Effects of exercise rehabilitation program on heart rate recovery in patients with chronic heart failure

High-Intensity Interval Training Programs Versus Moderate-Intensity Continuous Training for Individuals With Heart Failure: A Systematic Review and Meta-analysis

OBJECTIVE

To explore the effect sizes of different high-intensity interval training (HIIT) protocols on cardiorespiratory parameters when compared with moderate-intensity continuous training (MICT) in different heart failure (HF) subtypes.

DATA SOURCES

Electronic databases were searched from their inception date until January 23, 2023.

STUDY SELECTION

Randomized controlled trials (RCTs) were included if they compared HIIT with MICT in patients with HF. The primary outcome was peak oxygen consumption (Vo2peak). Two reviewers independently evaluated 99 initially identified studies, resulting in the selection of 15 RCTs that met the eligibility criteria.

DATA EXTRACTION

Data were extracted independently by 2 observers using a data extraction form drafted based on the CONSORT statement and the Template for Intervention Description and Replication; the methodological quality of the studies was analyzed individually based on the Tool for the Assessment of Study Quality in Exercise scale.

DATA SYNTHESIS

Fifteen RCTs with 553 patients with HF were included in the systematic review. The included studies had moderate to good overall methodological quality. The results showed that HIIT was generally more effective than MICT at improving Vo2peak in patients with HF (n=541, 15 RCTs; MD: 1.49 mL/kg/min; I2=66%; P<.001). However, the effect size varied depending on the HF subtype and HIIT protocol used. For patients with HF with reduced ejection fraction (HFrEF), the long-interval (high-intensity interval lasting ≥4 min) and high-volume HIIT (high-intensity efforts in total ≥15 min) showed the largest benefits over the MICT (n=261, 6 RCTs; MD: 2.11 mL/kg/min; P<.001); followed by the short-interval (≤1 min) and high-volume HIIT (≥15 min; n=71, 3 RCTs; MD: 0.91 mL/kg/min; P=.12), and the short-interval and low-volume HIIT showed the least superiority over MICT (n=68, 3 RCTs; MD: 0.54 mL/kg/min; P=.05). For patients with HF with perceived ejection fraction, there was a modest beneficial effect from HIIT over MICT (n=141, 3 RCTs; MD: 0.55 mL/kg/min; P=.32).

CONCLUSIONS

The long-interval and high-volume HIIT protocol may produce greater benefits than MICT for improving cardiopulmonary fitness in patients with HFrEF. Further research is needed to determine the optimal HIIT protocol for different HF subtypes and to provide definitive recommendations for clinical practice.

Non-Pharmacological Interventions in Patients With Heart Failure With Reduced Ejection Fraction: A Systematic Review and Network Meta-analysis

OBJECTIVE

To determine the effectiveness of non-pharmacologic interventions and the additional benefits of their combination in patients with heart failure with reduced ejection fraction (HFrEF).

DATA SOURCES

We searched PubMed, Embase, and the Cochrane Clinical Trials Register from the date of database inception to April 22, 2023.

STUDY SELECTION

Randomized controlled trials involving non-pharmacologic interventions conducted in patients with HFrEF were included.

DATA EXTRACTION

Data were extracted by 2 independent reviewers based on a pre-tested data extraction form. The quality of evidence was assessed using the Cochrane Risk of Bias tool and the Grading of Recommendations Assessment, Development, and Evaluation method.

DATA SYNTHESIS

A total of 82 eligible studies (4574 participants) were included. We performed a random-effects model within a Bayesian framework to calculate weighted mean differences (WMDs) and 95% credibility intervals. High or moderate certainty evidence indicated that high-intensity aerobic interval training (HIAIT) was best on improving 6-minute walk distance (6MWD; 68.55 m [36.41, 100.47]) and left ventricular ejection fraction (6.28% [3.88, 8.77]), while high-intensity aerobic continuous training (HIACT) is best on improving peak oxygen consumption (Peak VO2; 3.48 mL/kg•min [2.84, 4.12]), quality of life (QOL; -17.26 [-29.99, -7.80]), resting heart rate (-8.20 bpm [-13.32, -3.05]), and N-terminal pro-B-type natriuretic peptide (-600.96 pg/mL [-902.93, -404.52]). Moderate certainty evidence supported the effectiveness of inspiratory muscle training to improve peak oxygen consumption and functional electrical stimulation to improve QOL. Moderate-intensity aerobic continuous training (MIACT) plus moderate-intensity resistance training (MIRT) had additional benefits in Peak VO2, 6MWD, and QOL. This review did not provide a comprehensive evaluation of adverse events.

CONCLUSIONS

Both HIAIT and HIACT are the most effective single non-pharmacologic interventions for HFrEF. MIACT plus MIRT had additional benefits in improving peak oxygen consumption, 6MWD, and QOL.

