Aerobic exercise training intensity in patients with chronic heart failure: principles of assessment and prescription

Ergophysiological evaluation of heart failure patients with reduced ejection fraction undergoing exercise-based cardiac rehabilitation: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aims to explore in heart failure (HF) patients with reduced ejection fraction (EF) undergoing exercise-based cardiac rehabilitation the following: 1) the comparison of temporal changes between peak oxygen uptake (VO2peak) and first ventilatory threshold (VO2VT1), 2) the association of VO2peak and VO2VT1 changes with physiological factors, and 3) the differential effects of continuous aerobic exercise (CAE) and interval training (IT) on VO2peak and VO2VT1.

METHODS

A systematic literature search was conducted in PubMed, CENTRAL, and Scopus. Inclusion criteria were 1) original research articles using exercise-based cardiac rehabilitation, 2) stable HF patients with reduced EF, 3) available values of VO2peak and VO2VT1 (in mL/kg/min) both at baseline and after exercise training with comparison between these time points.

RESULTS

Among the 30 eligible trials, 24 used CAE, 5 IT, and one CAE and IT. Multivariable meta-regression with duration of exercise training and percentage of males as independent variables and the change in VO2peak as a dependent variable showed that the change in VO2peak was negatively associated with duration of exercise training (coefficient=-0.061, p=0.027), implying the possible existence of a waning effect of exercise training on VO2peak in the long term. Multivariable meta-regression demonstrated that both age (coefficient=-0.140, p<0.001) and EF (coefficient=-0.149, p<0.001) could predict the change in VO2VT1, whereas only age (coefficient=-0.095, p=0.022), but not EF (coefficient = 0.082, p = 0.100), could predict the change in VO2peak. The posttraining peak respiratory exchange ratio, as an index of maximum effort during exercise testing, correlated positively with the change in VO2peak (coefficient=-0.021, p=0.044). The exercise-induced changes of VO2peak (p = 0.438) and VO2VT1 (p = 0.474) did not differ between CAE and IT groups.

CONCLUSIONS

Improvement of endurance capacity during cardiac rehabilitation may be detected more accurately with the assessment of VO2VT1 rather than VO2peak.

Borg's exertion scale did not coincide with ventilatory anaerobic threshold in atrial fibrillation patients with restored sinus rhythm after ablation

The determination of precise exercise intensity is essential for effective exercise rehabilitation. The Borg rating of perceived exertion category ratio (CR) scale is utilized to prescribe an appropriate level of exertion intensity. A Borg CR of approximately 13 coincides with the ventilatory aerobic threshold (VAT). Patients with atrial fibrillation (AF) exhibit various symptoms. We hypothesized that the workload at Borg CR13 (Borg CR13-Watt) differs from the workload at the VAT level (VAT-Watt) in AF patients with restored sinus rhythm (SR) following ablation. Accordingly, the relationship between Borg CR13-Watt and VAT-Watt was studied in patients with restored SR. Cardiopulmonary exercise testing (CPET) was performed at 101±88 days after ablation in 150 patients using a bicycle ergometer. No adverse events were observed during CPET. Borg CR13-Watt was significantly higher than VAT-Watt (67.2±27.8 Watt vs. 54.7±17.6 Watt, P<0.0001). Borg CR13-Watt showed significant linear regression with VAT-Watt (regression coefficient, 0.49, P<0.01; correlation coefficient, 0.80, P<0.01). Higher Borg CR13-Watt was associated with greater differences between Borg CR13-Watt and VAT-Watt (ΔWatt). The Bland-Altman plot showed nonconcordance between the two. Male sex, use of antiarrhythmic drugs, and smoking had contributed to the increased ΔWatt. Duration from ablation to time of CPET did not correlate with ΔWatt. Therefore, Borg CR13-Watt did not coincide with VAT-Watt in patients with restored SR. Higher Borg CR13-Watt was associated with greater ΔWatt. Prescribing exertion intensity as determined solely by perceived exertion is inadequate. CPET is required to determine the precise exercise intensity in AF patients with restored SR after ablation.

Standardised Exercise Prescription for Patients with Chronic Coronary Syndrome and/or Heart Failure: A Consensus Statement from the EXPERT Working Group

Whereas exercise training, as part of multidisciplinary rehabilitation, is a key component in the management of patients with chronic coronary syndrome (CCS) and/or congestive heart failure (CHF), physicians and exercise professionals disagree among themselves on the type and characteristics of the exercise to be prescribed to these patients, and the exercise prescriptions are not consistent with the international guidelines. This impacts the efficacy and quality of the intervention of rehabilitation. To overcome these barriers, a digital training and decision support system [i.e. EXercise Prescription in Everyday practice & Rehabilitative Training (EXPERT) tool], i.e. a stepwise aid to exercise prescription in patients with CCS and/or CHF, affected by concomitant risk factors and comorbidities, in the setting of multidisciplinary rehabilitation, was developed. The EXPERT working group members reviewed the literature and formulated exercise recommendations (exercise training intensity, frequency, volume, type, session and programme duration) and safety precautions for CCS and/or CHF (including heart transplantation). Also, highly prevalent comorbidities (e.g. peripheral arterial disease) or cardiac devices (e.g. pacemaker, implanted cardioverter defibrillator, left-ventricular assist device) were considered, as well as indications for the in-hospital phase (e.g. after coronary revascularisation or hospitalisation for CHF). The contributions of physical fitness, medications and adverse events during exercise testing were also considered. The EXPERT tool was developed on the basis of this evidence. In this paper, the exercise prescriptions for patients with CCS and/or CHF formulated for the EXPERT tool are presented. Finally, to demonstrate how the EXPERT tool proposes exercise prescriptions in patients with CCS and/or CHF with different combinations of CVD risk factors, three patient cases with solutions are presented.

Practical guidelines for exercise prescription in patients with chronic heart failure

Chronic heart failure (HF) is a major cause of morbidity, mortality, disability, and health care costs. A hallmark feature of HF is severe exercise intolerance, which is multifactorial and stems from central and peripheral pathophysiological mechanisms. Exercise training is internationally recognized as a Class 1 recommendation for patients with HF, regardless of whether ejection fraction is reduced or preserved. Optimal exercise prescription has been shown to enhance exercise capacity, improve quality of life, and reduce hospitalizations and mortality in patients with HF. This article will review the rationale and current recommendations for aerobic training, resistance training, and inspiratory muscle training in patients with HF. Furthermore, the review provides practical guidelines for optimizing exercise prescription according to the principles of frequency, intensity, time (duration), type, volume, and progression. Finally, the review addresses common clinical considerations and strategies when prescribing exercise in patients with HF, including considerations for medications, implantable devices, exercise-induced ischemia, and/or frailty.

Nurse-coordinated home-based cardiac rehabilitation for patients with heart failure: A scoping review

Objectives

This study aimed to review and summarize the studies of nurse-coordinated home-based cardiac rehabilitation for patients with heart failure.

