Neuroendocrine activation in heart failure is modified by endurance exercise training

Associated lifestyle factors of elevated plasma aldosterone concentration in community population, gender-stratified analysis of a cross-sectional survey

BACKGROUND

Aldosterone plays important parts in development of cardio-metabolic diseases as end product of renin-angiotensin-aldosterone system. However, factors elevating circulating aldosterone are not clear, and lifestyle-related factors are suggested to be involved, whereas less studied. Therefore, we aimed to explore the association of lifestyle factors with plasma aldosterone concentration (PAC) in community population.

METHODS

In this cross-sectional study, we recruited participants using multistage random sampling from Emin China in 2019, and collected data and fasting blood samples. The considered lifestyle factors included obesity parameters (neck circumference, abdominal circumference), alcohol consumption, blood pressure (BP), physical activity, sleep duration, sleep quality, mental state (depression and anxiety), fasting blood glucose (FBG), and lipid profiles (total cholesterol and triglyceride). PAC was measured using radioimmunoassay. We performed sex-stratified linear and logistic regressions to explore associated factors of PAC. Component analysis was further performed to identify the main factors affecting PAC.

RESULTS

Twenty-seven thousand four hundred thirty-six participants with 47.1% men were included. Obesity parameters (neck circumference, abdominal circumference), glucose metabolism (FBG), psychological status (anxiety status in men and women, depression status in men), BP, liver function (in men), lipid metabolism (TC and TG in men), sleep parameters (sleep quality in women), and renal function (in women) are the main factors associated with elevated PAC.

CONCLUSION

lower physical activity, alcohol consumption, higher BP, fat accumulation, dyslipidemia, higher fasting blood glucose, and presence of depression and anxiety were the main factors associated with eleveated PAC.

Effect of exercise training on the renin-angiotensin-aldosterone system: a meta-analysis

Blood pressure (BP) management reduces the risk of cardiovascular disease (CVD). The renin-angiotensin-aldosterone system (RAAS) plays an important role in regulating and maintaining blood volume and pressure. This analysis aimed to investigate the effect of exercise training on plasma renin, angiotensin-II and aldosterone, epinephrine, norepinephrine, urinary sodium and potassium, BP and heart rate (HR). We systematically searched PubMed, Web of Science, and the Cochrane Library of Controlled Trials until 30 November 2022. The search strategy included RAAS key words in combination with exercise training terms and medical subject headings. Manual searching of reference lists from systematic reviews and eligible studies completed the search. A random effects meta-analysis model was used. Eighteen trials with a total of 803 participants were included. After exercise training, plasma angiotensin-II (SMD -0.71; 95% CI -1.24, -0.19; p = 0.008; n = 9 trials), aldosterone (SMD -0.37; 95% CI -0.65, -0.09; p = 0.009; n = 8 trials) and norepinephrine (SMD -0.82; 95% CI -1.18, -0.46; p < 0.001; n = 8 trials) were reduced. However, plasma renin activity, epinephrine, and 24-h urinary sodium and potassium excretion remained unchanged with exercise training. Systolic BP was reduced (MD -6.2 mmHg; 95% CI -9.9, -2.6; p = 0.001) as was diastolic BP (MD -4.5 mmHg; 95% CI -6.9, -2.1; p < 0.001) but not HR (MD -3.0 bpm; 95% CI -6.0, 0.4; p = 0.053). Exercise training may reduce some aspects of RAAS and sympathetic nervous system activity, and this explains some of the anti-hypertensive response.

Cardiovascular Benefits of Resistance Training in Patients With Heart Failure With Reduced Ejection Fraction: A Systematic Review

Cardiovascular diseases pose a serious problem for health globally. Among these, congestive heart failure is the leading cause of mortality and morbidity worldwide. According to the recent census, heart failure contributes to a huge financial burden annually. Exercise therapy is an integral part of the non-pharmacological management of heart failure. Due to the availability of various types of exercise therapies and rapid advancements in the existing evidence, it is often challenging to prescribe an appropriate exercise program. Although there is unequivocal evidence supporting the cardiovascular benefits of aerobic therapy, the incorporation of resistance training into exercise regimens should also be encouraged due to its effects on muscular endurance and ameliorating skeletal myopathy in heart failure. In this study, we used a systematic literature review (SLR) approach to give an overview of the current literature and highlight the cardiovascular benefits of resistance training, alone or in combination with aerobic training. We reviewed articles from well-recognized journals published between 2013 and 2023, finally narrowing down to nine selected papers for a thorough analysis. The inclusion criteria comprise studies dealing with heart failure with reduced ejection fraction (HFrEF), resistance training alone or in combination with aerobic therapy, and studies available for free in either the PubMed or Google Scholar databases. The systematic review revealed that resistance training in combination with aerobic therapy has greater cardiovascular benefits than either resistance or aerobic therapy alone. A few unique approaches, like periodic intermittent muscular exercise (PRIME) and super circuit training (SCT), have demonstrated an improvement in cardiac and non-cardiac clinical outcomes compared to conventional exercise therapies. Moreover, various factors, like lack of motivation and lack of time, contribute to poor adherence to exercise therapy. Approaches like telerehabilitation and designing exercise regimens with activities that patients enjoy have led to improvements in long-term adherence rates. Nevertheless, further exploration and research by conducting randomized controlled trials on a larger scale is essential to explore the potential of resistance training in the rehabilitation of patients with heart failure with reduced ejection fraction and to develop the most effective exercise therapy.

The Role of Aldosterone and Ideal Cardiovascular Health in Incident Cardiovascular Disease: The Jackson Heart Study

Background

Higher levels of ideal cardiovascular health (ICH) are associated with lower levels of aldosterone and incidence of cardiovascular disease (CVD). However, the degree to which aldosterone mediates the association between ICH and CVD incidence has not been explored. Thus, we investigated the mediational role of aldosterone in the association of 5 components of ICH (cholesterol, body mass index (BMI), physical activity, diet and smoking) with incident CVD and the mediational role of blood pressure (BP) and glucose in the association of aldosterone with incident CVD in a cohort of African Americans (AA).

Methods

The Jackson Heart Study is a prospective cohort of AAs adults with data on CVD outcomes. Aldosterone, ICH metrics and baseline characteristics were collected at exam 1 (2000-2004). ICH score was developed by summing 5 ICH metrics (smoking, dietary intake, physical activity, BMI, and total cholesterol) and grouped into two categories (0-2 and ≥3 metrics). Incident CVD was defined as stroke, coronary heart disease, or heart failure. Cox proportional hazard regression models were used to model the association of categorical ICH score with incident CVD. The R Package Mediation was utilized to examine: 1) The mediational role of aldosterone in the association of ICH with incident CVD and 2) The mediational role of blood pressure and glucose in the association of aldosterone with incident CVD.

Results

Among 3,274 individuals (mean age: 54±12.4 years, 65% female), there were 368 cases of incident CVD over a median of 12.7 years. The risk of incident CVD was 46% lower (HR: 0.54; 95%CI 0.36, 0.80) in those with ≥3 ICH metrics at baseline compared to 0-2. Aldosterone mediated 5.4% (p = 0.006) of the effect of ICH on incident CVD. A 1-unit increase in log-aldosterone was associated with a 38% higher risk of incident CVD (HR 1.38, 95%CI: 1.19, 1.61) with BP and glucose mediating 25.6% (p<0.001) and 4.8% (p = 0.048), respectively.