Abnormal Heart Rate Recovery and Chronotropic Incompetence With Exercise in Patients With Interstitial Lung Disease With and Without Pulmonary Hypertension

Introduction Chronotropic incompetence (CI) and heart rate (HR) recovery at one minute post-exercise (HRR1) have been proposed as indicators of autonomic imbalance. We retrospectively studied the presence of CI and HRR1 attained on cardiopulmonary exercise testing (CPET) in patients with interstitial lung disease (ILD) and those with interstitial lung disease with pulmonary hypertension (ILD-PHTN). Methods A total of 32 patients (21 had ILD alone; 11 had ILD-PHTN) underwent CPET performed per American Thoracic Society protocol on a manually-braked bicycle. HRR1 was defined as the difference between peak HR and HR after one minute post-exercise. The utilization of HR reserve recovery at peak exercise was expressed as Chronotropic Response Index (CRI) and was calculated as (peak HR-resting HR)/(220-age-resting HR). CI was defined by failure to reach 85% of the age-predicted maximum heart rate (APMHR = 200-Age) and CRI<0.80 (80%). Results VO2max was lower in patients with ILD-PHTN compared to ILD alone (14.15± 5.00 vs. 18.11± 4.48, p<0.05). Mean CRI (0.468± 0.179 versus 0.691± 0.210, p<0.05) and HRR1 (10± 7 versus 18± 9, p<0.05) were lower in patients with ILD-PHTN compared to ILD alone. Twenty out of a total of 32 patients (62.5%) met the criteria for CI. In the ILD group, 10 out of 21 patients (47.62%) and in the ILD-PHTN group 10 of 11 patients (90.90%) had CI. Conclusion Chronotropic Incompetence and abnormal heart rate recovery at one minute post-exercise are notable in patients with ILD and are more severe in patients with ILD-PHTN. These findings may contribute to our understanding of dyspnea due to these conditions.

A 2-week high-intensity interval training intervention improves ejaculation control among men with premature ejaculation

BACKGROUND

Premature ejaculation (PE), which leads to substantial distress in men and their partners, is a common male sexual dysfunction worldwide. However, there is still a lack of effective treatments without side effects.

OBJECTIVES

We investigated the effect of high-intensity interval training (HIIT) on PE symptoms.

MATERIALS AND METHODS

We recruited 92 Chinese men aged 18-36 to complete the experiment. There were 22 (13 in the control group; 9 in the HIIT group) men diagnosed with PE and 70 (41 in the control group; 29 in the HIIT group) men with normal ejaculatory function. In the HIIT group, participants completed HIIT exercises every morning for 14 days. Participants also completed surveys inquiring about demographic information, erectile function, PE symptoms, body image (including sexual body image), physical activity, and sexual desire. The heart rate was measured before and after each HIIT. In the control group, participants were instructed not to do HIIT, but other procedures were the same as in the HIIT group.

RESULTS

Results indicated that the HIIT intervention alleviated PE symptoms in men with PE. In addition, in the HIIT group, men with PE who had a higher heart-rate increase during the HIIT intervention reported the greatest overall decrements in PE symptoms. In men with normal ejaculatory function, HIIT did not decrease PE symptoms. In addition, increments in the heart rate during the intervention were associated with more pronounced PE symptoms post-intervention in this group. Analyses of secondary outcome measures suggested that the HIIT intervention improved general and sexual body image satisfaction of men with PE compared to before the intervention.

DISCUSSION AND CONCLUSION

In summary, HIIT intervention may reduce PE symptoms in men with PE. The heart-rate increase during the intervention may be a key factor influencing the effect of the HIIT intervention on PE symptoms.

Effects of high intensity interval training versus moderate intensity continuous training on exercise capacity and quality of life in patients with heart failure: A systematic review and meta-analysis

INTRODUCTION AND AIMS

High intensity interval training (HIIT) is considered as an alternative exercise modality to moderate intensity continuous training (MICT) for heart failure (HF) patients. Yet a growing number of trials demonstrated inconsistent findings about the effectiveness of HIIT versus MICT until SMARTEX study and OptimEx-Clin study have made a consistent negative conclusion that HIIT was not superior to MICT. The aim of this study was to conduct a meta-analysis involving a subgroup analysis of total exercise time (TET) and disease categories of HF to investigate if TET could affect the superiority of HIIT when compared with MICT.

METHODS AND RESULTS

An electronic literature search of Pubmed, Embase, Cochrane Central Register of Controlled Trials and ClinicalTrials.gov was performed for this review. 16 studies of 661 patients were finally pooled into quantitative synthesis. The weighted mean difference (WMD) and standard mean difference (SMD) with 95% confidence interval (CI) were calculated for quantitative synthesis of outcomes. HIIT was superior to MICT in improving peak oxygen consumption (Peak VO2) (WMD: 1.68 ml · kg-1 · min-1 95% CI: 0.81 to 2.55 n = 661). The subgroup analysis of TET showed that HIIT was superior to MICT in improving Peak VO2 in "short time" subgroup (WMD: 1.61 ml · kg-1 · min-1 95% CI: 0.45 to 2.77 n = 166) and in "medium time" subgroup (WMD: 1.74 ml · kg-1 · min-1 95% CI: 0.53 to 2.95 n = 420), and that there was no significant difference between HIIT and MICT in improving Peak VO2 in "long time" subgroup (WMD: 0.62 ml · kg-1 · min-1 95% CI: -1.34 to 2.58 n = 75).

CONCLUSIONS

The superiority of HIIT to MICT in improving Peak VO2 arose in a short to medium length of TET whereas it was effaced by an increment of TET. This "paradox" of TET on HIIT versus MICT might be due to the increasing poor adherence to target exercise intensity over time.

TRIAL REGISTRATION

PROSPERO registration number: CRD42022375076.

