No significant difference was found in BL between recovery protocols. VO2 (ml/kg/min) was significantly lower (P<0.05) for WPBA compared to walking at minutes 4 (8.293.59 vs. 11.273.50), 7 (5.712.88 vs. 9.732.46) and 10 (5.11.68 vs 9.212.60) of recovery. HR was significantly lower (P<0.05) for WBPA vs. walking at minutes 4 (106.59.98 vs 123.2514.76), 7 (103.2511.15 vs. 116.7112.91), 10 (99.7512.57 vs. 118.1414.99) and 20 (94.1312.26 vs. 111.1317.76). CONCLUSION: Our pilot data suggests that WBPA may reduce HR and VO2 faster than walking in the first 10 minutes of maximal exercise recovery.

Effect of Whole-Body Periodic Acceleration on Exercise-Induced Muscle Damage after Eccentric Exercise

To examine the effects of whole-body periodic acceleration (pGz) on exercise-induced-muscle-damage (EIMD) -related symptoms induced by unaccustomed eccentric arm exercise. Seventeen active young men (23.4 ± 4.6 y) made 6 visits to the research facility over a 2-wk period. On day 1, subjects performed a 1-repetition-maximum (1RM) elbow-flexion test and were randomly assigned to the pGz (n = 8) or control group (n = 9). Criterion measurements were taken on day 2, before and immediately after performance of the eccentric-exercise protocol (10 sets, 10 repetitions using 120% 1RM) and after the recovery period. During subsequent sessions (24, 48, 72, and 96 h) these data were collected before pGz or passive recovery. Measurements included isometric strength (maximal voluntary contraction [MVC]), blood markers (creatine kinase, myoglobin, IL-6, TNF-α, TBARS, PGF2α, protein carbonyls, uric acid, and nitrites), soreness, pain, circumference, and range of motion (ROM). Significantly higher MVC values were seen for pGz throughout the recovery period. Within-group differences were seen in myoglobin, IL-6, IL-10, protein carbonyls, soreness, pain, circumference, and ROM showing small negative responses and rapid recovery for the pGz condition. Our results demonstrate that pGz can be an effective tool for the reduction of EIMD and may contribute to the training-adaptation cycle by speeding up the recovery of the body due to its performance-loss-lessening effect.

Acute Effect of Whole-Body Periodic Acceleration on Brachial Flow-Mediated Vasodilatation Assessed by a Novel Semi-Automatic Vessel Chasing UNEXEF18G System

BackgroundRepeated application of whole-body periodic acceleration (WBPA) upregulates endothelial nitric oxide synthase and improves brachial artery endothelial function (BAEF) as assessed by measurement of flow-mediated vasodilatation (FMD). However, the acute effect of a single application of WBPA on BAEF has not been fully characterized. In addition, although a novel semi-automatic vessel chasing system (UNEXEF18G) has now been developed in Japan, the direct comparison of UNEXEF18G with a conventional method for FMD measures has not been conducted even if UNEXEF18G has already been utilized in a relatively large scale study.MethodsWe have developed a novel semi-automatic vessel chasing system (UNEXEF18G) that can measure FMD on-line, identify time to peak vasodilatation (TPV), and determine the area under the vasodilatation curve (AUC). Thus, 45 min of WBPA was applied in 20 healthy volunteers (age, 34 ± 13 years), and BAEF was measured by UNEXEF18G before and after WBPA. Also, UNEXEF18G measured FMD was compared with those of a conventional FMD measurement method at rest in order to validate a novel UNEXEF18G measured FMD.ResultsSingle WBPA resulted in a significant increase in FMD (from 6.4 ± 3.4 to 10.7 ± 4.3%, p < 0.01), a significant decrease in TPV and a significant increase in AUC. In the validation study for UNEXEF18G, Bland and Altman analysis showed that UNEXEF18G measured FMD was almost identical to those of the conventional method at rest.ConclusionThese data suggest the usefulness of a new UNEXEF18G and that single application of WBPA results in acute improvement in BAEF in humans.

Preliminary observations of passive exercise using whole body periodic acceleration on coronary microcirculation and glucose tolerance in patients with type 2 diabetes

BackgroundThe whole body periodic acceleration (WBPA) system was recently developed as a passive exercise device by providing increased pulsatile shear stress for improvement of endothelial function. This study aimed to investigate the acute effects of WBPA on coronary microcirculation and glucose tolerance in patients with type 2 diabetes (T2D). MethodsThe study subjects were 8 patients with T2D who underwent transthoracic Doppler echocardiography for the assessment of coronary flow reserve (CFR) before and immediately after a 45-min session of WBPA. The flow velocity in the distal portion of the left anterior descending coronary artery was measured at baseline and during adenosine infusion. The CFR represented the ratio of hyperemic to basal mean diastolic flow velocity. ResultsWBPA increased CFR from 2.3±0.3 to 2.6±0.4 (p=0.02). WBPA decreased serum insulin level from 26±19μIU/ml to 19±15μIU/ml (p=0.01) and increased total adiponectin from 11.6±7.3μg/ml to 12.5±8.0μg/ml (p=0.02) and high molecular weight adiponectin from 4.9±3.6μg/ml to 5.3±3.9μg/ml (p=0.03), whereas the serum glucose level was stable from 207±66mg/dl to 203±56mg/dl (p=0.8). ConclusionsThis study demonstrates that a single session of WBPA treatment simultaneously improved coronary microcirculation and glucose tolerance in patients with T2D.