Methods

The review was performed using Arksey and O'Malley's scoping review framework. A systematic search was conducted across eight databases, including PubMed, Embase, Web of Science, EBSCO, China Biomedical Literature Service System (SinoMed), China National Knowledge Infrastructure (CNKI), Wanfang Database, and Chinese Science and Technology Journals (CSTJ) Database, and Chinese Clinical Trial Registry, from inception to 30 April 2023. Articles relevant to the nurse-coordinated home-based cardiac rehabilitation for patients with heart failure were included.

Results

Eighteen studies were included in this review. These studies showed that nurses primarily focused on patient assessment, home-based cardiac rehabilitation planning and guidance, and follow-up. The studies also reported positive outcomes in patient safety, feasibility, and efficacy of the programs coordinated by nurses.

Conclusions

Home-based cardiac rehabilitation coordinated by nurses is beneficial to patients with heart failure. Future research will explore the potential of nurses in home-based cardiac rehabilitation for patients with heart failure, determine optimal evaluation criteria, and formulate safe, effective, and economical rehabilitation programs suitable for the patients.

Different Continuous Training Intensities Improve Echocardiographic Parameters, Quality of Life, and Functional Capacity in Heart Failure Patients with Reduced Ejection Fraction

Background

Multiple comorbidities and physiological changes play a role in a range of heart failure conditions and influence the most effective approach to exercise-based rehabilitation. This research aimed to examine and compare the outcomes of continuous training at three different intensities, focusing on left ventricular (LV) remodeling, functional capacity, and quality of life among patients with heart failure with reduced ejection fraction (HFrEF).

Methods

In this randomized control trial, a total of 60 male patients (average age: 54.33 ±2.35 years) with HFrEF were randomly allocated into three groups: 1) High-intensity continuous training group (HICT), 2) Moderate-intensity continuous training group (MICT), and 3) Low-intensity continuous training group (LICT). All the training was performed on a bicycle ergometer 3 times/week for 12 weeks. Echocardiographic parameters (left ventricular ejection fraction, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, N-terminal pro-B-type natriuretic peptide (NT-proBNP), quality of life (Minnesota Living with Heart Failure Questionnaire), and functional capacity (6-minute walking test) were assessed before and the end of the study.

Results

The HICT group demonstrated the greatest improvements in all measured variables when compared to the other two groups (P < 0.05). These findings were consistent across all measured outcomes.

Conclusion

It was determined that HICT appears to yield the most favorable outcomes in enhancing echocardiographic measures, NT-proBNP levels, quality of life, and functional capacity among HFrEF patients.

Consistency evaluation of exercise target heart rate determined by resting heart rate and anaerobic threshold in chronic heart failure patients

PURPOSE

To evaluate the consistency on the target heart rate for exercise determined by simple target heart rate (sTHR) based on resting heart rate (HRrest) and heart rate at anaerobic threshold (HRAT) in cardiopulmonary exercise test (CPET) for patients with chronic heart failure.

METHODS

This is a retrospective cohort study, in which CHF patients who underwent CPET in Tongji Hospital Cardiac Rehabilitation Center Affiliated to Tongji University from March 2007 to December 2018 were enrolled. The clinical data of the patients from the electronic medical record system, HRrest and HRAT measured by CPET were collected. Patients were further divided into subgroups according to gender, age (<60 years group and ≥ 60 years group), with or without beta-blocker therapy and subgroup of heart failure (heart failure with reduced, mid-range and preserved ejection fraction). The sTHR (HRrest plus 10, 15, 20, 25 and 30 bpm) and HRAT were all calculated in each patient. Paired t-test was used for the difference between the two methods, correlation analysis was shown by pearson analysis and intraclass correlation coefficient (ICC) was calculated for consistency test.

RESULTS

A total of 547 CHF patients were enrolled, including 447 males (81.7%), aged 63 (56,69) years, with BMI of 25.2 (23.5,26.4) kg/m² and LVEF of 45.0 (36.0, 52.0) %. The target heart rate determined by HRAT method was (93.59 ± 13.95) bpm, and its counterpart determined by HRrest plus 20 bpm (HRrest₊₂₀) was (93.16 ± 7.69) bpm. There was no significant difference between the two methods (P>0.05). However, it was statistically different between HRrest plus 10, 15, 25, 30 bpm and HRAT respectively (P<0.001). And HRrest₊₂₀ was positively correlated with HRAT (r = 0.418, P<0.001). Therefore, HRrest₊₂₀ below was regarded as sTHR. The ICC of the consistency test between sTHR and HRAT was 0.523,95%CI 0.435-0.596 (P < 0.001) in all patients (n = 547). In patients with beta-blocker therapy (n = 464), the ICC of sTHR and HRAT consistency test was 0.534,95%CI 0.441-0.612, P < 0.001; The ICC of the consistency test between sTHR and HRAT of patients without beta-blocker therapy (n = 83) was 0.407,95%CI 0.083-0.616, P < 0.05. In the sinus rhythm group (n = 466), the ICC of sTHR and HRAT consistency test was 0.527,95%CI 0.433-0.606, P < 0.001; The ICC of the consistency test between sTHR and HRAT of atrial fibrillation patients in group (n = 81) was 0.482,95%CI 0.195-0.667, P < 0.05.The ICC of the consistency test between sTHR and HRAT was 0.501,95%CI 0.338-0.623 (P < 0.001) in patients under 60 years old (n = 195); The ICC of the consistency test between sTHR and HRAT in patients ≥60 years old (n = 352) was 0.533,95%CI 0.424-0.621, P < 0.001. In the male group (n = 447), the ICC of sTHR and HRAT consistency test was 0.577,95%CI 0.491-0.649, P < 0.001; The ICC of the consistency test between sTHR and HRAT of female patients in group (n = 100) was 0.344,95%CI 0.025-0.559, P < 0.05. The ICC of sTHR and HRAT consistency test in HFrEF group (n = 170) was 0.395,95%CI 0.181-0.553, P < 0.01; The ICC values of the consistency test between sTHR and HRAT was 0.543, 95%CI 0.405-0.649 (P < 0.001) in patients with HFmrEF (n = 222); In HFpEF group (n = 155), the ICC of sTHR and HRAT consistency test was 0.620,95%CI 0.478-0.723, P < 0.001.

CONCLUSION

The exercise target heart rate calculated by HRrest is consistent with that determined by HRAT in patients with CHF. For primary hospitals without CPET, exercise prescription equivalent to AT intensity for patients with CHF can be determined by HRrest. However, the target heart rate calculated by HRrest can't replace that determined by HRAT in this patient cohort completely.

Effects of continuous aerobic training associated with resistance training on maximal and submaximal exercise tolerance, fatigue, and quality of life of patients post-COVID-19

BACKGROUND AND PURPOSE

Dyspnea, fatigue, and reduced exercise tolerance are common in post-COVID-19 patients. In these patients, rehabilitation can improve functional capacity, reduce deconditioning after a prolonged stay in the intensive care unit, and facilitate the return to work. Thus, the present study verified the effects of cardiopulmonary rehabilitation consisting of continuous aerobic and resistance training of moderate-intensity on pulmonary function, respiratory muscle strength, maximum and submaximal tolerance to exercise, fatigue, and quality of life in post-COVID-19 patients.