Association between postoperative delirium and heart rate variability in the intensive care unit and readmissions and mortality in elderly patients with cardiovascular surgery

This study aimed to investigate the relationship between heart rate variability (HRV), a parameter of the autonomic nervous system activity (ANSA), and postoperative delirium and postoperative events. This retrospective cohort study included elderly patients aged 65 years or older who were admitted to the intensive care unit (ICU) after cardiovascular surgery. ANSA was measured using HRV parameters for 1 h at daytime and 1 h at night-time before ICU discharge. The primary endpoint was the effect of HRV parameters and delirium on mortality and readmission rates within 1 year after discharge, and the secondary endpoint was the association between HRV parameters and delirium. Cox proportional hazards models were used to examine the association between HRV parameters and postoperative events by adjusting for delirium and pre and postoperative information. A total of 71 patients, 39 without delirium and 32 with delirium, met the inclusion criteria. The incidence of death and readmission within 1 year was significantly higher in the delirium group and in the group with higher daytime HF (high frequency power) and r-MSSD (square root of the squared mean of the difference of successive NN intervals), parameters of the parasympathetic nervous system activity (PNSA), than that in other groups. Furthermore, the delirium group had significantly higher HF and r-MSSD than the nondelirium group. Even after adjusting for confounding factors in the multivariate analysis, a trend of higher daytime HF and r-MSSD was observed, indicating a significant effect on the occurrence of combined events within 1 year of discharge. ICU delirium has been associated with higher daytime HF and r-MSSD, parameters of PNSA. ICU delirium was a prognostic factor, and increased daytime PNSA may worsen the prognosis of elderly patients after cardiovascular surgery.

Effect of Menstrual Cycle Phase on the Recovery Process of High-Intensity Interval Exercise-A Cross-Sectional Observational Study

Although the study of the menstrual cycle influence on endurance exercise has recently increased, there is a lack of literature studying its influence on females' cardiorespiratory recovery. Thus, the aim of the present work was to assess menstrual cycle influence on post-exercise recovery following a high intensity interval exercise in trained females. Thirteen eumenorrheic endurance-trained females performed an interval running protocol in three menstrual cycle phases: early follicular phase (EFP), late follicular phase (LFP), and mid-luteal phase (MLP). The protocol consisted of 8 × 3-min bouts at 85% of their maximal aerobic speed (vVO2peak) with a 90-s rest between bouts and a final 5-min active recovery at 30% vVO2peak. All variables were averaged every 15 s, obtaining 19 moments during recovery (time factor). To analyze the effects of the menstrual cycle on the final active cardiorespiratory recovery, an ANOVA for repeated measures was performed. ANOVA showed an effect on menstrual cycle phase on ventilation (EFP: 1.27 ± 0.35; LFP: 1.19 ± 0.36; MLP: 1.27 ± 0.37), breathing frequency (EFP: 35.14 ± 7.14; LFP: 36.32 ± 7.11; MLP: 37.62 ± 7.23), and carbon dioxide production (EFP: 1120.46 ± 137.62; LFP: 1079.50 ± 129.57; MLP: 1148.78 ± 107.91). Regarding the interaction results (phase x time), ventilation is higher at many of the recovery times during the MLP, with less frequent differences between EFP and LFP (F = 1.586; p = 0.019), while breathing reserve is lower at many of the recovery times during MLP, with less time differences between EFP and LFP (F = 1.643; p = 0.013). It seems that the menstrual cycle affects post-exercise recovery specially during the MLP, rising ventilation and lowering breathing reserve, giving rise to an impaired ventilatory efficiency.

Exercise Mode in Heart Failure: A Systematic Review and Meta-Analysis

BACKGROUND

Optimising exercise prescription in heart failure (HF) with a preserved (HFpEF) or reduced (HFrEF) ejection fraction is clinically important. As such, the aim of this meta-analysis was to compare traditional moderate intensity training (MIT) against combined aerobic and resistance training (CT) and high-intensity interval training (HIIT) for improving aerobic capacity (VO₂), as well as other clinically relevant parameters.

METHODS

A comprehensive systematic search was performed to identify randomised controlled trials published between 1990 and May 2021. Research trials reporting the effects of MIT against CT or HIIT on peak VO₂ in HFpEF or HFrEF were considered. Left-ventricular ejection fraction (LVEF) and various markers of diastolic function were also analysed.

RESULTS

Seventeen studies were included in the final analysis, 4 of which compared MIT against CT and 13 compared MIT against HIIT. There were no significant differences between MIT and CT for peak VO₂ (weighted mean difference [WMD]: 0.521 ml min^-1 kg^-1, [95% CI] =  - 0.7 to 1.8, P_fixed = 0.412) or LVEF (WMD: - 1.129%, [95% CI] =  - 3.8 to 1.5, P_fixed = 0.408). However, HIIT was significantly more effective than MIT at improving peak VO₂ (WMD: 1.62 ml min^-1 kg^-1, [95% CI] = 0.6-2.6, P_random = 0.002) and LVEF (WMD: 3.24%, [95% CI] = 1.7-4.8, P_random < 0.001) in HF patients. When dichotomized by HF phenotype, HIIT remained significantly more effective than MIT in all analyses except for peak VO₂ in HFpEF.

CONCLUSIONS

HIIT is significantly more effective than MIT for improving peak VO₂ and LVEF in HF patients. With the exception of peak VO₂ in HFpEF, these findings remain consistent in both phenotypes. Separately, there is no difference in peak VO₂ and LVEF change following MIT or CT, suggesting that the addition of resistance exercise does not inhibit aerobic adaptations in HF.

Exercise Training in Heart failure with Preserved and Reduced Ejection Fraction: A Systematic Review and Meta-Analysis

Background

While exercise training (ET) is an established tool in heart failure (HF), no research to date has analysed the efficacy of ET in both preserved (HFpEF) and reduced (HFrEF) ejection fraction phenotypes across the same clinically important parameters.