Conclusion

Aldosterone partially mediates the association of ICH with incident CVD and both blood pressure and glucose partially mediate the association of aldosterone with incident CVD, emphasizing the potential importance of aldosterone and ICH in risk of CVD among AAs.

Association between Right Ventricular Function and Exercise Capacity in Patients with Chronic Heart Failure

Background: The association between right ventricular function and exercise capacity in patients with chronic heart failure remains uncertain. Several studies very recently mentioned the association between right ventricular reserve and exercise capacity, whereas the implication of tricuspid annular plane systolic excursion (TAPSE) remains uninvestigated. We aimed to assess the impact of TAPSE on exercise capacity in cardiac rehabilitation candidates. Methods: Data from patients with chronic heart failure who received cardiopulmonary exercise tests and transthoracic echocardiography prior to cardiac rehabilitation were retrospectively collected, and their association was investigated. Results: A total of 169 patients with chronic heart failure (70.3 ± 11.7 years old, 74.6% men) were included. Tertiled tricuspid annular plane systolic excursion significantly stratified anaerobic threshold (10.2 ± 2.2, 11.4 ± 2.2, and 12.2 ± 2.8 mm; p < 0.01) and peak oxygen consumption (15.9 ± 4.5, 18.3 ± 5.3, and 19.8 ± 5.6 mm; p < 0.01). In the multivariate logistic regression analyses, TAPSE was an independent factor associated with anaerobic threshold and peak oxygen consumption (p < 0.05 for both). Conclusions: Right ventricular impairment was associated with reduced exercise capacity in patients with chronic heart failure. Such knowledge would be useful to estimate patients’ exercise capacity and prescribe cardiac rehabilitation. Its longitudinal association and clinical implication need further studies.

The Role of Exercise-Induced Molecular Processes and Vitamin D in Improving Cardiorespiratory Fitness and Cardiac Rehabilitation in Patients With Heart Failure

Heart failure (HF) still affects millions of people worldwide despite great advances in therapeutic approaches in the cardiovascular field. Remarkably, unlike pathological hypertrophy, exercise leads to beneficial cardiac hypertrophy characterized by normal or enhanced contractile function. Exercise-based cardiac rehabilitation improves cardiorespiratory fitness and, as a consequence, ameliorates the quality of life of patients with HF. Particularly, multiple studies demonstrated the improvement in left ventricular ejection fraction (LVEF) among patients with HF due to the various processes in the myocardium triggered by exercise. Exercise stimulates IGF-1/PI3K/Akt pathway activation involved in muscle growth in both the myocardium and skeletal muscle by regulating protein synthesis and catabolism. Also, physical activity stimulates the activation of the mitogen-activated protein kinase (MAPK) pathway which regulates cellular proliferation, differentiation and apoptosis. In addition, emerging data pointed out the anti-inflammatory effects of exercises as well. Therefore, it is of utmost importance for clinicians to accurately evaluate the patient’s condition by performing a cardiopulmonary exercise test and/or a 6-min walking test. Portable devices with the possibility to measure exercise capacity proved to be very useful in this setting as well. The aim of this review is to gather together the molecular processes triggered by the exercise and available therapies in HF settings that could ameliorate heart performance, with a special focus on strategies such as exercise-based cardiac rehabilitation.

Sex-Specific Impacts of Exercise on Cardiovascular Remodeling

Cardiovascular diseases (CVD) remain the leading cause of death in men and women. Biological sex plays a major role in cardiovascular physiology and pathological cardiovascular remodeling. Traditionally, pathological remodeling of cardiovascular system refers to the molecular, cellular, and morphological changes that result from insults, such as myocardial infarction or hypertension. Regular exercise training is known to induce physiological cardiovascular remodeling and beneficial functional adaptation of the cardiovascular apparatus. However, impact of exercise-induced cardiovascular remodeling and functional adaptation varies between males and females. This review aims to compare and contrast sex-specific manifestations of exercise-induced cardiovascular remodeling and functional adaptation. Specifically, we review (1) sex disparities in cardiovascular function, (2) influence of biological sex on exercise-induced cardiovascular remodeling and functional adaptation, and (3) sex-specific impacts of various types, intensities, and durations of exercise training on cardiovascular apparatus. The review highlights both animal and human studies in order to give an all-encompassing view of the exercise-induced sex differences in cardiovascular system and addresses the gaps in knowledge in the field.

The Future of Exercise-Based Cardiac Rehabilitation for Patients With Heart Failure

Cardiac rehabilitation (CR) is a comprehensive program that includes exercise training, titration of medical therapy, lifestyle modification, educational support, and psychosocial assessment. All these components are safe and beneficial resulting in significant improvements in quality of life, functional capacity, mortality, and hospital readmission. Current guidelines support its use in a broad spectrum of cardiac disease. This review focuses on exercise-based CR for heart failure (HF) patients in whom CR is a recommended treatment. Exercise should be prescribed according to a personalized approach, optimizing, and tailoring the rehabilitative program to the patient's characteristics. Specific CR programs are dedicated to older patients, those with HF and preserved ejection fraction, and recipients of cardiac implantable electronic devices or left ventricular assistance device. Telemedicine may increase CR participation and overcome some of the barriers that limit its utilization.

Exercise-Based Cardiac Rehabilitation Programs in Heart Failure Patients

Exercise training is recommended for patients with heart failure by major societies' guidelines. It improves exercise capacity and quality of life, reduces symptoms of depression, can improve survival, and reduce the risk for hospitalizations. Exercise-based cardiac rehabilitation can be offered with different modalities, such as continuous or interval aerobic training, resistance, and inspiratory muscle training. The intervention must follow an accurate evaluation of the patient's cardiovascular conditions and functional capacity. Despite the multiple benefits of exercise training, there is a lack of adherence to exercise-based programs, due to socioeconomic factors, patients' characteristics, and lack of referral.

Physical activity for patients with heart failure: Position paper from the heart failure (GICC) and cardiac rehabilitation (GERS-P) Working Groups of the French Society of Cardiology

Physical activity is important in heart failure to improve functional capacity, quality of life and prognosis, and is a class IA recommendation in the European Society of Cardiology guidelines (Ponikowski et al., 2016). The benefits of exercise training are widely recognized. Cardiac rehabilitation centres offer tailored exercise training to patients with heart failure, as part of specialized multidisciplinary care, alongside pharmacological treatment optimization and patient education. After cardiac rehabilitation, maintenance of regular physical activity long term is essential, as the benefits of exercise training vanish within a few weeks. Unfortunately, only 10% of patients benefit from a cardiac rehabilitation programme after hospitalization for acute heart failure, and the majority of patients do not pursue long-term physical activity. In this paper, two Working Groups of the French Society of Cardiology (the heart failure group [Groupe Insuffisance Cardiaque et Cardiomyopathies; GICC] and the cardiac rehabilitation group [Groupe Exercice Réadaptation Sport et Prévention; GERS-P]) discuss the obstacles to broader access to cardiac rehabilitation centres, and propose ways to improve the diffusion of cardiac rehabilitation programmes and encourage long-term adherence to physical activity.

