The effect of lifelong endurance exercise on cardiovascular structure and exercise function in women.

Key Points: The beneficial effects of sustained or lifelong (>25 years) endurance exercise on cardiovascular structure and exercise function have been largely established in men. The current findings indicate that committed (≥4 weekly exercise sessions) lifelong exercise results in substantial benefits in exercise capacity ( ), cardiovascular function at submaximal and maximal exercise, left ventricular mass and compliance, and blood volume compared to similarly aged or even younger (middle-age) untrained women. Endurance exercise training should be considered a key strategy to prevent cardiovascular disease with ageing in women as well as men.

Plasma matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs and aging and lifelong exercise adaptations in ventricular and arterial stiffness.

The age-associated increase in cardiac and central arterial stiffness is attenuated with lifelong (>25 years) endurance exercise in a dose-dependent manner. Remodelling of the extracellular matrix of cardiovascular structures may underpin these lifelong exercise adaptations in structural stiffness. The primary aim was to examine whether matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) levels are associated with aging and lifelong exercise-related changes in cardiac and central arterial stiffness.

Impact of Lifelong Exercise Training Dose on Ventricular-Arterial Coupling.

Background: The dynamic Starling mechanism, as assessed by beat-by-beat changes in stroke volume and left ventricular end-diastolic pressure, reflects ventricular-arterial coupling. It deteriorates with age, and is preserved in highly trained masters athletes. Currently, it remains unclear how much exercise over a lifetime is necessary to preserve efficient ventricular-arterial coupling.

The effect of lifelong exercise frequency on arterial stiffness.

Key Points: This study examined the effect of different 'doses' of lifelong (>25 years) exercise on arterial stiffening (a hallmark of vascular ageing) in older adults. There are clear dose-dependent effects of lifelong exercise training on human arterial stiffness that vary according to the site and size of the arteries. Similar to what we have observed previously with ventricular stiffening, 4-5 days week of committed exercise over a lifetime are necessary to preserve 'youthful' vascular compliance, especially of the large central arteries.

Effect of centrally acting angiotensin converting enzyme inhibitor on the exercise-induced increases in muscle sympathetic nerve activity.

Key Points: The arterial baroreflex's operating point pressure is reset upwards and rightwards from rest in direct relation to the increases in dynamic exercise intensity. The intraneural pathways and signalling mechanisms that lead to upwards and rightwards resetting of the operating point pressure, and hence the increases in central sympathetic outflow during exercise, remain to be identified. We tested the hypothesis that the central production of angiotensin II during dynamic exercise mediates the increases in sympathetic outflow and, therefore, the arterial baroreflex operating point pressure resetting during acute and prolonged dynamic exercise.

Left Ventricular Volume-Time Relation in Patients With Heart Failure With Preserved Ejection Fraction.

Elevated left ventricular (LV) filling pressures are commonly reported in patients with heart failure with preserved ejection fraction (HFpEF) and are associated with impaired relaxation in diastole. Relaxation has been assessed by Doppler, but the methods for doing so are indirect and heavily influenced by loading conditions. The aim of this study is to assess LV volume-time relation in patients with HFpEF, when correcting for left atrial driving pressure and chamber size, using cardiac magnetic resonance imaging (cMRI).

Isometric handgrip echocardiography: A noninvasive stress test to assess left ventricular diastolic function.

Background: Cycle exercise echocardiography is a useful tool to "unmask" diastolic dysfunction; however, this approach can be limited by respiratory and movement artifacts. Isometric handgrip avoids these issues while reproducibly increasing afterload and myocardial oxygen demand.

Hypothesis: Isometric handgrip echocardiography (IHE) can differentiate normal from abnormal diastolic function.

Lifelong Physical Activity Regardless of Dose Is Not Associated With Myocardial Fibrosis.

Background: Recent reports have suggested that long-term, intensive physical training may be associated with adverse cardiovascular effects, including the development of myocardial fibrosis. However, the dose-response association of different levels of lifelong physical activity on myocardial fibrosis has not been evaluated.

Methods And Results: Seniors free of major chronic illnesses were recruited from predefined populations based on the consistent documentation of stable physical activity over >25 years and were classified into 4 groups by the number of sessions/week of aerobic activities ≥30 minutes: sedentary (group 1), <2 sessions; casual (group 2), 2 to 3 sessions; committed (group 3), 4 to 5 sessions; and Masters athletes (group 4), 6 to 7 sessions plus regular competitions.