Methods

A comprehensive systematic search was performed to identify trials published between 1990 and May 2021. Controlled trials of adults reporting pre- and post-ET peak VO2, 6-min walk distance (6MWD), Minnesota Living with Heart Failure Questionnaire (MLHFQ), Kansas City Cardiomyopathy Questionnaire (KCCQ) and left ventricular ejection fraction (LVEF) were considered. Parameters of cardiac diastolic function, brain natriuretic peptides (BNP)/N-terminal prohormone of BNP (NTproBNP) and follow-up hospitalisation and mortality data were also analysed.

Results

Ninety-three studies (11 HFpEF and 82 HFrEF) were included in the final analysis, with a pooled sample size of 11,081 participants. HFpEF analysis demonstrated significant improvements in peak VO2 (weighted mean difference: 2.333 ml·min^-1·kg^-1, P_fixed < 0.001), 6MWD (WMD: 35.396 m, P_fixed < 0.001), MLHFQ (WMD: − 10.932, P_random < 0.001), KCCQ (WMD: 3.709, P_fixed = 0.037) and E/e′ (WMD: − 1.709, [95% CI] = − 2.91–0.51, P_random = 0.005). HFrEF analysis demonstrated significant improvements in peak VO2 (WMD: 3.050 ml·min^-1·kg^-1, P_random < 0.001), 6MWD (WMD: 37.299 m, P_random < 0.001), MLHFQ (WMD: − 10.932, P_random < 0.001), LVEF (WMD: 2.677%, P_random = 0.002) and BNP/NTproBNP (SMD: − 1.349, P_random < 0.001). Outcome analysis was only performed in HFrEF, which found no significant changes in hospitalisation, all-cause mortality or composite end-points.

Conclusion

ET significantly improves exercise capacity and quality of life in both HFpEF and HFrEF patients. In HFpEF patients, ET significantly improved an important index of diastolic function, with significant improvements in LVEF and NTproBNP/BNP seen in HFrEF patients only. Such benefits did not translate into significantly reduced hospitalisation or mortality after short-term follow-up.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00464-5.

Acute Cardiorespiratory Responses to Different Exercise Modalities in Chronic Heart Failure Patients-A Pilot Study

The purpose of this study was to compare the acute cardiorespiratory responses and time spent above different %VO_2peak intensities between three "iso-work" protocols: (a) a high intensity interval training protocol (HIIT), (b) a higher intensity continuous protocol (CON₇₀) and (c) a lower intensity continuous protocol (CON₅₀) in patients with chronic heart failure (CHF). Ten male CHF patients (aged 55.1 ± 16.2 years) performed in separate days a single session of a HIIT protocol consisted of 4 sets × 4 min cycling at 80% VO_2peak with 3 min of recovery at 50% VO_2peak, a CON₇₀ protocol corresponding to 70% VO_2peak and a CON₅₀ protocol corresponding to 50% VO_2peak. Cardiopulmonary data were collected by an online gas analysis system. The HIIT and CON₇₀ elicited higher cardiorespiratory responses compared to CON₅₀ with no differences between them (p > 0.05). In HIIT and CON₇₀, patients exercised longer at >80% and >90% VO_2peak. The completion rate was 100% for the three protocols. Not any adverse events were observed in either protocol. Both HIIT and CON₇₀ elicited a stronger physiological stimulus and required shorter time than CON₅₀. Both HIIT and CON₇₀ also induced comparable hemodynamic responses and ventilatory demand.

Integrating patients with chronic respiratory disease and heart failure into a combined breathlessness rehabilitation programme: a service redesign and pilot evaluation

INTRODUCTION

The successful integration of patients with chronic heart failure (CHF) into a traditional pulmonary rehabilitation (PR) programme has previously been reported. Our aim was to reconfigure both our cardiac rehabilitation (CR) and PR services to enable us to deliver a symptom-based programme-breathlessness rehabilitation (BR), for patients with a primary symptom of breathlessness irrespective of the index diagnosis, or comorbid disease.

METHODS

After a service redesign process, patients attended a two times per week, group-based, tailored exercise and education programme for 6 weeks, delivered by CR and PR staff. The classes included both aerobic and resistance exercises and an overarching generic education programme alongside disease-specific components. Home programmes were reviewed at each session to facilitate progress and influence changes in exercise behaviour beyond the supervised programme. Generic clinical outcome measures were performed pre and post BR.Staff focus groups were conducted to identify barriers and facilitators and explore staff perceptions.

RESULTS

272 patients (n=193 chronic respiratory disease (CRD) and n=79 CHF) were assessed and enrolled into BR (153 men, mean (SD) age 68.8 (12.7) years, body mass index 28.8 (7.3), Medical Research Council 3 (IQR 2-4), New York Heart Association 2 (IQR 2-3)). 164 patients completed the programme. Statistically significant improvements were seen in both exercise capacity (incremental shuttle walking test: mean change 47.4 m; endurance shuttle walking test: mean change 310.7 s) and quadriceps strength (quadriceps maximal voluntary contraction: mean change 3.7 kg) (p≤0.0001) alongside a statistically significant reduction in dyspnoea (chronic respiratory questionnaire/chronic heart questionnaire - self reported - dyspnoea: mean change 0.4) and anxiety and depression scores (Hospital Anxiety and Depression Scale (HADS) - anxiety: -1.6; HADS - depression: -1.3) (p≤0.0001).Qualitative staff focus groups identified three subthemes: collaboration and integration, service quality and future challenges.

DISCUSSION

Overall the service redesign indicates the feasibility for staff and individuals with CRD and CHF to integrate into a breathlessness programme. Early data suggests clinical effectiveness. Given the significance of comorbid disease it is an approach that warrants further consideration.