METHODS

Quasi-experimental study with a protocol of 12 sessions of an outpatient intervention. Adults over 18 years of age (N = 26) with a diagnosis of COVID-19 and hospital discharge at least 15 days before the first evaluation were included. Participants performed moderate-intensity continuous aerobic and resistance training twice a week. Maximal and submaximal exercise tolerance, lung function, respiratory muscle strength, fatigue and quality of life were evaluated before and after the intervention protocol.

RESULTS

Cardiopulmonary rehabilitation improved maximal exercise tolerance, with 18.62% increase in peak oxygen consumption (VO2peak) and 29.05% in time to reach VO2 peak. VE/VCO2 slope reduced 5.21% after intervention. We also observed increased submaximal exercise tolerance (increase of 70.57 m in the 6-min walk test, p = 0.001), improved quality of life, and reduced perceived fatigue after intervention.

DISCUSSION

Patients recovered from COVID-19 can develop persistent dysfunctions in almost all organ systems and present different signs and symptoms. The complexity and variability of the damage caused by this disease can make it difficult to target rehabilitation programs, making it necessary to establish specific protocols. In this work, cardiopulmonary rehabilitation improved lung function, respiratory muscle strength, maximal and submaximal exercise tolerance, fatigue and quality of life. Continuous aerobic and resistance training of moderate intensity proved to be effective in the recovery of post-COVID-19 patients.

The Effect of Aquatic Exercise Training on Heart Rate Variability in Patients with Coronary Artery Disease

(1) Background: Aquatic exercise training is a relatively understudied exercise modality in patients with CAD; with the present study, we sought to compare the impact of short-term 14-day water- and land-based exercise training on heart rate variability (HRV). (2) Methods: We randomized 90 patients after a recent CAD event (myocardial infarction and/or revascularization within 2 months prior to inclusion) to either (i) water-based or (ii) land-based exercise training (14 days, two 30 min sessions daily), or (iii) controls. Before and after the intervention period, all participants underwent 20 min 12-channel high-resolution ECG recordings with off-line HRV analysis, including conventional linear time- and frequency-domain analysis (using the Welch method for fast-Fourier transformation), and preselected non-linear analysis (Poincaré plot-derived parameters, sample entropy, and the short-term scaling exponent α1 obtained by detrended fluctuation analysis). (3) Results: Eighty-nine patients completed the study (mean age 60 ± 8 years; 20 % women). We did not detect significant differences in baseline- or age-adjusted end-of-study HRV parameters, but aquatic exercise training was associated with a significant increase in the linear LF/HF parameter (from 2.6 [1.2–4.0] to 3.0 [2.1–5.5], p = 0.046) and the non-linear α1 parameter (from 1.2 [1.1–1.4] to 1.3 [1.2–1.5], p = 0.043). (4) Conclusions: Our results have shown that a short-term 14-day aquatic exercise training program improves selected HRV parameters, suggesting this mode of exercise is safe and may be beneficial in patients with CAD.

Optimizing Outcomes in Cardiac Rehabilitation: The Importance of Exercise Intensity

Exercise based cardiac rehabilitation (CR) is recognized internationally as a class 1 clinical practice recommendation for patients with select cardiovascular diseases and heart failure with reduced ejection fraction. Over the past decade, several meta-analyses have generated debate regarding the effectiveness of exercise-based CR for reducing all-cause and cardiovascular mortality. A common theme highlighted in these meta-analyses is the heterogeneity and/or lack of detail regarding exercise prescription methodology within CR programs. Currently there is no international consensus on exercise prescription for CR, and exercise intensity recommendations vary considerably between countries from light-moderate intensity to moderate intensity to moderate-vigorous intensity. As cardiorespiratory fitness [peak oxygen uptake (VO₂peak)] is a strong predictor of mortality in patients with coronary heart disease and heart failure, exercise prescription that optimizes improvement in cardiorespiratory fitness and exercise capacity is a critical consideration for the efficacy of CR programming. This review will examine the evidence for prescribing higher-intensity aerobic exercise in CR, including the role of high-intensity interval training. This discussion will highlight the beneficial physiological adaptations to pulmonary, cardiac, vascular, and skeletal muscle systems associated with moderate-vigorous exercise training in patients with coronary heart disease and heart failure. Moreover, this review will propose how varying interval exercise protocols (such as short-duration or long-duration interval training) and exercise progression models may influence central and peripheral physiological adaptations. Importantly, a key focus of this review is to provide clinically-relevant recommendations and strategies to optimize prescription of exercise intensity while maximizing safety in patients attending CR programs.

Aerobic Threshold Identification in a Cardiac Disease Population Based on Correlation Properties of Heart Rate Variability

An index of heart rate (HR) variability correlation properties, the short-term scaling exponent alpha1 of detrended fluctuation analysis (DFA a1) has shown potential to delineate the first ventilatory threshold (VT1). This study aims to extend this concept to a group of participants with cardiac disease. Sixteen volunteers with stable coronary disease or heart failure performed an incremental cycling ramp to exhaustion PRE and POST a 3-week training intervention. Oxygen uptake (VO₂) and HR at VT1 were obtained from a metabolic cart. An ECG was processed for DFA a1 and HR. The HR variability threshold (HRVT) was defined as the VO₂, HR or power where DFA a1 reached a value of 0.75. Mean VT1 was reached at 16.82 ± 5.72 mL/kg/min, HR of 91.3 ± 11.9 bpm and power of 67.8 ± 17.9 watts compared to HRVT at 18.02 ± 7.74 mL/kg/min, HR of 94.7 ± 14.2 bpm and power of 73.2 ± 25.0 watts. Linear relationships were seen between modalities, with Pearson’s r of 0.95 (VO₂), 0.86 (HR) and 0.87 (power). Bland–Altman assessment showed mean differences of 1.20 mL/kg/min, 3.4 bpm and 5.4 watts. Mean peak VO₂ and VT1 did not change after training intervention. However, the correlation between PRE to POST change in VO₂ at VT1 with the change in VO₂ at HRVT was significant (r = 0.84, p < 0.001). Reaching a DFA a1 of 0.75 was associated with the VT1 in a population with cardiac disease. VT1 change after training intervention followed that of the HRVT, confirming the relationship between these parameters.