Heart Failure: Exercise-Based Cardiac Rehabilitation: Who, When, and How Intense?

The primary chronic symptom in patients with clinically stable heart failure (HF) is reduced exercise tolerance, measured as decreased peak aerobic power (peak oxygen consumption [Vo]), and is associated with reduced quality of life and survival. Exercise-based cardiac rehabilitation (EBCR) is a safe and effective intervention to improve peak Vo, muscle strength, physical functional performance, and quality of life and is associated with a reduction in overall and HF-specific hospitalization in clinically stable patients with HF. Despite these salient benefits, fewer than one-tenth of eligible patients with HF are referred for EBCR after hospitalization.

Heart rate, blood pressure and repolarization effects of an energy drink as compared to coffee.

The goal of this study was to investigate the impact of energy drinks on haemodynamic and cardiac physiology. Comparisons were made to coffee as well as water consumption. In Protocol #1 the caffeine content was normalized to body weight to represent a controlled environment.

Impact of lifelong exercise "dose" on left ventricular compliance and distensibility.

Background: Sedentary aging has deleterious effects on the cardiovascular system, including decreased left ventricular compliance and distensibility (LVCD). Conversely, Masters level athletes, who train intensively throughout adulthood, retain youthful LVCD.

Objectives: The purpose of this study was to test the hypothesis that preservation of LVCD may be possible with moderate lifelong exercise training.

The effect of lifelong exercise dose on cardiovascular function during exercise.

An increased "dose" of endurance exercise training is associated with a greater maximal oxygen uptake (Vo2max), a larger left ventricular (LV) mass, and improved heart rate and blood pressure control. However, the effect of lifelong exercise dose on metabolic and hemodynamic response during exercise has not been previously examined. We performed a cross-sectional study on 101 (69 men) seniors (60 yr and older) focusing on lifelong exercise frequency as an index of exercise dose.

Cardiovascular effects of 1 year of alagebrium and endurance exercise training in healthy older individuals.

Background: Lifelong exercise training maintains a youthful compliance of the left ventricle (LV), whereas a year of exercise training started later in life fails to reverse LV stiffening, possibly because of accumulation of irreversible advanced glycation end products. Alagebrium breaks advanced glycation end product crosslinks and improves LV stiffness in aged animals. However, it is unclear whether a strategy of exercise combined with alagebrium would improve LV stiffness in sedentary older humans.

Effects of age and aerobic fitness on myocardial lipid content.

Background: Aging and sedentary lifestyles lead to cardiac atrophy, ventricular stiffening, and impaired diastolic function. Both conditions are marked by increased adiposity, which can lead to ectopic fat deposition in nonadipocyte tissues including the myocardium. The effect of excess intramyocardial fat on cardiac function in nonobese individuals is unknown.

Cardiovascular effects of 1 year of progressive endurance exercise training in patients with heart failure with preserved ejection fraction.

Background: Heart failure with preserved ejection fraction (HFpEF) is a disease of the elderly with cardiovascular stiffening and reduced exercise capacity. Exercise training appears to improve exercise capacity and cardiovascular function in heart failure with reduced ejection fraction. However, it is unclear whether exercise training could improve cardiovascular stiffness, exercise capacity, and ventricular-arterial coupling in HFpEF.

Hemodynamic responses to rapid saline loading: the impact of age, sex, and heart failure.

Background: Hemodynamic assessment after volume challenge has been proposed as a way to identify heart failure with preserved ejection fraction. However, the normal hemodynamic response to a volume challenge and how age and sex affect this relationship remain unknown.

Methods And Results: Sixty healthy subjects underwent right heart catheterization to measure age- and sex-related normative responses of pulmonary capillary wedge pressure and mean pulmonary arterial pressure to volume loading with rapid saline infusion (100-200 mL/min).

The effect of age-related differences in body size and composition on cardiovascular determinants of VO2max.

Background: A reduction in maximal stroke volume (SVmax) and total blood volume (TBV) has been hypothesized to contribute to the decline in maximal oxygen uptake (VO2max) with healthy aging. However, these variables have rarely been collected simultaneously in a board age range to support or refute this hypothesis. It is also unclear to what extent scaling size-related cardiovascular determinants of VO2max affects the interpretation of age-related differences.