The impact of cardiomotor rehabilitation on endothelial function in elderly patients with chronic heart failure

Background

To explore the effects of cardiac exercise rehabilitation on peripheral blood endothelial progenitor cells (EPC) in elderly patients with chronic heart failure.

Methods

80 elderly patients with chronic heart failure were selected from March 2017 to March 2019 and randomly divided into two groups (N = 40). The control group was treated routinely and walked freely for 30–60 min every day. The patients in the exercise rehabilitation group developed a cardiac exercise rehabilitation plan. Then, cardiac function and peripheral blood B-natriuretic peptide (BNP) levels in the two groups were compared. The cell viability, proliferation, apoptosis, and invasion ability of EPCs were detected. The levels of the PI3K/AKT pathway and eNOS and VEGF were compared.

Results

There were no significant differences in all indexes between the two groups before treatment (P > 0.05), and both improved significantly after treatment (P < 0.05). After treatment, LVEF and LVFS in the exercise rehabilitation group were significantly higher than those in the control group (P < 0.05), and LVEDD and LVESD were significantly lower than those in the control group (P < 0.05). The BNP level in the exercise rehabilitation group was significantly lower than that in the control group (P < 0.05). The cell viability, proliferation, invasion ability of EPC, and the levels of PI3K, AKT, eNOS, and VEGF mRNA and protein in the exercise rehabilitation group were significantly higher than those in the control group. Apoptosis rate was significantly lower than those in the control group (P < 0.05).

Conclusions

Visceral exercise rehabilitation can improve cardiac ejection and myocardial function in elderly patients with chronic heart failure, and can promote the vitality, proliferation, and invasion of peripheral blood EPC, and promote the expression of eNOS and VEGF by upregulating the PI3K/AKT pathway to promote angiogenesis and endothelial function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02327-5.

The Effects of Interval Training and Continuous Training on Cardiopulmonary Fitness and Exercise Tolerance of Patients with Heart Failure-A Systematic Review and Meta-Analysis

PURPOSE

To investigate the effects of interval training (IT) as compared with continuous training (CT) on cardiorespiratory fitness and exercise tolerance of patients with heart failure (HF), with the aim to provide reasonable exercise prescriptions for patients with HF.

METHODS

Through searching electronic databases, randomized controlled studies were collected. The included studies were evaluated for methodological quality using the Cochrane risk of bias assessment tool, and statistical analyses were carried out using Review Manager 5.3 and Stata MP 15.1 software.

RESULTS

A total of seventeen randomized controlled trials (i.e., studies) with 617 patients were included. The meta-analysis showed that IT can improve a patient's peak oxygen uptake (VO2peak) (MD = 2.08, 95% CI 1.16 to 2.99, p < 0.00001), left ventricular ejection fraction (LVEF) (MD =1.32, 95% CI 0.60 to 2.03, p = 0.0003), and 6-minute walk distance (6MWD) (MD = 25.67, 95% CI 12.87 to 38.47, p < 0.0001) as compared with CT. However, for respiratory exchange ratio (RER) (MD = 0.00, 95% CI -0.02 to 0.03, p = 0.81), CO2 ventilation equivalent slope (VE/VCO2 slope) (SMD = 0.04, 95% CI -0.23 to 0.31, p = 0.75), and resting heart rate (HRrest) (MD = 0.15, 95% CI -3.00 to 3.29, p = 0.93) there were no statistical significance.

CONCLUSIONS

The evidence shows that IT is better than CT for improving the cardiorespiratory fitness and exercise tolerance of patients with HF. Moreover, an intensity of 60-80% peak heart rate of IT is the optimal choice for patients. It is hoped that, in the future, more well-designed studies would further expand the meta-analysis results.

Effects of high-intensity interval training in a three-week cardiovascular rehabilitation: a randomized controlled trial

Objective:

The aim of this study was to assess the benefit of using high-intensity interval training for cardiovascular patients undergoing outpatient rehabilitation in a standard short-term (three-week) program in Germany.

Design:

This is a randomized controlled trial (RCT).

Setting:

This study was conducted at Cardiowell (Wuppertal, Germany), an outpatient rehabilitation center.

Intervention:

Patients underwent the typical three-week German outpatient rehabilitation program using either moderate continuous training (i.e. the standard training program) or high-intensity interval training.

Main measures:

A total of 50 patients of an outpatient rehabilitation center were randomized into two groups. The control group underwent the standard rehabilitation protocol that applied moderate continuous training, and the intervention group trained according to a high-intensity interval protocol. Patients trained on a bicycle ergometer. Peak power output, oxygen uptake parameters, heart frequencies, and blood pressure were compared at the beginning and at the end of the rehabilitation program.

Results:

After three weeks, the intervention group had improved to a significantly greater extent in maximal performance parameters than the control group: the peak power output (20.9 (±14.1) W; control 8.8 (±10.4) W), maximum oxygen uptake (0.33 (±0.33) L/min; control 0.05 (±0.29) L/min)), relative maximum oxygen uptake (3.4 (±4.2) mL/kg/min; control 0.9 (±3.1) mL/kg/min), and O2 pulse (1.8 (±2.2) mL/heart beat; control 0.35 (±1.7) mL/heart beat).

Conclusion:

The implementation of high-intensity interval training during a typical three-week German cardiac rehabilitation has the power to increase the outcome for the patients.

High-Intensity Interval Training for Patients With Cardiovascular Disease-Is It Safe? A Systematic Review

Background

Cardiac rehabilitation (CR) for patients with cardiovascular disease has traditionally involved low‐ to moderate‐intensity continuous aerobic exercise training (MICT). There is growing and robust evidence that high‐intensity interval training (HIIT) shows similar or greater efficacy compared with MICT across a range of cardiovascular and metabolic measures, in both healthy populations and populations with a chronic illness. However, there is understandable concern about the safety aspects of applying HIIT in CR settings. This systematic review analyzed safety data drawn from recent proof‐of‐concept studies of HIIT during CR among patients with cardiovascular disease.