Abstract 9481: Whole Body Periodic Acceleration, Novel Passive Exercise Devices, Enhances Blood Supply to Ischemic Hindlimb in Mice and Human

Introduction: Whole body periodic acceleration (WBPA) is a non-invasive, passive exercise device that has been shown to improve endothelial function by increasing shear stress by head-to-foot direction movements of the body. However, the impact of WBPA on blood flow to ischemic legs has not been investigated. Hypothesis: WBPA enhances blood supply in a mouse model of hindlimb ischemia and in patients with peripheral arterial disease (PAD). Methods and Results: After unilateral femoral artery excision, wild type mice were assigned to either the WBPA (n=15) or control (n=13) group. WBPA was applied at 150 cpm for 45 min under anesthesia once a day. WBPA significantly increased blood flow recovery at 7 and 14 days after surgery as determined by laser doppler perfusion imaging. Sections of ischemic adductor muscle stained with anti-CD31 antibody showed a significant increase in capillary density in WBPA-treated mice compared with control mice, suggesting that WBPA promotes angiogenesis at a microcirculatory level. WBPA increased the phosphorylation of endothelial nitric oxide synthase (eNOS) in adductor muscle. The pro-angiogenic effect of WBPA on ischemic limb was blunted in eNOS-deficient mice, suggesting that the stimulatory effects of WBPA on revascularization are eNOS-dependent. Quantitative real-time PCR analysis showed significant increases in molecules involved in angiogenesis, such as VEGF, FGF2, SDF-1, PDGF-B in ischemic hindlimb by WBPA. Protein array analysis showed that WBPA induced changes in the expression profile of serum angiogenesis-related proteins. Facilitated blood flow recovery was observed in a mouse model of diabetes despite no changes in glycemic control. Clinically, 10 patients (age, 69±7 years, 9 men) with PAD underwent single session of WBPA treatment at 140 cpm for 45 min. WBPA significantly improved the ischemic/non-ischemic ratio of blood flow in the lower extremity from 0.74±0.21 to 0.87±0.21 (p&lt;0.05). Conclusions: WBPA increased blood supply to ischemic lower extremities through activation of eNOS signaling and upregulation of pro-angiogenic growth factor in ischemic skeletal muscle. WBPA is a potentially suitable non-invasive intervention to facilitate therapeutic angiogenesis.

Passive Exercise Using Whole-Body Periodic Acceleration Enhances Blood Supply to Ischemic Hindlimb

Whole-body periodic acceleration (WBPA) has been developed as a passive exercise technique to improve endothelial function by increasing shear stress through repetitive movements in spinal axis direction. We investigated the effects of WBPA on blood flow recovery in a mouse model of hindlimb ischemia and in patients with peripheral arterial disease. After unilateral femoral artery excision, mice were assigned to either the WBPA (n=15) or the control (n=13) group. WBPA was applied at 150 cpm for 45 minutes under anesthesia once a day. WBPA significantly increased blood flow recovery after ischemic surgery, as determined by laser Doppler perfusion imaging. Sections of ischemic adductor muscle stained with anti-CD31 antibody showed a significant increase in capillary density in WBPA mice compared with control mice. WBPA increased the phosphorylation of endothelial nitric oxide synthase (eNOS) in skeletal muscle. The proangiogenic effect of WBPA on ischemic limb was blunted in eNOS-deficient mice, suggesting that the stimulatory effects of WBPA on revascularization are eNOS dependent. Quantitative real-time polymerase chain reaction analysis showed significant increases in angiogenic growth factor expression in ischemic hindlimb by WBPA. Facilitated blood flow recovery was observed in a mouse model of diabetes despite there being no changes in glucose tolerance and insulin sensitivity. Furthermore, both a single session and 7-day repeated sessions of WBPA significantly improved blood flow in the lower extremity of patients with peripheral arterial disease. WBPA increased blood supply to ischemic lower extremities through activation of eNOS signaling and upregulation of proangiogenic growth factor in ischemic skeletal muscle. WBPA is a potentially suitable noninvasive intervention to facilitate therapeutic angiogenesis.