The Association of Life's Simple 7 with Aldosterone among African Americans in the Jackson Heart Study

Background: Among African Americans (AAs), attaining higher levels of American Heart Association (AHA) ideal cardiovascular health (Life’s Simple 7 [LS7]) is associated with lower risk of diabetes and cardiovascular disease (CVD). We previously showed that aldosterone is associated with higher risk of diabetes and CVD in AAs. Thus, we investigated the association of LS7 metrics with aldosterone in the Jackson Heart Study (JHS). Methods: Ideal metrics were defined by AHA 2020 goals for health behaviors (smoking, dietary intake, physical activity, and body mass index) and health factors (total cholesterol, blood pressure, and fasting glucose). The number of ideal LS7 metrics attained at baseline were summed into a continuous score (0–7) and categorical groups (Poor: 0–1, Intermediate: 2–3, and Ideal: ≥4 ideal LS7 metrics). Multivariable linear regression was used. Results: Among 4,095 JHS participants (mean age 55 ± 13 years, 65% female), median serum aldosterone was 4.90, 4.30, and 3.70 ng/dL in the poor (n = 1132), intermediate (n = 2288) and ideal (n = 675) categories respectively. Aldosterone was 15% [0.85 (0.80, 0.90)] and 33% [0.67 (0.61, 0.75)] lower in the intermediate and ideal LS7 categories compared to the poor LS7 category. Each additional LS7 metric attained on continuous LS7 score (0–7) was associated with an 11% [0.89 (0.86, 0.91)] lower aldosterone level with variation by sex with women having a 15% lower aldosterone vs. 5% in men. Conclusions: Higher attainment of ideal LS7 metrics was associated with lower serum aldosterone among AAs with a greater magnitude of association among women compared to men.

Effects of aerobic exercise training on ACE and ADRB2 gene expression, plasma angiotensin II level, and flow-mediated dilation: a study on obese postmenopausal women with prehypertension

OBJECTIVE

The purpose of this study is to determine the effect of 10 weeks of moderate-intensity aerobic exercise training (MIET) on blood pressure (BP), angiotensin-converting enzyme (ACE) and β2-adrenergic receptor (ADRB2) gene expression in leukocytes, plasma angiotensin II (Ang II), and flow-mediated dilation (FMD) in obese postmenopausal women (PMW) with prehypertension.

METHODS

Twenty-four obese prehypertensive PMW (aged 50-70 y; body mass index ≥30 kg/m) randomly assigned to control (n = 12) and exercise (n = 12) groups. Exercise group performed MIET (25-40 min/d, 3 d/wk at 50%-70% of heart rate reserve) for 10 weeks. Control group maintained their normal daily physical activity level. Body composition, VO2max, BP, ACE and ADRB2 gene expression, plasma Ang II, and FMD were measured before and after the training program.

RESULTS

After MIET, systolic and diastolic BPs decreased by 4.6% and 2.4%, respectively (P < 0.001). Plasma Ang II level decreased by 45.7%, whereas FMD increased by 86% in the exercise group (P < 0.001). Exercise training resulted in a threefold increase in ADRB2 and a fourfold decrease in ACE gene expressions (P < 0.05). Training-induced changes in BP inversely associated with the changes in FMD and ADRB2 (r values range -0.55 to -0.78), and positively associated with Ang II and ACE (r values range 0.68-0.86) (P < 0.001).

CONCLUSIONS

Ten weeks of MIET modulates ACE and ADRB2 gene expression, decreases Ang II plasma levels, and improves endothelial function in obese PMW, and these alterations are associated with reduction in BP.

Exercise Therapy for Older Heart Failure Patients

Both the aging process and heart failure (HF) syndrome are characterized by a dramatic reduction of aerobic capacity. Significant decreases in muscle mass and strength are also common. Few HF training studies have included meaningful numbers of older individuals, especially those greater than 80 years of age and older women with HF with reduced ejection fraction. The modest data available suggest similar benefits in older patients and excellent safety. Resistance training may provide additional benefit. Whether exercise training can reduce mortality, hospitalizations, and overall health care costs in older adults with HF awaits the outcome of adequately powered multicenter trials.

Exercise-Based Rehabilitation for Heart Failure: Clinical Evidence

People with heart failure experience marked reduction in their exercise capacity which has detrimental effects on their activities of daily living, health-related quality of life, and ultimately their hospital ad-mission rate and mortality. Numerous cardiac rehabilitation studies have demonstrated functional benefits, improvement in quality of life and clinical outcomes from exercise training in patients with HFrEF. Based on evidences, the American College of Cardiology/American Heart Association, European Society of Cardiology, and National Institute for Health and Care Excellence(NICE) consistently recommend exercise-based cardiac rehabilitation(CR) as an effective and safe adjunct for patients with stable class II to III heart failure (HF) who do not have advanced arrhythmias and who do not have other limitations to exercise. This recommendation applies to patients with HFrEF as well as to patients with HFpEF besides patients with class IV HF, although the data are not as robust for patients with HFpEF. In this article, the clinical evidence on effects of exercise for HFrEF and HFpEF as well as end-stage heart failure were separately reviewed.

Experimental Evidences Supporting the Benefits of Exercise Training in Heart Failure

Heart Failure (HF), a common end point for many cardiovascular diseases, is a syndrome with a very poor prognosis. Although clinical trials in HF have achieved important outcomes in reducing mortality, little is known about functional mechanisms conditioning health improvement in HF patients. In parallel with clinical studies, basic science has been providing important discoveries to understand the mechanisms underlying the pathophysiology of HF, as well as to identify potential targets for the treatment of this syndrome. In spite of being the end-point of cardiovascular derangements caused by different etiologies, autonomic dysfunction, sympathetic hyperactivity, oxidative stress, inflammation and hormonal activation are common factors involved in the progression of this syndrome. Together these causal factors create a closed link between three important organs: brain, heart and the skeletal muscle. In the past few years, we and other groups have studied the beneficial effects of aerobic exercise training as a safe therapy to avoid the progression of HF. As summarized in this chapter, exercise training, a non-pharmacological tool without side effects, corrects most of the HF-induced neurohormonal and local dysfunctions within the brain, heart and skeletal muscles. These adaptive responses reverse oxidative stress, reduce inflammation, ameliorate neurohormonal control and improve both cardiovascular and skeletal muscle function, thus increasing the quality of life and reducing patients' morbimortality.

The effect of endurance training on exercise capacity following cardiac resynchronization therapy in chronic heart failure patients: a pilot trial

BACKGROUND

Both endurance training (ET) and cardiac resynchronization therapy (CRT) improve quality of life (QOL) and exercise tolerance in patients with advanced chronic heart failure (CHF).

DESIGN

A randomized intervention trial to study the effect on exercise capacity of ET in addition to CRT in patients with CHF and dyssynchrony.

METHODS

Seventeen patients (eight men, aged 59+/-9 years) with CHF and dyssynchrony were randomized to CRT with (n=8) or without (n=9) ET and compared with two matched control CHF groups (standard care with ET: n=9, standard care only: n=10). At baseline and after 5 months, exercise tolerance, left ventricular (LV) remodelling, QOL and NT-pro brain natriuretic peptide (NT-proBNP) levels were assessed.

RESULTS

Peak oxygen consumption (VO2peak), maximal workload (Wattmax), circulatory power, LV ejection fraction, dyssynchrony and QOL improved in both CRT groups. However, the increase in VO2peak (+40% versus +16%, P=0.005), Wattmax (+43% versus +13%, P=0.0005), and circulatory power (+74% versus +32%, P=0.01), was significantly greater in the trained versus the untrained CRT patients. Comparison of the four patient groups confirmed the cumulative effects of CRT plus ET.

CONCLUSIONS

ET in resynchronized CHF patients is feasible and further enhances exercise tolerance. Patients with severe CHF should be prescribed an exercise training programme after implantation in order to maximize the expected benefit.