Methods and Results

We included trials comparing HIIT with either MICT or usual care in patients with coronary artery disease or heart failure participating in tertiary care services, such as phase 2 (outpatient) CR. Adverse events occurring during or up to 4 hours after an exercise training session were collated. There were 23 studies included, which analyzed 1117 participants (HIIT=547; MICT=570). One major cardiovascular adverse event occurred in relation to an HIIT session, equating to 1 major cardiovascular event per 17 083 training sessions (11 333 training hours). One minor cardiovascular adverse events and 3 noncardiovascular adverse events (primarily musculoskeletal complaints) were also reported for HIIT. Two noncardiovascular events were reported in relation to MICT.

Conclusions

HIIT has shown a relatively low rate of major adverse cardiovascular events for patients with coronary artery disease or heart failure when applied within CR settings.

Association between heart rate recovery after exercise and renal function in patients referred for treadmill exercise test

Introduction

Heart rate recovery (HRR) is a marker of parasympathetic activity recovery after exercise, and it is associated with cardiovascular mortality and total mortality. Impaired renal function is also associated with cardiac mortality. The aim of this study was to investigate the association between HRR after exercise and renal function in patients referred for a treadmill exercise test.

Patients and methods

This cross-sectional study was conducted at a regional hospital in southern Taiwan. Patients who completed a symptom-limited treadmill exercise test from January 2015 to February 2018 were recruited. Before the treadmill exercise test, patients were asked to complete a questionnaire on the past disease history and lifestyle factors. Serum creatinine measurement within two years prior to or after the date of the treadmill exercise test of the patients was also obtained from the medical records for these patients. Estimated glomerular filtration rate (eGFR) was calculated. Simple and multiple linear regression analyses were performed to investigate the association between one-minute HRR and eGFR.

Results

A total of 2,825 patients completed the treadmill exercise test, and serum creatinine measurement was identified from medical records for 2,153 patients (76.2%). Multiple linear regression analysis revealed that a lower eGFR was significantly associated with lower one-minute HRR (P< 0.001), adjusting for other significant independent factors, including age, waist circumference, type 2 diabetes mellitus, and smoking.

Conclusions

In this cross-sectional observational study, a lower eGFR was significantly and independently associated with decreased one-minute HRR, suggesting that parasympathetic activity recovery after exercise could be impaired by a decrease in renal function.

High-intensity interval training for health benefits and care of cardiac diseases - The key to an efficient exercise protocol

Aerobic capacity, which is expressed as peak oxygen consumption (VO_2peak), is well-known to be an independent predictor of all-cause mortality and cardiovascular prognosis. This is true even for people with various coronary risk factors and cardiovascular diseases. Although exercise training is the best method to improve VO_2peak, the guidelines of most academic societies recommend 150 or 75 min of moderate- or vigorous- intensity physical activities, respectively, every week to gain health benefits. For general health and primary and secondary cardiovascular prevention, high-intensity interval training (HIIT) has been recognized as an efficient exercise protocol with short exercise sessions. Given the availability of the numerous HIIT protocols, which can be classified into aerobic HIIT and anaerobic HIIT [usually called sprint interval training (SIT)], professionals in health-related fields, including primary physicians and cardiologists, may find it confusing when trying to select an appropriate protocol for their patients. This review describes the classifications of aerobic HIIT and SIT, and their differences in terms of effects, target subjects, adaptability, working mechanisms, and safety. Understanding the HIIT protocols and adopting the correct type for each subject would lead to better improvements in VO_2peak with higher adherence and less risk.

Aerobic Interval vs. Continuous Training in Patients with Coronary Artery Disease or Heart Failure: An Updated Systematic Review and Meta-Analysis with a Focus on Secondary Outcomes

BACKGROUND

In a previous meta-analysis including nine trials comparing aerobic interval training with aerobic continuous training in patients with coronary artery disease, we found a significant difference in peak oxygen uptake favoring aerobic interval training.

OBJECTIVE

The objective of this study was to (1) update the original meta-analysis focussing on peak oxygen uptake and (2) evaluate the effect on secondary outcomes.

METHODS

We conducted a systematic review with a meta-analysis by searching PubMed and SPORTDiscus databases up to March 2017. We included randomized trials comparing aerobic interval training and aerobic continuous training in patients with coronary artery disease or chronic heart failure. The primary outcome was change in peak oxygen uptake. Secondary outcomes included cardiorespiratory parameters, cardiovascular risk factors, cardiac and vascular function, and quality of life.

RESULTS

Twenty-four papers were identified (n = 1080; mean age 60.7 ± 10.7 years). Aerobic interval training resulted in a higher increase in peak oxygen uptake compared with aerobic continuous training in all patients (1.40 mL/kg/min; p < 0.001), and in the subgroups of patients with coronary artery disease (1.25 mL/kg/min; p = 0.001) and patients with chronic heart failure with reduced ejection fraction (1.46 mL/kg/min; p = 0.03). Moreover, a larger increase of the first ventilatory threshold and peak heart rate was observed after aerobic interval training in all patients. Other cardiorespiratory parameters, cardiovascular risk factors, and quality of life were equally affected.