The effect of exercise training on left ventricular relaxation and diastolic suction at rest and during orthostatic stress after bed rest.

A marked reduction in upright stroke volume (SV) contributes substantially to orthostatic intolerance after exposure to spaceflight or bed rest. It is unclear whether slowed left ventricular (LV) relaxation and diastolic suction contribute to the reduction in SV or whether these changes are influenced by exercise training while in bed. Twenty-seven healthy adults completed 5 weeks of -6 deg head-down bed rest (HDBR).

Effect of healthy aging on left ventricular relaxation and diastolic suction.

Doppler ultrasound measures of left ventricular (LV) active relaxation and diastolic suction are slowed with healthy aging. It is unclear to what extent these changes are related to alterations in intrinsic LV properties and/or cardiovascular loading conditions. Seventy carefully screened individuals (38 female, 32 male) aged 21-77 were recruited into four age groups (young: <35; early middle age: 35-49; late middle age: 50-64 and seniors: ≥65 yr).

Effect of rowing ergometry and oral volume loading on cardiovascular structure and function during bed rest.

This study examined the effectiveness of a short-duration but high-intensity exercise countermeasure in combination with a novel oral volume load in preventing bed rest deconditioning and orthostatic intolerance. Bed rest reduces work capacity and orthostatic tolerance due in part to cardiac atrophy and decreased stroke volume. Twenty seven healthy subjects completed 5 wk of -6 degree head down bed rest.

Effect of ageing on left ventricular compliance and distensibility in healthy sedentary humans.

Healthy, but sedentary ageing leads to marked atrophy and stiffening of the heart, with substantially reduced cardiac compliance; but the time course of when this process occurs during normal ageing is unknown. Seventy healthy sedentary subjects (39 female; 21–77 years) were recruited from the Dallas Heart Study, a population-based, random community sample and enriched by a second random sample from employees of Texas Health Resources. Subjects were highly screened for co-morbidities and stratified into four groups according to age: G(21−34): 21–34 years, G(35−49): 35–49 years, G5(0−64): 50–64 years, G(≥65): ≥65 years.

Abnormal haemodynamic response to exercise in heart failure with preserved ejection fraction.

Aims: Peak oxygen uptake (VO(2)) is diminished in patients with heart failure with preserved ejection fraction (HFpEF) suggesting impaired cardiac reserve. To test this hypothesis, we assessed the haemodynamic response to exercise in HFpEF patients.

Methods And Results: Eleven HFpEF patients (73 ± 7 years, 7 females/4 males) and 13 healthy controls (70 ± 4 years, 6 females/7 males) were studied during submaximal and maximal exercise.

Echocardiographic indices do not reliably track changes in left-sided filling pressure in healthy subjects or patients with heart failure with preserved ejection fraction.

Background: In select patient populations, Doppler echocardiographic indices may be used to estimate left-sided filling pressures. It is not known, however, whether changes in these indices track changes in left-sided filling pressures within individual healthy subjects or patients with heart failure with preserved ejection fraction (HFpEF). This knowledge is important because it would support, or refute, the serial use of these indices to estimate changes in filling pressures associated with the titration of medical therapy in patients with heart failure.

Effects of pericardial constraint and ventricular interaction on left ventricular hemodynamics in the unloaded heart.

Pericardial constraint and ventricular interaction influence left ventricular (LV) performance when preload is high. However, it is unclear if these constraining forces modulate LV filling when the heart is unloaded, such as during upright posture, in humans. Fifty healthy individuals underwent right heart catheterization to measure pulmonary capillary wedge (PCWP) and right atrial pressure (RAP).

Patency of vein graft anastomoses facilitated with the hexalon device.

Purpose: The Hexalon system (Castlewood Surgical, Inc, Dallas, TX) is a new device that facilitates a clampless, hand-sutured, vein-to-aorta anastomoses in no-touch off-pump coronary artery bypass surgery. Hexalon-facilitated anastomoses are structurally equivalent to traditional sutured anastomoses, but can be placed during off-pump coronary artery bypass surgery. It follows that these facilitated anastomoses would show similar patency rates to traditional sutured anastomoses.