Changes in Hepatic Venous Pressure Gradient Induced by Physical Exercise in Cirrhosis: Results of a Pilot Randomized Open Clinical Trial

OBJECTIVES

Exercise has been scarcely studied in patients with cirrhosis, and prior evidence showed hepatic venous pressure gradient (HVPG) to be increased in response to exercise. The aim of this study was to investigate the effects of a supervised physical exercise program (PEP) in patients with cirrhosis.

METHODS

In an open-label, pilot clinical trial, patients with cirrhosis were randomized to PEP (cycloergometry/kinesiotherapy plus nutritional therapy, n=14) or control (nutritional therapy, n=15); for 14 weeks. Primary outcomes were: the effect of PEP in HVPG, and quality of life (chronic liver disease questionnaire, CLDQ). As secondary outcomes we investigated changes in physical fitness (cardiopulmonary exercise testing), nutritional status (phase angle-bioelectrical impedance), ammonia levels, and safety.

RESULTS

Twenty-two patients completed the study (11 each). HVPG decreased in subjects allocated to PEP (-2.5 mm Hg (interquartile range: -5.25 to 2); P=0.05), and increased in controls (4 mm Hg (0-5); P=0.039), with a significant between-groups difference (P=0.009). No major changes were noted in CLDQ in both groups. There was significant improvement in ventilatory efficiency (VE/VCO2) in PEP group (-1.9 (-3.12 to -0.1); P=0.033), but not in controls (-0.4 (-5.7 to 1.4); P=0.467). Phase angle improvement and a less-pronounced exercise-induced hyperammonemia were noted only in PEP group. No episodes of variceal bleeding or hepatic encephalopathy were observed.

CONCLUSIONS

A supervised PEP in patients with cirrhosis decreases the HVPG and improves nutritional status with no changes in quality of life. Further studies evaluating physical training in cirrhosis are eagerly awaited in order to better define the benefits of sustained exercise. ClinicalTrials.gov:NCT00517738.

Exercise training normalizes renal blood flow responses to acute hypoxia in experimental heart failure: role of the α1-adrenergic receptor

Recent data suggest that exercise training (ExT) is beneficial in chronic heart failure (CHF) because it improves autonomic and peripheral vascular function. In this study, we hypothesized that ExT in the CHF state ameliorates the renal vasoconstrictor responses to hypoxia and that this beneficial effect is mediated by changes in α1-adrenergic receptor activation. CHF was induced in rabbits. Renal blood flow (RBF) and renal vascular conductance (RVC) responses to 6 min of 5% isocapnic hypoxia were assessed in the conscious state in sedentary (SED) and ExT rabbits with CHF with and without α1-adrenergic blockade. α1-adrenergic receptor expression in the kidney cortex was also evaluated. A significant decline in baseline RBF and RVC and an exaggerated renal vasoconstriction during acute hypoxia occurred in CHF-SED rabbits compared with the prepaced state (P < 0.05). ExT diminished the decline in baseline RBF and RVC and restored changes during hypoxia to those of the prepaced state. α1-adrenergic blockade partially prevented the decline in RBF and RVC in CHF-SED rabbits and eliminated the differences in hypoxia responses between SED and ExT animals. Unilateral renal denervation (DnX) blocked the hypoxia-induced renal vasoconstriction in CHF-SED rabbits. α1-adrenergic protein in the renal cortex of animals with CHF was increased in SED animals and normalized after ExT. These data provide evidence that the acute decline in RBF during hypoxia is caused entirely by the renal nerves but is only partially mediated by α1-adrenergic receptors. Nonetheless, α1-adrenergic receptors play an important role in the beneficial effects of ExT in the kidney.

Differential Role of G Protein-Coupled Receptor Kinase 5 in Physiological Versus Pathological Cardiac Hypertrophy

RATIONALE

G protein-coupled receptor kinases (GRKs) are dynamic regulators of cellular signaling. GRK5 is highly expressed within myocardium and is upregulated in heart failure. Although GRK5 is a critical regulator of cardiac G protein-coupled receptor signaling, recent data has uncovered noncanonical activity of GRK5 within nuclei that plays a key role in pathological hypertrophy. Targeted cardiac elevation of GRK5 in mice leads to exaggerated hypertrophy and early heart failure after transverse aortic constriction (TAC) because of GRK5 nuclear accumulation.

OBJECTIVE

In this study, we investigated the role of GRK5 in physiological, swimming-induced hypertrophy (SIH).

METHODS AND RESULTS

Cardiac-specific GRK5 transgenic mice and nontransgenic littermate control mice were subjected to a 21-day high-intensity swim protocol (or no swim sham controls). SIH and specific molecular and genetic indices of physiological hypertrophy were assessed, including nuclear localization of GRK5, and compared with TAC. Unlike after TAC, swim-trained transgenic GRK5 and nontransgenic littermate control mice exhibited similar increases in cardiac growth. Mechanistically, SIH did not lead to GRK5 nuclear accumulation, which was confirmed in vitro as insulin-like growth factor-1, a known mediator of physiological hypertrophy, was unable to induce GRK5 nuclear translocation in myocytes. We found specific patterns of altered gene expression between TAC and SIH with GRK5 overexpression. Further, SIH in post-TAC transgenic GRK5 mice was able to preserve cardiac function.

CONCLUSIONS

These data suggest that although nuclear-localized GRK5 is a pathological mediator after stress, this noncanonical nuclear activity of GRK5 is not induced during physiological hypertrophy.

Effect of exercise training on the renin-angiotensin-aldosterone system in healthy individuals: a systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to evaluate the effect of exercise training on parameters of the renin-angiotensin-aldosterone system (RAAS) in healthy adults, and to investigate the relation with training induced changes in blood pressure. A systematic search was conducted and we included randomized controlled trials lasting ⩾4 weeks investigating the effects of exercise on parameters of the RAAS in healthy adults (age ⩾18 years) and published in a peer-reviewed journal up to December 2013. Fixed effects models were used and data are reported as weighted means and 95% confidence limits (CL). Eleven randomized controlled trials with a total of 375 individuals were included. Plasma renin activity was reduced after exercise training (n= 7 trials, standardized mean difference -0.25 (95% CL -0.5 to -0.001), P=0.049), whereas no effect was observed on serum aldosterone ((n= 3 trials; standardized mean difference -0.79 (-1.97 to +0.39)) or angiotensin II (n=3 trials; standardized mean difference -0.16 (-0.61 to +0.30). Significant reductions in systolic blood pressure -5.65 mm Hg (-8.12 to -3.17) and diastolic blood pressure -3.64 mm Hg (-5.4 to -1.91) following exercise training were observed. No relation was found between net changes in plasma renin activity and net changes in blood pressure (P>0.05). To conclude, although we observed a significant reduction in plasma renin activity following exercise training this was not related to the observed blood pressure reduction. Given the small number of studies and small sample sizes, larger well-controlled randomized studies are required to confirm our results and to investigate the potential role of the RAAS in the observed improvements in blood pressure following exercise training.