Exercise-Intensity Adherence During Aerobic Training and Cardiovascular Response During Resistance Training in Cancer Survivors

ABSTRACT

Quevedo-Jerez, K, Gil-Rey, E, Maldonado-Martín, S, and Herrero-Román, F. Exercise-intensity adherence during aerobic training and cardiovascular response during resistance training in cancer survivors. J Strength Cond Res 35(8): 2338-2345, 2021-Combined aerobic-resistance training has shown the best benefits has proved beneficial for cancer survivors (CS). To understand the adherence to the aerobic training program (in terms of the intensity and duration of the sessions) and the cardiovascular response to the resistance training program, heart rate (HR) of 48 CS was monitored in each training session with an HR monitor for a 2-year period. During aerobic training, CS had to maintain the intensity in zone 2 (Z2) (between the ventilatory threshold and respiratory compensation point). The time spent below Z2 (Z1), in Z2, and above Z2 (Z3) was assessed in both aerobic and resistance training. The exercise-intensity distribution (aerobic vs. resistance training) was as follows: Z1 6.6 ± 12.8% vs. 34.3 ± 29.9% (p < 0.001); Z2 66.6 ± 29.3% vs. 54.5 ± 27.6% (p < 0.05); and Z3 26.9 ± 29.9% vs. 11.2 ± 20.6% (p < 0.001). The most deconditioned CS (<4.5 metabolic equivalents [METs]) presented the poorest adherence in Z2 and spent the most time in Z3. A significant positive moderate-high correlation was found for the percentage of time in Z3 between resistance and aerobic exercise (r = 0.75, p < 0.001). In conclusion, the individualization of exercise intensity resulted in good adherence to the prescribed intensity. Less fit CS needed more supervision in their training sessions. Resistance training allowed the CS to train in moderate-vigorous intensities of cardiovascular response. Resistance training should have more scope in exercise prescriptions, particularly in deconditioned CS and in the first steps of exercise programs.

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.

Comparative effectiveness of exercise training program in patients with heart failure: protocol for a systematic review of randomised controlled trials and network meta-analysis

INTRODUCTION

Heart failure (HF) is an end-stage of numerous heart diseases including hypertension, coronary heart disease and arrhythmia, in which the heart is unable to perform its circulatory function with sufficient efficiency due to structural or functional dysfunction (systolic or diastolic alterations). Strategies such as exercise rehabilitation may improve cardiac function, exercise capacity and health-related quality of life and reduce anxiety and depression in patients with HF. However, the relative effectiveness as well as the hierarchy of exercise interventions have not been well established, although various exercise options are available. Therefore, this protocol proposes to conduct a network meta-analysis (NMA) aiming to compare the effectiveness of different types of exercise training in patients with HF.

METHODS AND ANALYSIS

PubMed, Embase and the Cochrane Library will be searched from inception to March 2021 for relevant randomised controlled trials. Other resources, such as Google Scholar and Clinical Trials.gov will also be considered. Studies assessing exercise rehabilitation in patients with HF will be selected. Two independent reviewers will identify eligible trials. The PEDro risk of bias assessment tool will be used to assess the quality of the included studies. Bayesian NMA will be used when possible to determine the comparative effectiveness of the different exercise interventions. The mean ranks and surface will estimate the ranking probabilities for the optimal intervention of various treatments under the cumulative ranking curve. Subgroup, sensitivity and meta-regression will be conducted to explain the included studies' heterogeneity if possible. We will also use the Grading of Recommendations, Assessment, Development, and Evaluation system to assess the strength of evidence.

ETHICS AND DISSEMINATION

This systematic review and NMA will synthesise evidence on the effectiveness of the different exercises in patients with HF. The results will be submitted to a peer-reviewed journal. No ethical approval will be required because the data used for the review will be exclusively extracted from published studies.

PROSPERO REGISTRATION NUMBER

CRD42020165870.

Prescribing, dosing and titrating exercise in patients with hypertrophic cardiomyopathy for prevention of comorbidities: Ready for prime time

The benefits of physical activity are well established, leading to both cardiovascular and non-cardiovascular benefits, improving quality of life and reducing mortality. Despite such striking body of evidence, patients with hypertrophic cardiomyopathy are often discouraged by health professionals to practice physical activity and personalised exercise prescription is an exception rather than the rule. As a result, hypertrophic cardiomyopathy patients are on average less active and spend significantly less time at work or recreational physical activity than the general population. Exercise restriction derives from the evidence that vigorous exercise may occasionally trigger life-threatening arrhythmias and sudden cardiac death. However, while participation in competitive sports should be prudentially denied, hypertrophic cardiomyopathy patients can benefit from the positive effects of regular physical activity, aimed to reduce the risk of comorbidities and improve the quality of life. Based on this rationale, exercise should be prescribed and titrated just like a drug in hypertrophic cardiomyopathy patients, considering individual characteristics, symptoms, past medical history, objective individual response to exercise, previous training experience and stage of disease. Type, frequency, duration, and intensity should be defined on a personal basis. Yet exercise prescription in hypertrophic cardiomyopathy and its long-term effects represent major gaps in our current knowledge and require extensive research. We here review existing evidence regarding benefits and hazards of physical activity, with specific focus on viable modalities for tailored and safe exercise prescription in these patients, highlighting future developments and relevant research targets.

Impact of a Supervised Twelve-Week Combined Physical Training Program in Heart Failure Patients: A Randomized Trial

Purpose

The aim of this study was to compare the effects of supervised combined physical training and unsupervised physician-prescribed regular exercise on the functional capacity and quality of life of heart failure patients.

Methods

This is a longitudinal prospective study composed of 28 consecutive heart failure with reduced ejection fraction patients randomly divided into two age- and gender-matched groups: trained group (n = 17) and nontrained group (n = 11). All patients were submitted to clinical evaluation, transthoracic echocardiography, the Cooper walk test, and a Quality of Life questionnaire before and after a 12-week study protocol. Categorical variables were expressed as proportions and compared with the chi-square test. Two-way ANOVA was performed to compare the continuous variables considering the cofactor groups and time of intervention, and Pearson correlation tests were conducted for the associations in the same group.

Results

No significant differences between groups were found at baseline. At the end of the protocol, there were improvements in the functional capacity and ejection fraction of the trained group in relation to the nontrained group (p < 0.05). There was time and group interaction for improvement in the quality of life in the trained group.

Conclusions

In patients with heart failure with reduced ejection fraction, supervised combined physical training improved exercise tolerance and quality of life compared with the unsupervised regular exercise prescribed in routine medical consultations. Left ventricular systolic function was improved with supervised physical training.

2019 EACTS Expert Consensus on long-term mechanical circulatory support

Long-term mechanical circulatory support (LT-MCS) is an important treatment modality for patients with severe heart failure. Different devices are available, and many-sometimes contradictory-observations regarding patient selection, surgical techniques, perioperative management and follow-up have been published. With the growing expertise in this field, the European Association for Cardio-Thoracic Surgery (EACTS) recognized a need for a structured multidisciplinary consensus about the approach to patients with LT-MCS. However, the evidence published so far is insufficient to allow for generation of meaningful guidelines complying with EACTS requirements. Instead, the EACTS presents an expert opinion in the LT-MCS field. This expert opinion addresses patient evaluation and preoperative optimization as well as management of cardiac and non-cardiac comorbidities. Further, extensive operative implantation techniques are summarized and evaluated by leading experts, depending on both patient characteristics and device selection. The faculty recognized that postoperative management is multidisciplinary and includes aspects of intensive care unit stay, rehabilitation, ambulatory care, myocardial recovery and end-of-life care and mirrored this fact in this paper. Additionally, the opinions of experts on diagnosis and management of adverse events including bleeding, cerebrovascular accidents and device malfunction are presented. In this expert consensus, the evidence for the complete management from patient selection to end-of-life care is carefully reviewed with the aim of guiding clinicians in optimizing management of patients considered for or supported by an LT-MCS device.