Whole Body Periodic Acceleration is a Potential Substitute of Exercise Training of Patients with Risk Factors and Cardiovascular Diseases

Exercise training is beneficial in the primary and secondary prevention and treatment of coronary artrery disease. However, moderate aerobic exercise for at least 30 minutes a day for at least five days is not attainable in patients who are incapable or unwilling to meet these requirements such as those with neurological and rheumatological diseases, and mobility problems. Whole body periodic acceleration (WBPA) with a horizontal motion platform in the direction of the spinal axis through repetitive movements augments intravascular pulsatile shear stress with a release of nitric oxide and improves vascular endothelial function. This device might offer an alternative to active exercise for patients whose medical conditions limit physical activity. In addition, forty-five minutes' WBPA improves the flow reserve of the left anterior descending coronary artery evaluated by transthoracic Doppler echocardiography and insulin resistance in type 2 diabetic patients.Treatment with WBPA for angina patients ameliorates exercise capacity, myocardial ischemia and left ventricular remodeling through central and peripheral effects. In conclusion, WBPA may be a promising treatment tool of patients with endothelial dysfunction, type 2 diabetic patients, and angina patients with old myocardial infarction. The development of such a therapeutic modality will become a substitute of exercise training of patients with risk factors and cardiovascular diseases in the field of cardiac rehabilitation.

Acute Effect of Whole-Body Periodic Acceleration on Heart Rate Variability and Brachial Flow-Mediated Vasodilatation

Whole-body periodic acceleration (WBPA) is reported to up-regulate endothelial nitric oxide (NO) synthase (eNOS) in animal studies and to improve brachial artery endothelial function (BAEF) measured by brachial artery flow-mediated vasodilatation (FMD) in humans. These findings were obtained by repeated application of WBPA. However, single acute effect of WBPA on BAEF in humans is not fully understood. In addition, the effect of WBPA on cardiac autonomic function assessed by heart rate variability (HRV) has not been studied. Thus, we performed 45 min WBPA in 14 healthy volunteers aged 30±10 years old and measured BAEF and HRV before and after WBPA. HRV indices were measured by Holter ECG as LF, HF Mean RR, SDNN, SD index, rMSSD and pNN50. WBPA increased FMD (from 6.4±3.4 to 7.5±3.0%, P<0.01) and increased Mean RR, HF, rMSSD and pNN50. Conclusions: These results suggest that single application of WBPA acutely and effectively improves BAEF and increases cardiac vagal activity. WBPA could ameliorate ischemic arrhythmias in humans.

Conceptual Framework of Collateral-promoting Therapy for Coronary Artery Disease

Human coronary collateral circulation (CCC) serves as an alternative blood-conveying circuit to the ischaemic myocardium. Functional potentiation of CCC is considered as a therapeutic approach in patients with intractable angina for whom revascularisation procedures such as percutaneous coronary intervention and coronary artery bypass graft surgery are not indicated. Augmentation of CCC is established by collateral recruitment and growth. Nitrates and sarpogrelate are representative drugs that enhance collateral recruitment. Exercise, enhanced external counterpulsation and whole-body periodic acceleration accelerate and potentiate collateral growth via increased mechanical stress at pre-existent collateral arterioles. Granulocyte macrophage colony-stimulating factor and heparin favourably modulate the cascade of coronary collateral growth. Further experimental and clinical studies will be needed to create more sophisticated coronary collateral-promoting therapies.

Effect on Treadmill Exercise Capacity, Myocardial Ischemia, and Left Ventricular Function as a Result of Repeated Whole-Body Periodic Acceleration With Heparin Pretreatment in Patients With Angina Pectoris and Mild Left Ventricular Dysfunction

Whole-body periodic acceleration (WBPA) has been developed as a passive exercise device capable of improving endothelial function by applying pulsatile shear stress to vascular endothelium. We hypothesized that treatment with WBPA improves exercise capacity, myocardial ischemia, and left ventricular (LV) function because of increased coronary and peripheral vasodilatory reserves in patients with angina. Twenty-six patients with angina who were not indicated for percutaneous coronary intervention and/or coronary artery bypass grafting were randomly assigned to remain sedentary (sedentary group) or undergo 20 sessions of WBPA with the motion platform for 4 weeks (WBPA group) in addition to conventional medical treatment. WBPA was applied at 2 to 3 Hz and approximately ±2.2 m/s² for 45 minutes. We repeated the symptom-limited treadmill exercise test and adenosine sestamibi myocardial scintigraphy. In the WBPA group, the exercise time until 0.1-mV ST-segment depression increased by 53% (p <0.01) and the double product at 0.1-mV ST-segment depression by 23% (p <0.001). Severity score of myocardial scintigraphy during adenosine infusion decreased from 20 ± 10 to 14 ± 8 (p <0.001) and severity score at rest also decreased from 13 ± 10 to 8 ± 10 (p <0.01). On scintigraphic images at rest, LV end-diastolic volume index decreased by 18% (p <0.01) with an augmentation of LV ejection fraction from 50 ± 16% to 55 ± 16% (p <0.01). In contrast, all studied parameters remained unchanged in the sedentary group. In conclusion, treatment with WBPA for patients with angina ameliorates exercise capacity, myocardial ischemia, and LV function.