Exercise training in chronic heart failure: improving skeletal muscle O2 transport and utilization

Chronic heart failure (CHF) impairs critical structural and functional components of the O2 transport pathway resulting in exercise intolerance and, consequently, reduced quality of life. In contrast, exercise training is capable of combating many of the CHF-induced impairments and enhancing the matching between skeletal muscle O2 delivery and utilization (Q̇mO2 and V̇mO2 , respectively). The Q̇mO2 /V̇mO2 ratio determines the microvascular O2 partial pressure (PmvO2 ), which represents the ultimate force driving blood-myocyte O2 flux (see Fig. 1). Improvements in perfusive and diffusive O2 conductances are essential to support faster rates of oxidative phosphorylation (reflected as faster V̇mO2 kinetics during transitions in metabolic demand) and reduce the reliance on anaerobic glycolysis and utilization of finite energy sources (thus lowering the magnitude of the O2 deficit) in trained CHF muscle. These adaptations contribute to attenuated muscle metabolic perturbations (e.g., changes in [PCr], [Cr], [ADP], and pH) and improved physical capacity (i.e., elevated critical power and maximal V̇mO2 ). Preservation of such plasticity in response to exercise training is crucial considering the dominant role of skeletal muscle dysfunction in the pathophysiology and increased morbidity/mortality of the CHF patient. This brief review focuses on the mechanistic bases for improved Q̇mO2 /V̇mO2 matching (and enhanced PmvO2 ) with exercise training in CHF with both preserved and reduced ejection fraction (HFpEF and HFrEF, respectively). Specifically, O2 convection within the skeletal muscle microcirculation, O2 diffusion from the red blood cell to the mitochondria, and muscle metabolic control are particularly susceptive to exercise training adaptations in CHF. Alternatives to traditional whole body endurance exercise training programs such as small muscle mass and inspiratory muscle training, pharmacological treatment (e.g., sildenafil and pentoxifylline), and dietary nitrate supplementation are also presented in light of their therapeutic potential. Adaptations within the skeletal muscle O2 transport and utilization system underlie improvements in physical capacity and quality of life in CHF and thus take center stage in the therapeutic management of these patients.

Exercise training attenuates chemoreflex-mediated reductions of renal blood flow in heart failure

In chronic heart failure (CHF), carotid body chemoreceptor (CBC) activity is increased and contributes to increased tonic and hypoxia-evoked elevation in renal sympathetic nerve activity (RSNA). Elevated RSNA and reduced renal perfusion may contribute to development of the cardio-renal syndrome in CHF. Exercise training (EXT) has been shown to abrogate CBC-mediated increases in RSNA in experimental heart failure; however, the effect of EXT on CBC control of renal blood flow (RBF) is undetermined. We hypothesized that CBCs contribute to tonic reductions in RBF in CHF, that stimulation of the CBC with hypoxia would result in exaggerated reductions in RBF, and that these responses would be attenuated with EXT. RBF was measured in CHF-sedentary (SED), CHF-EXT, CHF-carotid body denervation (CBD), and CHF-renal denervation (RDNX) groups. We measured RBF at rest and in response to hypoxia (FiO2 10%). All animals exhibited similar reductions in ejection fraction and fractional shortening as well as increases in ventricular systolic and diastolic volumes. Resting RBF was lower in CHF-SED (29 ± 2 ml/min) than in CHF-EXT animals (46 ± 2 ml/min, P < 0.05) or in CHF-CBD animals (42 ± 6 ml/min, P < 0.05). In CHF-SED, RBF decreased during hypoxia, and this was prevented in CHF-EXT animals. Both CBD and RDNX abolished the RBF response to hypoxia in CHF. Mean arterial pressure increased in response to hypoxia in CHF-SED, but was prevented by EXT, CBD, and RDNX. EXT is effective in attenuating chemoreflex-mediated tonic and hypoxia-evoked reductions in RBF in CHF.

How should we advise heart failure patients on exercise and what should we tell them?

The article discusses the problem of motivating and encouraging patients with heart failure to perform regular exercise training. Firstly, the benefits of exercise training are presented, and rational and convincing arguments justifying its implementation in heart failure patients are provided. Secondly, the issue of overcoming barriers to exercise training implementation is considered. Finally, the role of the medical team and family members in supporting patients with heart failure in long-term adherence to recommendations is defined and analyzed. In addition, the article presents various ways of performing exercise training easily.

Regular exercise improves weight stability in patients with advanced heart failure

OBJECTIVES

The purpose of this study was to determine if a progressive, prescribed home-based aerobic exercise program would alter the natural physiological processes that maintain fluid balance stability in patients with New York Heart Association (NYHA) class III/IV heart failure after medical optimization (titration of oral medical therapy with or without the infusion of an intravenous inotrope).

METHODS

A total of 56 men and women from a large tertiary trauma I hospital were enrolled with 56 subjects contributing to baseline analysis and 42 subjects at 24 weeks. Subjects were diagnosed with heart failure via NYHA classification IV or III for at least 6 months and were hospitalized for a current acute decompensation exacerbation in which they were being medically optimized. The exercise intervention was a home-based, prescribed, progressive aerobic exercise program lasting for 24 weeks. The exercise participants had weekly phone calls to gather data and progress the exercise program and one 12-week follow up. The usual care participants received random phone calls to collect data and had one 12-week follow up visit to attain physical assessment values.

RESULTS

Subjects were primarily female (59%), nonwhite (54%), and NYHA class IV (52%) versus class III (48%). The mean age was 58 years (±11.8 years). The subjects had a mean ejection fraction of 17.7 % (±7%) and mean maximal oxygen consumption of 12.1 (±3.4). Using a hierarchical multiple regression model, it was demonstrated that an exercise prescription (intensity, frequency, duration) significantly predicted 24 h weight fluctuations within a NYHA class III/IV heart failure population after medical optimization (R(2) linear = 0.713, F = 3.224, p = 0.015).

CONCLUSION

This study demonstrated that exercise is a successful adjunctive therapy to managing the daily weight variability or fluid status instability of patients with NYHA class III/IV heart failure that is often a debilitating aspect of the syndrome.

Cardiac remodeling and physical training post myocardial infarction

After myocardial infarction (MI), the heart undergoes extensive myocardial remodeling through the accumulation of fibrous tissue in both the infarcted and noninfarcted myocardium, which distorts tissue structure, increases tissue stiffness, and accounts for ventricular dysfunction. There is growing clinical consensus that exercise training may beneficially alter the course of post-MI myocardial remodeling and improve cardiac function. This review summarizes the present state of knowledge regarding the effect of post-MI exercise training on infarcted hearts. Due to the degree of difficulty to study a viable human heart at both protein and molecular levels, most of the detailed studies have been performed by using animal models. Although there are some negative reports indicating that post-MI exercise may further cause deterioration of the wounded hearts, a growing body of research from both human and animal experiments demonstrates that post-MI exercise may beneficially alter the course of wound healing and improve cardiac function. Furthermore, the improved function is likely due to exercise training-induced mitigation of renin-angiotensin-aldosterone system, improved balance between matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-1, favorable myosin heavy chain isoform switch, diminished oxidative stress, enhanced antioxidant capacity, improved mitochondrial calcium handling, and boosted myocardial angiogenesis. Additionally, meta-analyses revealed that exercise-based cardiac rehabilitation has proven to be effective, and remains one of the least expensive therapies for both the prevention and treatment of cardiovascular disease, and prevents re-infarction.