Short-Term Water- and Land-Based Exercise Training Comparably Improve Exercise Capacity and Vascular Function in Patients After a Recent Coronary Event: A Pilot Randomized Controlled Trial

Background

We hypothesized that a 2-week twice daily aquatic endurance plus calisthenics exercise training program: (i) increases aerobic exercise capacity (peak oxygen uptake/ V ˙ O₂peak), (ii) improves endothelium-dependent flow-mediated vasodilation (FMD), and (iii) reduces circulating markers of low-grade inflammation and hemostasis, as compared to land-based endurance plus calisthenics exercise training or no exercise in patients undergoing short-term residential cardiac rehabilitation after a recent coronary artery disease (CAD) event.

Methods

Patients with a recent myocardial infarction or revascularization procedure were randomized into two interventional groups and a control group. The interventional groups underwent supervised aerobic endurance plus calisthenics exercise training either in thermo-neutral water or on land at moderate intensity (60-80% of the peak heart rate achieved during symptom-limited graded exercise testing) for 30 min twice daily for 2 weeks (i.e., 24 sessions). The control group was deferred from supervised exercise training for the 2-week duration of the intervention, but was advised low-to-moderate intensity physical activity at home while waiting. At baseline and after the intervention period, all participants underwent estimation of aerobic exercise capacity, brachial artery flow-mediated dilatation (FMD, measured ultrasonographically at rest and during reactive hyperemia after 4.5 min of forearm cuff inflation), markers of cardiac dysfunction (NT-proBNP), inflammation (hsCRP, IL-6, IL-8, IL-10), cell adhesion (ICAM, P-selectin), and hemostasis (fibrinogen, D-dimer).

Results

A total of 89 patients (mean age 59.9 ± 8.2 years, 77.5% males, V ˙ O₂peak at baseline 14.8 ± 3.5 ml kg^-1 min^-1) completed the study. Both exercise modalities were safe (no significant adverse events recorded) and associated with a significant improvement in V ˙ O₂peak as compared to controls: age and baseline V ˙ O₂peak-adjusted end-of-study V ˙ O₂peak increased to 16.7 (95% CI 16.0-17.4) ml kg^-1 min^-1 with land-based training (p < 0.001 for change from baseline) and to 18.6 (95% CI 17.9-19.3) ml kg^-1 min^-1 with water-based training (p < 0.001 for change from baseline), but not in controls (14.9 ml kg^-1 min^-1; 95% CI 14.2-15.6; p = 0.775 for change from baseline). FMD also increased in both intervention groups (from 5.5 to 8.8%, p < 0.001 with land-based, and from 7.2 to 9.2%, p < 0.001 with water-based training, respectively), as compared to controls (p for change 0.629). No significant changes were detected in biomarkers of inflammation, cell adhesion or hemostasis, whereas levels of NT-proBNP (marker of cardiac dysfunction) decreased in the water-based training group (p = 0.07 vs. controls).

Conclusion

Endurance plus calisthenics exercise training in thermo-neutral water is safe, and improves aerobic exercise capacity and vascular function in patients undergoing short-term residential cardiac rehabilitation after a recent CAD event.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT02831829.

Home-based cardiac rehabilitation improves quality of life, aerobic capacity, and readmission rates in patients with chronic heart failure

BACKGROUND

Exercise tolerance and cardiac output have a major impact on the quality of life (QOL) of patients experiencing heart failure (HF). Home-based cardiac rehabilitation can significantly improve not only exercise tolerance but also peak oxygen uptake ((Equation is included in full-text article.)peak), and the QOL in patients with HF. The aim of this prospective study was to evaluate the beneficial effects of home-based cardiac rehabilitation on the quality of medical care in patients with chronic HF.

METHODS

This study was a randomized prospective trial. HF patients with a left ventricular ejection fraction (LVEF) of less than 50% were included in this study. We randomly assigned patients to the control group (n = 18) and the interventional group (n = 19). Within the interventional group, we arranged individualized rehabilitation programs, including home-based cardiac rehabilitation, diet education, and management of daily activity over a 3-month period. Information such as general data, laboratory data, Cardiopulmonary Exercise Test (CPET) results, Six-minute Walk Test (6MWT) results, and the scores for the Minnesota Living with Heart Failure Questionnaire (MLHFQ) before and after the intervention, was collected from all patients in this study.

RESULTS

Patients enrolled in the home-based cardiac rehabilitation programs displayed statistically significant improvement in (Equation is included in full-text article.)peak (18.2 ± 4.1 vs 20.9 ± 6.6 mL/kg/min, P = .02), maximal 6-Minute Walking Distance (6MWD) (421 ± 90 vs 462 ± 74 m, P = .03), anaerobic threshold (12.4 ± 2.5 vs 13.4 ± 2.6 mL/kg/min, P = .005), and QOL. In summary, patients receiving home-based cardiac rehabilitation experienced a 14.2% increase in (Equation is included in full-text article.)peak, a 37% increase in QOL score, and an improvement of 41 m on the 6MWD test. The 90-day readmission rate for patients reduced to 5% from 14% after receiving cardiac rehabilitation.

CONCLUSION

Home-based cardiac rehabilitation offered the most improved results in functional capacity, QOL, and a reduced the rate of readmission within 90 days.

Impaired chronotropic response to physical activities in heart failure patients

Background

While exercise-based cardiac rehabilitation has a beneficial effect on heart failure hospitalization and mortality, it is limited by the presence of chronotropic incompetence (CI) in some patients. This study explored the feasibility of using wearable devices to assess impaired chronotropic response in heart failure patients.

Methods

Forty patients with heart failure (left ventricular ejection fraction, LVEF: 44.6 ± 5.8; age: 54.4 ± 11.7) received ECG Holter and accelerometer to monitor heart rate (HR) and physical activities during symptom-limited treadmill exercise testing, 6-min hall walk (6MHW), and 24-h daily living. CI was defined as maximal HR during peak exercise testing failing to reach 70% of age-predicted maximal HR (APMHR, 220 – age). The correlation between HR and physical activities in Holter-accelerometer recording was analyzed.

Results

Of 40 enrolled patients, 26 were able to perform treadmill exercise testing. Based on exercise test reports, 13 (50%) of 26 patients did not achieve at least 70% of APMHR (CI patients). CI patients achieved a lower % APMHR (62.0 ± 6.3%) than non-CI patients who achieved 72.0 ± 1.2% of APMHR (P < 0.0001). When Holter-accelerometer recording was used to assess chronotropic response, the percent APMHR achieved during 6MHW and physical activities was significantly lower in CI patients than in non-CI patients. CI patients had a significantly shorter 6MHW distance and less physical activity intensity than non-CI patients.