CONCLUSION

This meta-analysis adds further evidence to the clinically significant larger increase in peak oxygen uptake following aerobic interval training vs. aerobic continuous training in patients with coronary artery disease and chronic heart failure. More well-designed randomized controlled trials are needed to establish the safety of aerobic interval training and the sustainability of the training response over longer periods.

Exercise for Preventing Hospitalization and Readmission in Adults With Congestive Heart Failure

We critically appraised all available evidence regarding exercise interventions for improving patient survival and reducing hospital admissions in adults with chronic heart failure (HF). We searched 4 databases up to April 2018 and graded the quality of evidence according to the Grading of Recommendations Assessment, Development and Evaluation working group approach. We reviewed 7 meta-analyses and the publications of 48 randomized controlled trials (RCTs). In HF with reduced ejection fraction, low-quality evidence suggests that exercise prevents all-cause hospitalizations [Relative risk (RR), 0.77; 95% confidence interval (CI), 0.63 to 0.93; 1328 patients in 15 RCTs] and hospitalizations due to HF (RR, 0.57; 95% CI, 0.37 to 0.88; 1073 patients in 13 RCTs) and improves quality of life (standardized mean difference, -0.37; 95% CI, -0.60 to -0.14; 1270 patients in 25 RCTs) but has no effect on mortality. In HF with preserved ejection fraction, low-quality evidence suggests that exercise improves peak oxygen uptake (mean difference, 2.36; 95% CI, 1.16 to 3.57; 171 patients in 3 RCTs) and quality of life (mean difference, -4.65; 95% CI, -8.46 to -0.83; 203 patients in 4 RCTs). In patients after heart transplantation, low-quality evidence suggests that exercise improves peak oxygen uptake (standardized mean difference, 0.68; 95% CI, 0.43 to 0.93; 284 patients in 9 RCTs) but does not improve quality of life. In order to reduce hospitalization and improve quality of life for adults with HF and reduced ejection fraction, clinicians should recommend exercise interventions. For adults with HF and preserved ejection fraction and in those undergoing heart transplantation, clinicians may recommend exercise interventions in order to improve peak oxygen uptake.

Exercise training improves characteristics of exercise oscillatory ventilation in chronic heart failure

Background Exercise oscillatory ventilation in chronic heart failure has been suggested as a factor related to adverse cardiac events, aggravated prognosis and higher mortality. Exercise training is well known to affect exercise capacity and mechanisms of pathophysiology beneficially in chronic heart failure. Little is known, however, about the exercise training effects on characteristics of exercise oscillatory ventilation in chronic heart failure patients. Design and methods Twenty (out of 38) stable chronic heart failure patients exhibited exercise oscillatory ventilation (age 54 ± 11 years, peak oxygen uptake 15.0 ± 5.0 ml/kg per minute). Patients attended 36 sessions of high intensity interval exercise. All patients underwent cardiopulmonary exercise testing before and after the programme. Assessment of exercise oscillatory ventilation was based on the amplitude of cyclic fluctuations in breathing during rest and exercise. All values are mean ± SD. Results Exercise training reduced ( P < 0.05) the percentage of exercise oscillatory ventilation duration (79.0 ± 13.0 to 50.0 ± 25.0%), while average amplitude (5.2 ± 2.0 to 4.9 ± 1.6 L/minute) and length (44.0 ± 10.9 to 41.0 ± 6.7 seconds) did not change ( P > 0.05). Exercise oscillatory ventilation patients also increased exercise capacity ( P < 0.05). Conclusions A rehabilitation programme based on high intensity interval training improved exercise oscillatory ventilation observed in chronic heart failure patients, as well as cardiopulmonary efficiency and functional capacity.

The Correlation of Decreased Heart Rate Recovery and Chronotropic Incompetence with Exercise Capacity in Idiopathic Pulmonary Arterial Hypertension Patients

We show by this study that a decrease in HRR1 in IPAH patients is associated with severe limitation of exercise capacity. HRR1 < 16 beats and CI just after completion of a CPET could be an indicator of poor prognosis.

Effects of High-Intensity Interval Training on Aerobic Capacity in Cardiac Patients: A Systematic Review with Meta-Analysis

Purpose. The aim of this study was to compare the effects of high-intensity interval training (INTERVAL) and moderate-intensity continuous training (CONTINUOUS) on aerobic capacity in cardiac patients. Methods. A meta-analysis identified by searching the PubMed, Cochrane Library, EMBASE, and Web of Science databases from inception through December 2016 compared the effects of INTERVAL and CONTINUOUS among cardiac patients. Results. Twenty-one studies involving 736 participants with cardiac diseases were included. Compared with CONTINUOUS, INTERVAL was associated with greater improvement in peak VO₂ (mean difference 1.76 mL/kg/min, 95% confidence interval 1.06 to 2.46 mL/kg/min, p < 0.001) and VO₂ at AT (mean difference 0.90 mL/kg/min, 95% confidence interval 0.0 to 1.72 mL/kg/min, p = 0.03). No significant difference between the INTERVAL and CONTINUOUS groups was observed in terms of peak heart rate, peak minute ventilation, VE/VCO₂ slope and respiratory exchange ratio, body mass, systolic or diastolic blood pressure, triglyceride or low- or high-density lipoprotein cholesterol level, flow-mediated dilation, or left ventricular ejection fraction. Conclusions. This study showed that INTERVAL improves aerobic capacity more effectively than does CONTINUOUS in cardiac patients. Further studies with larger samples are needed to confirm our observations.

Improvement in aerobic capacity during cardiac rehabilitation in coronary artery disease patients: Is there a role for autonomic adaptations?