“Passive exercise” using whole body periodic acceleration: Effects on coronary microcirculation

The whole body periodic acceleration (WBPA) system has recently been developed as a "passive exercise" device by providing increased pulsatile shear stress for improvement of endothelial function. This study aimed to investigate the short-term effect of WBPA on coronary flow reserve (CFR) through transthoracic Doppler echocardiography (TTDE) in healthy subjects and patients with coronary artery disease (CAD). This study consisted of 15 healthy subjects and 20 patients with CAD who underwent CFR examination before and immediately after WBPA. The flow velocity in the distal portion of the left anterior descending coronary artery (LAD) was measured with TTDE at baseline and during adenosine infusion. Coronary flow reserve was calculated as the ratio of hyperemic to basal mean diastolic flow velocity. The WBPA treatment was completed in all 35 subjects without complications. There were no significant differences in heart rate and systolic blood pressure before and after WBPA. Whole body periodic acceleration increased CFR from 3.3 +/- 1.0 to 3.7 +/- 1.1 in the 35 subjects (P < .001). Coronary angiography showed significant LAD narrowing in 8 of the 20 CAD patients, but WBPA increased CFR from 2.4 +/- 0.4 to 2.7 +/- 0.5 in them as well (P < .01). This study demonstrates that WBPA improves CFR in healthy subjects and patients with CAD.

Whole-Body Periodic Acceleration Enhances Brachial Endothelial Function

Periodic acceleration in the direction of the spinal axis through repetitive movement increases the shear stress on the vascular endothelium. In the present study it was assessed whether whole-body periodic acceleration with a new device would enhance endothelial function in sedentary adult volunteers. Twenty-six sedentary subjects (44+/-3 years) were randomly assigned to remain sedentary or perform exercise training for 4 weeks, followed by crossover. Periodic acceleration was applied with a horizontal motion platform at 2-3 Hz and approximately +/-2.2 m/s2 for 45 min. Increases in the brachial artery diameter were examined at rest, during reactive hyperemia (flow-mediated dilatation: %FMD) and after sublingual administration of 0.3 mg nitroglycerin (%NTG) using high-resolution ultrasound. All subjects completed the study with no adverse side-effects. There were no significant changes in the resting heart rate or arterial pressure, body weight, or lipid profiles during the study. Although %FMD did not change during the non-training period with periodic acceleration, it significantly increased from 7.3+/-0.4% at baseline to 8.4+/-0.4% after the training period (p<0.05), while %NTG remained unchanged. Whole-body periodic acceleration with a horizontal motion platform improved vascular endothelial function in sedentary adults. This device might offer an alternative to active exercise for patients whose medical condition limits physical activity.

Effect of Moderate-Intensity Exercise, Whole-Body Periodic Acceleration, and Passive Cycling on Nitric Oxide Release Into Circulation

To determine if a 3-min bout of moderately intensive supine bicycle exercise, whole-body periodic acceleration (pGz), and passive motorized cycling cause nitric oxide (NO) release into the circulation, as detected by dicrotic notch descent on the diastolic limb of a finger pulse wave. Fourteen healthy adults underwent two levels of supine bicycle ergometry that caused heart rate to rise to 56% (light moderate exercise) and 67% (heavy moderate exercise) of maximum predicted heart rate, and a single bout of pGz. Several months later, 9 of the 14 subjects underwent passive motorized cycling. The ECG and finger pulse wave were recorded. The dicrotic notch position was computed from the amplitude of the digital pulse wave (a) divided by the height of the dicrotic notch above the end-diastolic level (b) and designated the a/b ratio. Increase of the a/b ratio due to dicrotic notch descent reflects the vasodilator action of NO on resistance vessels. The last 30 s of baseline, exercise or pGz, and recovery periods were analyzed. Compared to baseline, light moderate exercise produced a nonsignificant rise of the a/b ratio. Both heavy moderate exercise and pGz produced statistically significant rises of peak and mean a/b ratios over baseline. Heavy moderate exercise produced a greater mean a/b ratio than pGz, but the peak a/b ratio did not differ between the two. Episodic rises and falls of a/b ratios were more common during pGz than exercise. Passive motorized cycling did not alter the a/b ratio. Dicrotic notch descent occurs during a brief bout of moderate cycling exercise, consistent with NO release into circulation. pGz produces comparable descent, but passive motorized cycling does not. In terms of the beneficial effects of NO, this suggests that pGz might serve as a substitute in subjects who are physically incapable of exercising.