Conclusion

The study found impaired chronotropic response in 50% of heart failure patients who took treadmill exercise testing. The wearable Holter-accelerometer recording could help to identify impaired chronotropic response to physical activities in heart failure patients.

Trial registration

ClinicalTrials.gov ID NCT02358603. Registered 16 May 2014.

Physical activity is associated with reduced fatigue in adults living with HIV/AIDS

AIMS

The aim of this study was to describe the relationships among home-based physical activity, fatigue, sleep, gender and quality of life in people living with HIV/AIDS BACKGROUND: Fatigue is a common and distressing symptom among people living with HIV/AIDS. Few interventions exist that effectively reduce fatigue in this population. Physical activity has shown promise to reduce fatigue in other populations, but its impact on fatigue in HIV/AIDS has not yet been explored.

DESIGN

This study was conducted using a prospective, descriptive cohort design.

METHODS

Overall, 90 adults living with HIV/AIDS completed cross-sectional measures. Home-based physical activity was measured using a 7-day self-report diary. Fatigue was measured using the self-reported HIV-Related Fatigue Scale. Sleep was assessed using wrist actigraphy and quality of life was assessed using the HIV-Associated Quality of Life Scale. Data were collected from December 2012-April 2013 and analysed using correlations and multiple linear regression.

RESULTS

The number of minutes of home-based physical activity was significantly associated with reduced fatigue among people living with HIV/AIDS. In addition, increased fatigue was associated with decreased quality of life. No associations were found among fatigue, sleep or gender.

CONCLUSIONS

Our study demonstrates that physical activity in the home setting is an effective strategy to reduce fatigue among people living with HIV/AIDS. Future work developing and testing interventions to improve home-based physical activity in this population is needed.

Alternatives to Aerobic Exercise Prescription in Patients with Chronic Heart Failure

Background

Exercise is essential for patients with heart failure as it leads to a reduction in morbidity and mortality as well as improved functional capacity and oxygen uptake (⩒O₂). However, the need for an experienced physiologist and the cost of the exam may render the cardiopulmonary exercise test (CPET) unfeasible. Thus, the six-minute walk test (6MWT) and step test (ST) may be alternatives for exercise prescription.

Objective

The aim was to correlate heart rate (HR) during the 6MWT and ST with HR at the anaerobic threshold (HR_AT) and peak HR (HR_P) obtained on the CPET.

Methods

Eighty-three patients (58 ± 11 years) with heart failure (NYHA class II) were included and all subjects had optimized medication for at least 3 months. Evaluations involved CPET (⩒O₂, HR_AT, HR_P), 6MWT (HR_6MWT) and ST (HR_ST).

Results

The participants exhibited severe ventricular dysfunction (ejection fraction: 31 ± 7%) and low peak ⩒O2 (15.2 ± 3.1 mL.kg_-1.min_-1). HR_P (113 ± 19 bpm) was higher than HR_AT (92 ± 14 bpm; p < 0.05) and HR_6MWT (94 ± 13 bpm; p < 0.05). No significant difference was found between HR_P and HR_ST. Moreover, a strong correlation was found between HR_AT and HR_6MWT (r = 0.81; p < 0.0001), and between HR_P and HR_ST (r = 0.89; p < 0.0001).

Conclusion

These findings suggest that, in the absence of CPET, exercise prescription can be performed by use of 6MWT and ST, based on HR_6MWT and HR_ST

Cardiac Rehabilitation in Patients With Heart Failure: New Perspectives in Exercise Training

Exercise training is recommended to patients with chronic heart failure (CHF) and reduced ejection fraction at a class 1 evidence level. Currently the 'dose' of exercise (dose being both volume and intensity) still remains uncertain and the best form of aerobic exercise training has not been defined. Guidelines commonly use heart rate (HR) as a target factor for both moderate continuous and interval training exercises. However, exercise training guided by HR can be limited in CHF patients due to chronotropic incompetence and beta-blocker treatment. In our study, we systematically addressed the above issues by applying a training method that takes into account both the volume and intensity of exercise on an individual basis. This method is referred to as individual TRaining IMPulses (TRIMPi). In this review, we summarise a series of investigations that used TRIMPi and different exercise forms to quantify the optimum training load in CHF patients. This review also highlights the way TRIMPi and the individual exercise dose affects cardiorespiratory, metabolic and autonomic cardiac adaptations.

Validation of rate of perceived exertion-based exercise training in patients with heart failure: insights from autonomic nervous system adaptations

BACKGROUND

Exercise prescription in cardiac patients is based on heart rate (HR) response to exercise. How to prescribe long-term exercise training outside medically-supervised settings also considering changes in individual physical capacity over time is unknown. In this study we hypothesized that in patients with chronic heart failure (CHF) the session-rate of perceived exertion (RPE), a subjective-based training methodology, provides autonomic and functional capacity changes superimposable to those observed with HR-based Training Impulses (TRIMPi) method.

METHODS

Twenty patients with stable CHF were randomized to either aerobic continuous training (ACT) or aerobic interval training (AIT) for 12 weeks. For each TRIMPi-guided exercise session, the session-RPE was recorded. By this method, internal training load (TL) is quantified by multiplying the RPE of the whole training session, using the Borg CR10-scale, by its duration. Heart rate variability (HRV), and baroreflex sensitivity (BRS) were assessed at baseline and at 3 weeks intervals.

RESULTS

Significant correlations were found between TRIMPi and individual session-RPE, for both ACT and AIT (r=0.63 to 0.81), (P<0.05). The same occurred when ACT and AIT groups were pooled together (r=0.72; P<0.01). R-R interval, HRV and BRS were significantly and very highly correlated with weekly RPE-session (r(2) ranged from 0.77 to 0.97; P<0.001). A significant relationship between session-RPE and performance at the 6MWT was also found.

CONCLUSIONS

Session-RPE is an easy-to-use, inexpensive and valid method for exercise prescription and health maintenance, consistent with objective physiological indices of training, that could be used for long-term physical activity in patients with CHF.

The Benefits of Rehabilitation for Palliative Care Patients

Palliative care requires an interdisciplinary team approach to provide the best care for patients with life-threatening illnesses. Like palliative medicine, rehabilitation also uses an interdisciplinary approach to treating patients with chronic illnesses. This review article focuses on rehabilitation interventions that can be beneficial in patients with late stage illnesses. Rehabilitation may be useful in improving the quality of life by palliating function, mobility, activities of daily living, pain relief, endurance, and the psyche of a patient while helping to maintain as much independence as possible, leading to a decrease in burden on caregivers and family. Rehabilitative services are underutilized in the palliative care setting, and more research is needed to address how patients may benefit as they approach the end of their lives.

Hypoxic exercise training improves cardiac/muscular hemodynamics and is associated with modulated circulating progenitor cells in sedentary men

BACKGROUND

Circulating progenitor cells (CPCs) improve cardiovascular function and organ perfusion by enhancing the capacities of endothelial repair and neovasculogenesis. This study investigates whether exercise regimens with/without hypoxia affect cardiac and muscular hemodynamics by modulating CPCs and angiogenic factors.

