Kazuki Hotta

Low-intensity resistance training with blood flow restriction improves vascular endothelial function and peripheral blood circulation in healthy elderly people

PurposeThe present study aimed to investigate the effects of low-intensity resistance training with blood flow restriction (BFR resistance training) on vascular endothelial function and peripheral blood circulation.MethodsForty healthy elderly volunteers aged 71xa0±xa04xa0years were divided into two training groups. Twenty subjects performed BFR resistance training (BFR group), and the remaining 20 performed ordinary resistance training without BFR. Resistance training was performed at 20xa0% of each estimated one-repetition maximum for 4xa0weeks. We measured lactate (Lac), norepinephrine (NE), vascular endothelial growth factor (VEGF) and growth hormone (GH) before and after the initial resistance training. The reactive hyperemia index (RHI), von Willebrand factor (vWF) and transcutaneous oxygen pressure in the foot (Foot-tcPO2) were assessed before and after the 4-week resistance training period.ResultsLac, NE, VEGF and GH increased significantly from 8.2xa0±xa03.6xa0mg/dL, 619.5xa0±xa0243.7xa0pg/mL, 43.3xa0±xa015.9xa0pg/mL and 0.9xa0±xa00.7xa0ng/mL to 49.2xa0±xa016.1xa0mg/dL, 960.2xa0±xa0373.7xa0pg/mL, 61.6xa0±xa019.5xa0pg/mL and 3.1xa0±xa01.3xa0ng/mL, respectively, in the BFR group (each Pxa0<xa00.01). RHI and Foot-tcPO2 increased significantly from 1.8xa0±xa00.2 and 62.4xa0±xa05.3xa0mmHg to 2.1xa0±xa00.3 and 68.9xa0±xa05.8xa0mmHg, respectively, in the BFR group (each Pxa0<xa00.01). VWF decreased significantly from 175.7xa0±xa020.3 to 156.3xa0±xa038.1xa0% in the BFR group (Pxa0<xa00.05).ConclusionsBFR resistance training improved vascular endothelial function and peripheral blood circulation in healthy elderly people.

Effects of resistance training on muscle strength, exercise capacity, and mobility in middle-aged and elderly patients with coronary artery disease: A meta-analysis

BACKGROUNDnResistance training (RT) is a core component of cardiac rehabilitation. We investigated the effects of RT on exercise capacity, muscle strength, and mobility in middle-aged and elderly patients with coronary artery disease (CAD).nnnMETHODSnWe searched for randomized controlled trials of RT versus usual care, or combined RT and aerobic training (AT) versus AT alone, and identified 440 trials in total from inception to January 2014. Participants who had myocardial infarction, coronary revascularization, angina pectoris or CAD were included in the analysis. Those who had heart failure, heart transplants with either cardiac resynchronization therapy or implantable defibrillators were excluded.nnnRESULTSnTwenty-two trials totaling 1095 participants were analyzed. We performed random-effects meta-analysis. In middle-aged participants, RT increased lower extremity muscle strength [standardized mean difference (SMD): 0.65, 95% confidence interval (CI): 0.35 to 0.95], upper extremity muscle strength (SMD: 0.73, 95% CI: 0.48 to 0.99) and peak oxygen consumption (VO2) [weight mean difference (WMD): 0.92mL/kg/min, 95% CI: 0.12 to 1.72], but did not improve mobility compared with the control. In elderly participants, RT increased lower extremity muscle strength (SMD: 0.63, 95% CI: 0.05 to 1.21), upper extremity muscle strength (SMD: 1.18, 95% CI: 0.56 to 1.80), and peak VO2 (WMD: 0.70mL/kg/min, 95% CI: 0.03 to 1.37), and improved mobility (SMD: 0.61, 95% CI: 0.21 to 1.01) compared with the control.nnnCONCLUSIONSnResistance training could increase exercise capacity and muscle strength in middle-aged and elderly patients, and mobility in elderly patients, with CAD.

Exercise training reverses age‐induced diastolic dysfunction and restores coronary microvascular function

In a rat model of ageing that is free of atherosclerosis or hypertension, E/A, a diagnostic measure of diastolic filling, decreases, and isovolumic relaxation time increases, indicating that both active and passive ventricular relaxation are impaired with advancing age. Resting coronary blood flow and coronary functional hyperaemia are reduced with age, and endothelium‐dependent vasodilatation declines with age in coronary resistance arterioles. Exercise training reverses age‐induced declines in diastolic and coronary microvascular function. Thus, microvascular dysfunction and inadequate coronary perfusion are likely mechanisms of diastolic dysfunction in aged rats. Exercise training, initiated at an advanced age, reverses age‐related diastolic and microvascular dysfunction; these data suggest that late‐life exercise training can be implemented to improve coronary perfusion and diastolic function in the elderly.

Effects of age and exercise training on coronary microvascular smooth muscle phenotype and function

Coronary microvascular function and blood flow responses during acute exercise are impaired in the aged heart but can be restored by exercise training. Coronary microvascular resistance is directly dependent on vascular smooth muscle function in coronary resistance arterioles; therefore, we hypothesized that age impairs contractile function and alters the phenotype of vascular smooth muscle in coronary arterioles. We further hypothesized that exercise training restores contractile function and reverses age-induced phenotypic alterations of arteriolar smooth muscle. Young and old Fischer 344 rats underwent 10 wk of treadmill exercise training or remained sedentary. At the end of training or cage confinement, contractile responses, vascular smooth muscle proliferation, and expression of contractile proteins were assessed in isolated coronary arterioles. Both receptor- and non-receptor-mediated contractile function were impaired in coronary arterioles from aged rats. Vascular smooth muscle shifted from a differentiated, contractile phenotype to a secretory phenotype with associated proliferation of smooth muscle in the arteriolar wall. Expression of smooth muscle myosin heavy chain 1 (SM1) was decreased in arterioles from aged rats, whereas expression of phospho-histone H3 and of the synthetic protein ribosomal protein S6 (rpS6) were increased. Exercise training improved contractile responses, reduced smooth muscle proliferation and expression of rpS6, and increased expression of SM1 in arterioles from old rats. Thus age-induced contractile dysfunction of coronary arterioles and emergence of a secretory smooth muscle phenotype may contribute to impaired coronary blood flow responses, but arteriolar contractile responsiveness and a younger smooth muscle phenotype can be restored with late-life exercise training. NEW & NOTEWORTHY Aging impairs contractile function of coronary arterioles and induces a shift of the vascular smooth muscle toward a proliferative, noncontractile phenotype. Late-life exercise training reverses contractile dysfunction of coronary arterioles and restores a young phenotype to the vascular smooth muscle.

Daily muscle stretching enhances blood flow, endothelial function, capillarity, vascular volume and connectivity in aged skeletal muscle

In aged rats, daily muscle stretching increases blood flow to skeletal muscle during exercise. Daily muscle stretching enhanced endothelium‐dependent vasodilatation of skeletal muscle resistance arterioles of aged rats. Angiogenic markers and capillarity increased in response to daily stretching in muscles of aged rats. Muscle stretching performed with a splint could provide a feasible means of improving muscle blood flow and function in elderly patients who cannot perform regular aerobic exercise.