Effects of exercise training on neurovascular control and skeletal myopathy in systolic heart failure

Neurohormonal excitation and dyspnea are the hallmarks of heart failure (HF) and have long been associated with poor prognosis in HF patients. Sympathetic nerve activity (SNA) and ventilatory equivalent of carbon dioxide (VE/VO2) are elevated in moderate HF patients and increased even further in severe HF patients. The increase in SNA in HF patients is present regardless of age, sex, and etiology of systolic dysfunction. Neurohormonal activation is the major mediator of the peripheral vasoconstriction characteristic of HF patients. In addition, reduction in peripheral blood flow increases muscle inflammation, oxidative stress, and protein degradation, which is the essence of the skeletal myopathy and exercise intolerance in HF. Here we discuss the beneficial effects of exercise training on resting SNA in patients with systolic HF and its central and peripheral mechanisms of control. Furthermore, we discuss the exercise-mediated improvement in peripheral vasoconstriction in patients with HF. We will also focus on the effects of exercise training on ventilatory responses. Finally, we review the effects of exercise training on features of the skeletal myopathy in HF. In summary, exercise training plays an important role in HF, working synergistically with pharmacological therapies to ameliorate these abnormalities in clinical practice.

Effect of yoga regimen on lung functions including diffusion capacity in coronary artery disease patients: A randomized controlled study

BACKGROUND

Lung functions are found to be impaired in coronary artery disease (CAD), congestive heart failure, left ventricular dysfunction, and after cardiac surgery. Diffusion capacity progressively worsens as the severity of CAD increases due to reduction in lung tissue participating in gas exchange.

AIMS AND OBJECTIVES

Pranayama breathing exercises and yogic postures may play an impressive role in improving cardio-respiratory efficiency and facilitating gas diffusion at the alveolo-capillary membrane. This study was done to see the effect of yoga regimen on lung functions particularly diffusion capacity in CAD patients.

MATERIALS AND METHODS

A total of 80 stable CAD patients below 65 years of age of both sexes were selected and randomized into two groups of 40 each. Group I CAD patients were given yoga regimen for 3 months which consisted of yogic postures, pranayama breathing exercises, dietary modification, and holistic teaching along with their conventional medicine while Group II CAD patients were put only on conventional medicine. Lung functions including diffusion capacity were recorded thrice in both the groups: 0 day as baseline, 22(nd) day and on 90(th) day by using computerized MS medisoft Cardio-respiratory Instrument, HYP'AIR Compact model of cardio-respiratory testing machine was manufactured by P K Morgan, India. The recorded parameters were statistically analyzed by repeated measures ANOVA followed by Tukey's test in both the groups. Cardiovascular parameters were also compared before and after intervention in both the groups.

RESULTS

Statistically significant improvements were seen in slow vital capacity, forced vital capacity, peak expiratory flow rate, maximum voluntary ventilation, and diffusion factor/ transfer factor of lung for carbon monoxide after 3 months of yoga regimen in Group I. Forced expiratory volume in 1(st) sec (FEV1), and FEV1 % also showed a trend toward improvement although not statistically significant. HR, SBP and DBP also showed significant improvement in Group-I patients who followed yoga regimen.

CONCLUSIONS

Yoga regimen was found to improve lung functions and diffusion capacity in CAD patients besides improving cardiovascular functions. Thus, it can be used as a complimentary or adjunct therapy along with the conventional medicine for their treatment and rehabilitation.

Exercise training reduces cardiac dysfunction and remodeling in ovariectomized rats submitted to myocardial infarction

The aim of this study was to evaluate whether exercise training (ET) prevents or minimizes cardiac dysfunction and pathological ventricular remodeling in ovariectomized rats subjected to myocardial infarction (MI) and to examine the possible mechanisms involved in this process. Ovariectomized Wistar rats were subjected to either MI or fictitious surgery (Sham) and randomly divided into the following groups: Control, OVX+SHAM_SED, OVX+SHAM_ET, OVX+MI_SED and OVX+MI_ET. ET was performed on a motorized treadmill (5x/wk, 60 min/day, 8 weeks). Cardiac function was assessed by ventricular catheterization and Dihydroethidium fluorescence (DHE) was evaluated to analyze cardiac oxidative stress. Histological analyses were made to assess collagen deposition, myocyte hypertrophy and infarct size. Western Blotting was performed to analyze the protein expression of catalase and SOD-2, as well as Gp91phox and AT1 receptor (AT1R). MI-trained rats had significantly increased in +dP/dt and decreased left ventricular end-diastolic pressure compared with MI-sedentary rats. Moreover, oxidative stress and collagen deposition was reduced, as was myocyte hypertrophy. These effects occurred in parallel with a reduction in both AT1R and Gp91phox expression and an increase in catalase expression. SOD-2 expression was not altered. These results indicate that ET improves the functional cardiac parameters associated with attenuation of cardiac remodeling in ovariectomized rats subjected to MI. The mechanism seems to be related to a reduction in the expression of both the AT1 receptor and Gp91phox as well as an increase in the antioxidant enzyme catalase, which contributes to a reduction in oxidative stress. Therefore, ET may be an important therapeutic target for the prevention of heart failure in postmenopausal women affected by MI.

Exercise and risk of major cardiovascular events in adult survivors of childhood hodgkin lymphoma: a report from the childhood cancer survivor study

PURPOSE

Survivors of Hodgkin lymphoma (HL) are at increased risk of treatment-related cardiovascular (CV) events; whether exercise modifies this risk is unknown.

METHODS

Survivors of HL (n = 1,187; median age, 31.2 years) completed a questionnaire evaluating vigorous-intensity exercise behavior. CV events were collected in follow-up questionnaires and graded according to Common Terminology Criteria for Adverse Events (version 4.03). The primary end point was incidence of any major (grade 3 to 5) CV event. Poisson regression analyses were used to estimate the association between exercise exposure (metabolic equivalent [MET] hours/week(-1)) and risk of major CV events after adjustment for clinical covariates and cancer treatment.

RESULTS

Median follow-up was 11.9 years (range, 1.7 to 14.3 years). Cumulative incidence of any CV event was 12.2% at 10 years for survivors reporting 0 MET hours/week(-1) compared with 5.2% for those reporting ≥ 9 MET hours/week(-1). In multivariable analyses, the incidence of any CV event decreased across increasing MET categories (Ptrend = .002). Compared with survivors reporting 0 MET hours/week(-1), the adjusted rate ratio for any CV event was 0.87 (95% CI, 0.56 to 1.34) for 3 to 6 MET hours/week(-1), 0.45 (95% CI, 0.26 to 0.80) for 9 to 12 MET hours/week(-1), and 0.47 (95% CI, 0.23 to 0.95) for 15 to 21 MET hours/week(-1). Adherence to national vigorous intensity exercise guidelines (ie, ≥ 9 MET hours/week(-1)) was associated with a 51% reduction in the risk of any CV event in comparison with not meeting the guidelines (P = .002).

CONCLUSION

Vigorous exercise was associated with a lower risk of CV events in a dose-dependent manner independent of CV risk profile and treatment in survivors of HL.