METHODS

Forty sedentary males were randomly divided into hypoxic (HT, n=20) and normoxic (NT, n=20) training groups. The subjects were trained on a bicycle ergometer at 60%VO(2max) under 15% (HT) or 21% (NT) O2 conditions for 30 min daily, five days weekly for five weeks.

RESULTS

After the five-week interventions, the HT group exhibited a larger improvement in aerobic capacity than the NT group. Furthermore, the HT regimen (i) enhanced cardiac output (Q(H)) and perfusion (Q(M))/oxygenation of vastus lateralis during exercise; (ii) increased levels of CD34(+)/KDR(+)/CD117(+), CD34(+)/KDR(+)/CD133(+), and CD34(+)/KDR(+)/CD31(+) cells in blood; (iii) promoted the proliferative capacity of these CPC subsets, and (iv) elevated plasma nitrite/nitrate, stromal cell-derived factor-1 (SDF-1), matrix metalloproteinase-9 (MMP-9), and vascular endothelial growth factor-A (VEGF-A) concentrations. Despite the lack of changes in Q(H) and the number or proliferative capacity of CD34(+)/KDR(+)/CD117(+) or CD34(+)/KDR(+)/CD31(+) cells, the NT regimen elevated both Q(M) and plasma nitrite/nitrate levels and suppressed the shedding of endothelial cells (CD34(-)/KDR(+)/phosphatidylserine(+) cells).

CONCLUSIONS

The HT regimen improves cardiac and muscular hemodynamic adaptations, possibly by promoting the mobilization/function of CPCs and the production of angiogenic factors.

Programming exercise intensity in patients on beta-blocker treatment: the importance of choosing an appropriate method

AIM

To verify the usefulness of current recommended level of target exercise heart rate (HR) and of different HR-based methods for calculating target HR in patients with and without beta-blocker treatment.

METHODS

We studied 53 patients not treated with beta-blocker and 159 patients on beta-blocker treatment. All patients underwent a maximal exercise test with gas analysis, and first ventilatory threshold (VT1 or aerobic threshold), second ventilatory threshold (VT2 or anaerobic threshold), time of exercise, maximum load, metabolic parameters, HR at rest (HRrest), HRpeak, HR at VT1 (HRVT1) and at VT2 (HRVT2), and 75, 80, and 85% of HRmax (HR75%, HR80%, HR85%) were calculated. Exercise HR was also determined using the Karvonen formula, applying 60, 70, and 80% of the heart rate reserve (HRR) (HRKarv0.6, HRKarv0.7, and HRKarv0.8).

RESULTS

This study included 102 patients on a beta-blocker and 39 not treated with negative cronotropic effect drugs. Maximum load, metabolic parameters, HRrest, HRpeak, HRVT1, and HRVT2 were significantly lower in patients on beta-blocker treatment. The proportion of patients with a HR75%, HR80%, HR85%, ​​HRKarv0.6, HRKarv0.7, and HRKarv0.8 <VT1 and >VT2 was very high and depended on whether patients were on beta-blocker treatment.

CONCLUSIONS

Prescribed exercise intensity should be within VT1 and VT2, so that the efficacy and safety is guaranteed. If determining VT1 and VT2 is not possible, HR-based methods can be used, but with caution. In fact, there will be always a proportion of patients training below VT1 or above VT2. On the other hand, recommendations for patients on a beta-blocker should be different from patients not receiving a beta-blocker. Patients not treated with a beta-blocker should exercise at HRKarv0.7 or at HR85%. In patients on a beta-blocker, we recommend preferentially a target HR of HRKarv0.6 or HR80%.

Exercise training in chronic heart failure

The syndrome of heart failure (HF) is a growing epidemic that causes a significant socio-economic burden. Despite considerable progress in the management of patients with HF, mortality and morbidity remain a major healthcare concern and frequent hospital admissions jeopardize daily life and social activities. Exercise training is an important adjunct nonpharmacological treatment modality for patients with HF that has proven positive effects on mortality, morbidity, exercise capacity and quality of life. Different training modalities are available to target the problems with which HF patients are faced. It is essential to tailor the prescribed exercise regimen, so that both efficiency and safety are guaranteed. Electrical implanted devices and mechanical support should not exclude patients from exercise training; however, particular precautions and a specialized approach are advised. At least 50% of patients with HF, older than 65 years of age, present with HF with preserved ejection fraction (HFPEF). Although the study populations included in studies evaluating the effect of exercise training in this population are small, the results are promising and seem to support the idea that exercise training is beneficial for HFPEF patients. Both the short- and especially long-term adherence to exercise training remain a major challenge that can only be tackled by a multidisciplinary approach. Efforts should be directed towards closing the gap between recommendations and the actual implementation of training programmes.

Minute ventilation and heart rate relationship for estimation of the ventilatory compensation point at high altitude: a pilot study

BACKGROUND

The ventilatory compensation point (VCP) is an exercise threshold which has been used in the design of training programs in sports medicine and rehabilitation. We recently demonstrated that changes in the slope of the minute ventilation to heart rate relationship (ΔV˙E/ΔHR) can be utilized for estimation of the VCP during incremental exercise at sea level (SL). We hypothesized that in hypoxic conditions, such as high altitude (HA), VCP can be also reliably estimated by ΔV˙E/ΔHR.

METHODS

At SL and on immediate ascent to HA (5,050 m), six healthy subjects (42 ± 14 SD years) performed a maximal incremental exercise test on a cycle ergometer; O2 uptake (V˙O2), CO2 output (V˙CO2), V˙E, and HR were measured breath-by-breath. The ΔV˙E/ΔHR method for VCP estimation was compared to the standard method using the ventilatory equivalent for CO2 (V˙E/V˙CO2) and end-tidal PCO2 (PETCO2). The ΔV˙E/ΔHR slope values below (S1) and above (S2) VCP were computed by linear regression analysis.

RESULTS

A significant difference between S1 and S2 was observed, at SL and HA, for both the ΔV˙E/ΔHR and V˙E/V˙CO2 methods for VCP estimation. A good agreement between the two methods (ΔV˙E/ΔHR vs. V˙E/V˙CO2) was found for both environmental conditions; the mean difference ± 2 SD of V˙O2 at VCP (VCP-V˙O2) was -22 ± 112 ml/min at SL and 39 ± 81 ml/min at HA. The VCP-V˙O2 was significantly lower at HA compared to SL; in addition, S1 and S2 mean values were significantly higher at HA compared to SL.

CONCLUSION

At HA, VCP may be reliably estimated by the ΔV˙E/ΔHR method.

Effect of outpatient exercise training programmes in patients with chronic heart failure: a systematic review

BACKGROUND

Advantages of outpatient exercise training are reduced waiting lists, better compliance, reduced time investment by the patient with reduced travel expenses, and less dependence on other people to participate. Therefore, this systematic review studies the effects of outpatient exercise training programmes compared with usual care on exercise capacity, exercise performance, quality of life, and safety in patients with chronic heart failure.

DESIGN

Systematic review with meta-analysis.

METHODS

Randomized controlled trials concerning patients with chronic heart failure, with a left ventricular ejection fraction ≤40%, were included. A meta-analysis was performed.

RESULTS

Twenty-two studies were included. VO(2)max, 6-min walking test, and quality of life showed significant differences in favour of the intervention group of 1.85 ml/kg/min, 47.9 m, and 6.9 points, respectively. In none of the studies, a significant relationship was found between exercise training and adverse events.

CONCLUSION

This meta-analysis illustrates the efficacy and safety of outpatient training programmes for patients with chronic heart failure.

Aerobic exercise prescription in patients with chronic heart failure: a review in the beta-blocker era

Aerobic exercise training is a well-established nonpharmacological tool in patients with clinically stable chronic heart failure. In recent years, β-blocker therapy has become a primary pharmacologic intervention in patients with chronic heart failure. Despite the undeniable improvements in patients, the β-blocker era has aroused uncertainties about aerobic exercise intensity prescription. It is well known that aerobic exercise prescription is performed by a percentage of the patient's heart rate reserve and the use of β-blockers could interfere in this method. For this reason, the aim of this review is to provide an update about aerobic exercise prescription in patients with chronic heart failure who are using β-blockers.

[Risk reduction in cardiovascular diseases by physical activity]

A sedentary lifestyle or physical inactivity is recognized as an important risk factor for cardiovascular diseases. Regular physical activity improves muscular function, cardiac function, and metabolic syndrome-related disorders. Leisure time physical activity reduces all-cause mortality by 22-34% and cardiovascular mortality by 27-35%. These data have been shown in many prospective cohort studies and published in four large meta-analyses with more than 800,000 participants (evidence IA). The risk reduction is somewhat more pronounced in the elderly and in women (IB). In addition to reduced mortality, physical activity also improves cardiopulmonary function and quality of life (IB). This also holds true for coronary artery disease, cardiac failure, and arterial hypertension with high-grade evidence (IA). Furthermore, evidence has been shown a risk reduction in stroke, development of cognitive dysfunction, and intermittent claudication. Training recommendations for physical activity have reached high-grade evidence (IA). Therefore, regular physical activity is one of the most important components of a healthy lifestyle. All physicians should ask their patients at all clinic and office visits about physical activity and recommend activity for prevention and therapy.

Endurance exercise intensity determination in the rehabilitation of coronary artery disease patients: a critical re-appraisal of current evidence

In the care of coronary artery disease (CAD) patients, the benefits of exercise therapy are generally established. Even though the selected endurance exercise intensity might affect medical safety, therapy adherence and effectiveness in the rehabilitation of CAD patients in how to determine endurance exercise intensity properly remains difficult. The aim of this review is to describe the available methods for endurance exercise intensity determination in the rehabilitation of CAD patients, accompanied with their (dis)advantages, validity and reproducibility. In general, endurance exercise intensity can objectively be determined in CAD patients by calculating a fraction of maximal exercise tolerance and/or determining ventilatory threshold after execution of a cardiopulmonary exercise test with ergospirometry. This can be translated to a corresponding training heart rate (HR) or workload. In the absence of ergospirometry equipment, target exercise HR can be calculated directly by different ways (fraction of maximal HR and/or Karvonen formula), and/or anaerobic threshold can be determined. However, the use of HR for determining exercise intensity during training sessions seems complicated, because many factors/conditions affect the HR. In this regard, proper standardization of the exercise sessions, as well as exercise testing, might be required to improve the accuracy of exercise intensity determination. Alternatively, subjective methods for the determination of endurance exercise intensity in CAD patients, such as the Borg ratings of perceived exertion and the talk test, have been developed. However, these methods lack proper validity and reliability to determine endurance exercise intensity in CAD patients. In conclusion, a practical and systematic approach for the determination of endurance exercise intensity in CAD patients is presented in this article.

Aerobic interval training improves oxygen uptake efficiency by enhancing cerebral and muscular hemodynamics in patients with heart failure

BACKGROUND

Abnormal ventilatory/hemodynamic responses to exercise contribute to functional impairment in patients with heart failure (HF). This study investigates how interval and continuous exercise regimens influence functional capacity by modulating ventilatory efficiency and hemodynamic function in HF patients.

METHODS

Forty-five HF patients were randomized to perform either aerobic interval training (AIT; 3-minute intervals at 40% and 80% VO(2peak)) or moderate continuous training (MCT; sustained 60% VO()for 30 min/day, 3 days/week for 12 weeks, or to a control group that received general healthcare (GHC). A noninvasive bio-reactance device was adopted to measure cardiac hemodynamics, whereas a near-infrared spectroscopy was employed to assess perfusion/O2 extraction in frontal cerebral lobe (∆[THb]FC/∆[HHb]FC) and vastus lateralis (∆[THb]VL/∆[HHb]VL), respectively.

RESULTS

Following the 12-week intervention, the AIT group exhibited higher oxygen uptake efficiency slope (OUES) and lower VE-VCO2 slope than the MCT and GHC groups. Furthermore, AIT, but not MCT, boosted cardiac output (CO) and increased ∆[THb]FC, ∆[THb]VL, and ∆[HHb]VL during exercise. In multivariate analyses, CO was the dominant predictor of VO(2peak). ∆[THb]FC and ∆[THb]VL, which modulated the correlation between CO and OUES, were significantly correlated with OUES. Simultaneously, ∆[THb]VL was the only factor significantly associated with VE-VCO2 slope. Additionally, AIT reduced plasma brain natriuretic peptide, myeloperoxidase, and interleukin-6 levels and increased the Short Form-36 physical/mental component scores and decreased the Minnesota Living with Heart Failure questionnaire score.

CONCLUSIONS

AIT effectively improves oxygen uptake efficiency by enhancing cerebral/muscular hemodynamics and suppresses oxidative stress/inflammation associated with cardiac dysfunction, and also promotes generic/disease-specific qualities of life in patients with HF.

Special needs to prescribe exercise intensity for scientific studies

There is clear evidence regarding the health benefits of physical activity. These benefits follow a dose-response relationship with a particular respect to exercise intensity. Guidelines for exercise testing and prescription have been established to provide optimal standards for exercise training. A wide range of intensities is used to prescribe exercise, but this approach is limited. Usually percentages of maximal oxygen uptake (VO₂) or heart rate (HR) are applied to set exercise training intensity but this approach yields substantially variable metabolic and cardiocirculatory responses. Heterogeneous acute responses and training effects are explained by the nonuniform heart rate performance curve during incremental exercise which significantly alters the calculations of %HR_max and %HRR target HR data. Similar limitations hold true for using %VO_2max and %VO₂R. The solution of these shortcomings is to strictly apply objective submaximal markers such as thresholds or turn points and to tailor exercise training within defined regions.