Brachial artery characteristics and micro-vascular filtration capacity in rock climbers

Rock climbers perform repeated isometric forearm muscle contractions subjecting the vasculature to repeated ischaemia and distorted haemodynamic signals. This study investigated forearm vascular characteristics in rock climbers compared to healthy untrained controls. Eight climbers (CLIMB) (BMI; 22.3, s = 2.0 kg/m(2), isometric handgrip strength; 46, s = 8 kg) were compared against eight untrained controls (CON) (BMI; 23.8, s = 2.6 kg/m(2), isometric handgrip strength; 37, s = 9 kg). Brachial artery diameter and blood flow were measured, using Doppler ultrasound, at rest and following 5-mins ischaemia (peak diameter) and ischaemic exercise (maximal dilation) to calculate flow mediated dilation (FMD) and dilatory capacity (DC). Capillary filtration capacity was assessed using venous occlusion plethysmography. Resting (4.30, s = 0.26 vs. 3.79, s = 0.39 mm), peak (4.67, s = 0.31 vs. 4.12, s = 0.45 mm) and maximal (5.14, s = 0.42 vs. 4.35, s = 0.47 mm) diameters were greater (P < 0.05) in CLIMB than CON, respectively, despite no difference in FMD (9.2, s = 2.6 vs. 8.7, s = 2.9%). Peak reactive hyperaemic blood flow (1136, s = 504 vs. 651, s = 221 ml/min) and capillary filtration capacity (3.8, s = 0.9 vs. 5.2, s = 0.7 ml.min(-1).mmHg(-1).100 ml tissue(-1) × 10(-3)) were greater (P < 0.05) in CLIMB compared to CON, respectively. Rock climbers exhibit structural vascular adaptation compared to untrained control participants but have similar vascular function. This may contribute to the enhanced ability of climbers to perform repeated isometric contractions.

Effects of exercise training on circulating and skeletal muscle renin-angiotensin system in chronic heart failure rats

BACKGROUND

Accumulated evidence shows that the ACE-AngII-AT1 axis of the renin-angiotensin system (RAS) is markedly activated in chronic heart failure (CHF). Recent studies provide information that Angiotensin (Ang)-(1-7), a metabolite of AngII, counteracts the effects of AngII. However, this balance between AngII and Ang-(1-7) is still little understood in CHF. We investigated the effects of exercise training on circulating and skeletal muscle RAS in the ischemic model of CHF.

METHODS/MAIN RESULTS

Male Wistar rats underwent left coronary artery ligation or a Sham operation. They were divided into four groups: 1) Sedentary Sham (Sham-S), 2) exercise-trained Sham (Sham-Ex), sedentary CHF (CHF-S), and exercise-trained CHF (CHF-Ex). Angiotensin concentrations and ACE and ACE2 activity in the circulation and skeletal muscle (soleus and plantaris) were quantified. Skeletal muscle ACE and ACE2 protein expression, and AT1, AT2, and Mas receptor gene expression were also evaluated. CHF reduced ACE2 serum activity. Exercise training restored ACE2 and reduced ACE activity in CHF. Exercise training reduced plasma AngII concentration in both Sham and CHF rats and increased the Ang-(1-7)/AngII ratio in CHF rats. CHF and exercise training did not change skeletal muscle ACE and ACE2 activity and protein expression. CHF increased AngII levels in both soleus and plantaris muscle, and exercise training normalized them. Exercise training increased Ang-(1-7) in the plantaris muscle of CHF rats. The AT1 receptor was only increased in the soleus muscle of CHF rats, and exercise training normalized it. Exercise training increased the expression of the Mas receptor in the soleus muscle of both exercise-trained groups, and normalized it in plantaris muscle.

CONCLUSIONS

Exercise training causes a shift in RAS towards the Ang-(1-7)-Mas axis in skeletal muscle, which can be influenced by skeletal muscle metabolic characteristics. The changes in RAS circulation do not necessarily reflect the changes occurring in the RAS of skeletal muscle.

Effect of exercise training on left ventricular remodeling in diabetic patients with diastolic dysfunction: rationale and design

INTRODUCTION

This study will examine the effects of combined aerobic and resistance training on left ventricular remodeling in diabetic patients with diastolic dysfunction. This is the first randomized controlled trial to look for effects of combined strength training and aerobic exercise on myocardial function as well as other clinical, functional, or psychological parameters in diabetic patients with isolated diastolic dysfunction, and will provide important insights into the potential management strategies for heart failure with preserved ejection fraction.

METHODS AND ANALYSIS

This is a prospective, randomized controlled investigator initiated single center trial. Diabetic patients with LV diastolic dysfunction suitable for exercise training intervention will be randomized to three months of a supervised combination of aerobic and strength training exercises, or supervised light stretching (control arm). Pre and post intervention assessment will include stress echocardiography, peak aerobic power with 12-lead ECG, dual-energy X-ray absorptiometry, muscle strength, the capacity to perform activities of daily living (ADLs), and questionnaires to assess self-perceived quality of life and symptoms of depression. The primary endpoint is to compare any change in tissue Doppler-derived LV systolic and early diastolic velocities.

ETHICS AND DISSEMINATION

The current trial protocol has been approved by the Human Research Ethics Committee of Austin Health and the University of Melbourne, Melbourne. The study will be performed in accordance with the Declaration of Helsinki. The investigator, regardless of the outcome, will publish the results of the study.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12610000943044.

The role of B-type natriuretic Peptide testing in guiding outpatient heart failure treatment

OPINION STATEMENT

While heart failure (HF) treatment guidelines exist, there are significant gaps in their implementation owing in part to the lack of objective data to help guide clinicians in their medical decision-making. B-type natriuretic peptide (BNP) and its amino-terminal equivalent (NT-proBNP) are objective markers of HF prognosis, are useful to monitor response to treatment in outpatients with HF, and may have a role in "guiding" HF care as well. Successful BNP or NT-proBNP guided HF treatment requires regular attempts to reach and maintain target values (BNP ≤ 125 pg/mL or NT-proBNP ≤ 1000 pg/mL). This may be achieved through lifestyle modifications, exercise programs, medication adjustments, and therapeutic interventions shown to reduce morbidity and mortality in HF patients. Failure to achieve biomarker targets portends a worse prognosis, proportional to the lowest achieved natriuretic peptide concentration; in those with significant biomarker "nonresponse," prognosis is poor, and alternative therapeutic strategies should be considered.

Unraveling new mechanisms of exercise intolerance in chronic heart failure: role of exercise training

Despite remarkable progress in the therapeutic approach of patients with chronic heart failure (CHF), exercise intolerance remains one of the hallmarks of the disease. During the past two decades, evidence has accumulated to underscore the key role of both endothelial dysfunction and skeletal muscle wasting in the process that gradually leads to physical incapacity. Whereas reverse ventricular remodeling has been attributed to aerobic exercise training, the vast majority of studies conducted in this specific patient population emphasize the reversal of peripheral abnormalities. In this review, we provide a general overview on underlying pathophysiological mechanisms. In addition, emphasis is put on recently identified pathways, which contribute to a deeper understanding of the main causes of exercise tolerance and the potential for reversal through exercise training. Recently, deficient bone marrow-related endothelial repair mechanisms have received considerable attention. Both acute exercise bouts, as well as exercise training, affect the mobilization of endothelial progenitor cells and their function. The observed changes following exercise training are believed to significantly contribute to improvement of peripheral endothelial function, as well as exercise capacity. With regard to skeletal muscle dysfunction and energy deprivation, adiponectin has been suggested to play a significant role. The demonstration of local skeletal muscle adiponectin resistance may provide an interesting and new link between the insulin resistant state and skeletal muscle wasting in CHF patients.

Exercise and heart failure in the elderly

In this review, we will examine the physiological responses to exercise in elderly populations (age > 65 years) with and without evidence of heart failure. Aging per se in both men and women is associated with a ~40% lower maximum oxygen consumption in sedentary subjects. In trained individuals, this value is 25-32% lower. A smaller SV accounts for nearly 50% of these age-related differences, and the remainder is explained by a lower maximal HR and reduced oxygen extraction. Exercise training is also associated with an increase in the arteriovenous O(2) difference in previously sedentary elderly men and women, which probably contributes to the overall beneficial effect of training in the elderly. However, during vigorous exercise (125 W), the cardiac output in the elderly is dependent upon an age-related increase in end-diastolic volume and stroke volume, which "compensates" partially for the age-related decrease in heart rate. Hence, in elderly individuals, the stroke volume during exercise depends upon diastolic filling. The changes that occur in the heart are also associated with an overall reduction in efferent sympathetic nerve activity. Despite this decline, the metaboreflex initiated by receptors in exercising muscles remains the main determinant of sympathetic activation (to maintain blood pressure) during exercise in the elderly. It is recognized that aging is associated with the development of heart failure, particularly in women in whom its prevalence increases >twofold from age 65-69 (6.6%) to age 85 years (14%). Almost half the people presenting with heart failure appear to have normal left ventricular systolic function, a phenomenon that is more common in women. Exercise training in elderly people with and without heart failure appears to have a beneficial effect in terms of enhancing the quality of life and functional capacity. Mortality benefit in the latter has not been established with certainty.

Erectile dysfunction in heart failure patients: a critical reappraisal

Heart failure (HF) is a complex clinical syndrome with a constantly increasing incidence and prevalence in western countries. Total absence of sexual activity is registered in 30% of HF patients. Moreover, HF-induced reduction in exercise tolerance, side effects of HF medications and the coexistence of shared risk factors between HF and sexual dysfunction may further aggravate the sexual health of HF patients. The purpose of this review is to examine the pathophysiological mechanisms behind the association of erectile dysfunction (ED) and HF, the potential therapeutic approaches and the eventual indications for sexual activity in HF patients. Medline and Cochrane Library search was performed from January 1970 through October 2012 to retrieve relevant papers outlining the association between ED and HF. Many evidences have outlined a tight association between ED and HF pathophysiological standpoint. Shared risk factors, common pathogenic traits and epidemiologic association represent some of the links between these conditions. Erectile dysfunction has been recognized as an earlier predictor of cardiovascular events; moreover, HF itself may cause and/or worsen ED because of its particular feature and co-morbidities. Furthermore, some cardiovascular drugs may contribute to impaired erectile function. In stable patients with stable HF, sexual activity is generally not contraindicated but it should be encouraged, as a form of moderate-intensity physical exertion. An effective treatment of ED in HF patients should be founded on the correction of reversible risk factors, on the choice of cardiovascular drugs with the lowest effect upon patient's erectile function, and on the use of phosphodiesterase-5-inhibitors. Physicians should be aware of the close relation between HF and ED and of the related clinical and therapeutic implications, in order to improve patients quality of life and clinical outcome.

Exercise training in chronic heart failure: mechanisms and therapies

Decreased exercise capacity negatively affects the individuals' ability to adequately perform activities required for normal daily life and, therefore, the independence and quality of life. Regular exercise training is associated with improved quality of life and survival in healthy individuals and in cardiovascular disease patients. Also in patients with stable heart failure, exercise training can relieve symptoms, improve exercise capacity and reduce disability, hospitalisation and probably mortality. Physical inactivity can thus be considered a major cardiovascular risk factor, and current treatment guidelines recommend exercise training in patients with heart failure in NYHA functional classes II and III. Exercise training is associated with numerous pulmonary, cardiovascular, and skeletal muscle metabolic adaptations that are beneficial to patients with heart failure. This review discusses current knowledge of mechanisms by which exercise training is beneficial in these patients.

[Physical exercise training for cardiovascular diseases]

Clinical application of physical exercise has developed into an evidence-based therapeutic option for cardiovascular diseases, especially coronary artery disease (CAD) and chronic heart failure (CHF). In CAD regular physical exercise training partially corrects endothelial dysfunction and leads to an economization of left ventricular function. Meta-analyses have shown a reduction of angina pectoris symptoms and a decrease of total and cardiovascular mortality by regular aerobic exercise training. Endurance training for CHF reduces cardiac afterload by correcting peripheral endothelial dysfunction und leads to a better left ventricular function. In addition exercise training reduces the adrenergic tone and the stimulation of the renin-angiotensin-aldosterone system in CHF. Exercise training provides positive effects on the metabolism and function of skeletal muscle (e.g. reduced inflammation and oxidative stress). Supervised regular physical exercise training in CHF is safe and has improved the morbidity in clinical studies. Thus aerobic exercise training is an important component of therapeutic management of stable CAD and CHF with a class 1a recommendation in the current guidelines.

Endurance exercise in a rat model of metabolic syndrome

We have measured the responses to endurance exercise training on body composition and glucose regulation, as well as cardiovascular and liver structure and function in rats fed a high carbohydrate and high fat (HCHF) diet as a model of human metabolic syndrome. Male Wistar rats (9-10 weeks old) were randomly allocated into corn starch (CS) or HCHF diet groups for 16 weeks; half of each group were exercised on a treadmill for 20, 25, and then 30 min/day, 5 days/week, during the last 8 weeks of the protocol. Metabolic, cardiovascular, and liver parameters were monitored. The HCHF diet induced symptoms of metabolic syndrome, including obesity, dyslipidemia, impaired glucose tolerance, and increased systolic blood pressure associated with the development of cardiovascular remodeling and nonalcoholic steatohepatitis. Exercise in HCHF rats decreased body mass, abdominal fat pads and circumference, blood glucose concentrations, plasma lipid profiles, systolic blood pressure, left ventricular diastolic stiffness, collagen deposition and inflammatory cell infiltration in the left ventricle, improved aortic contractile and relaxation responses, and decreased liver mass and hepatic fat accumulation. This study demonstrates that endurance exercise is effective in this rat model of diet-induced metabolic syndrome in improving body composition and glucose regulation, as well as cardiovascular and liver structure and function.

Relation between volume of exercise and clinical outcomes in patients with heart failure

OBJECTIVES

This study determined whether greater volumes of exercise were associated with greater reductions in clinical events.

BACKGROUND

The HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) trial showed that among patients with heart failure (HF), regular exercise confers a modest reduction in the adjusted risk for all-cause mortality or hospitalization.

METHODS

Patients randomized to the exercise training arm of HF-ACTION who were event-free at 3 months after randomization were included (n = 959). Median follow-up was 28.2 months. Clinical endpoints were all-cause mortality or hospitalization and cardiovascular mortality or HF hospitalization.

RESULTS

A reverse J-shaped association was observed between exercise volume and adjusted clinical risk. On the basis of Cox regression, exercise volume was not a significant linear predictor but was a logarithmic predictor (p = 0.03) for all-cause mortality or hospitalization. For cardiovascular mortality or HF hospitalization, exercise volume was a significant (p = 0.001) linear and logarithmic predictor. Moderate exercise volumes of 3 to <5 metabolic equivalent (MET)-h and 5 to <7 MET-h per week were associated with reductions in subsequent risk that exceeded 30%. Exercise volume was positively associated with the change in peak oxygen uptake at 3 months (r = 0.10; p = 0.005).

CONCLUSIONS

In patients with chronic systolic HF, volume of exercise is associated with the risk for clinical events, with only moderate levels (3 to 7 MET-h per week) of exercise needed to observe a clinical benefit. Although further study is warranted to confirm the relationship between volume of exercise completed and clinical events, our findings support the use of regular exercise in the management of these patients.