Background It has been previously shown in patients with heart failure that exercise-based rehabilitation programmes may improve functional capacity and autonomic response. The aim of this study was to investigate this issue further by evaluating whether an association exists between autonomic adaptations and improvements of aerobic capacity in a general population of coronary artery disease patients undergoing cardiac rehabilitation. Methods Ninety consecutive patients (age 60 ± 11 years) attended a rehabilitation programme of moderate continuous training (25 ± 8 sessions, 2-3 sessions/week). Functional capacity expressed as oxygen uptake (peak VO₂) and autonomic function expressed as chronotropic response and heart rate recovery were evaluated by cardiopulmonary exercise tests before and after the rehabilitation programme. According to the expected mean increase in functional capacity, coronary artery disease patients were divided into two groups: those who improved peak VO₂ by more than 2.6 ml/kg/min (R group) and those who did not (NR group). Effects of the rehabilitation programme were compared in R and NR groups. Results The number and intensity of exercise sessions did not differ between R ( N = 39) and NR ( N = 51) groups. However, only R patients improved chronotropic response (R: from 45.1 ± 16.9% to 72.7 ± 34.1%, P < 0.01; NR: from 49.3 ± 18.6% to 48.2 ± 36.5%, P = NS) and heart rate recovery (R: from 16.9 ± 7.0 bpm to 21.0 ± 8.7 bpm, P < 0.01; NR: from 15.2 ± 9.9 bpm to 15.8 ± 8.5 bpm, P = NS). After training both chronotropic response and heart rate recovery were significantly higher in R than NR patients. Conclusions The improvement in aerobic capacity of coronary artery disease patients following exercise-based cardiac rehabilitation programmes is associated with positive adaptations of autonomic function.

Effects of High-Intensity Interval Training versus Continuous Training on Physical Fitness, Cardiovascular Function and Quality of Life in Heart Failure Patients

Introduction

Physical fitness is an important prognostic factor in heart failure (HF). To improve fitness, different types of exercise have been explored, with recent focus on high-intensity interval training (HIT). We comprehensively compared effects of HIT versus continuous training (CT) in HF patients NYHA II-III on physical fitness, cardiovascular function and structure, and quality of life, and hypothesize that HIT leads to superior improvements compared to CT.

Methods

Twenty HF patients (male:female 19:1, 64±8 yrs, ejection fraction 38±6%) were allocated to 12-weeks of HIT (10*1-minute at 90% maximal workload—alternated by 2.5 minutes at 30% maximal workload) or CT (30 minutes at 60–75% of maximal workload). Before and after intervention, we examined physical fitness (incremental cycling test), cardiac function and structure (echocardiography), vascular function and structure (ultrasound) and quality of life (SF-36, Minnesota living with HF questionnaire (MLHFQ)).

Results

Training improved maximal workload, peak oxygen uptake (VO_2peak) related to the predicted VO_2peak, oxygen uptake at the anaerobic threshold, and maximal oxygen pulse (all P<0.05), whilst no differences were present between HIT and CT (N.S.). We found no major changes in resting cardiovascular function and structure. SF-36 physical function score improved after training (P<0.05), whilst SF-36 total score and MLHFQ did not change after training (N.S.).

Conclusion

Training induced significant improvements in parameters of physical fitness, although no evidence for superiority of HIT over CT was demonstrated. No major effect of training was found on cardiovascular structure and function or quality of life in HF patients NYHA II-III.

Trial Registration

Nederlands Trial Register NTR3671

Possible neurocognitive benefits of exercise in persons with heart failure

More than 6 million Americans have heart failure (HF) and more than 500,000 are diagnosed each year. In addition to its many adverse medical consequences, HF is also a significant risk factor for neurological disorders like Alzheimer's disease and associated with cognitive impairment long prior to the onset of these conditions. Converging bodies of literature suggest cognitive dysfunction in HF may be at least partially modifiable. One key mechanism for cognitive improvement is improved cerebral blood flow, which may be possible with exercise in patients with HF. This brief review provides a model for the likely neurocognitive benefits of exercise in HF and encourages further work in this area.

Effects of Exercise Training on Autonomic Function in Chronic Heart Failure: Systematic Review

Objectives. Cardiac autonomic imbalance accompanies the progression of chronic heart failure (CHF). It is unclear whether exercise training could modulate autonomic control in CHF. This study aimed to review systematically the effects of exercise training on heart rate recovery (HRR) and heart rate variability (HRV) in patients with CHF. Methods. Literatures were systematically searched in electronic databases and relevant references. Only published randomized controlled trials (RCTs) focusing on exercise training for CHF were eligible for inclusion. Outcome measurements included HRR and HRV parameters. Results. Eight RCTs were eligible for inclusion and provided data on 280 participants (186 men). The participants were 52–70 years of age with New York Heart Association functional class II-III of CHF. Each study examined either aerobic or resistance exercise. Two trials addressed outcome of HRR and six HRV among these studies. Two RCTs showed that moderate aerobic exercise could improve HRR at 2 minutes after exercise training in CHF. Five of six RCTs demonstrated positive effects of exercise training on HRV which revealed the increments in high frequency (HF) and decrements in LF (low frequency)/HF ratio after training. Conclusion. Participation in an exercise training program has positive effects on cardiac autonomic balance in patients with CHF.

Chronotropic Incompetence and Dynamic Postexercise Autonomic Dysfunction Are Associated with the Presence and Severity of Erectile Dysfunction

BACKGROUND

Exercise stress testing (EST) is crucial to determine cardiovascular (CV) risk in men with erectile dysfunction (ED). Low exercise workload, a slower rate of recovery following exercise, and an impaired capacity to increase heart rate (HR) during exercise testing (chronotropic incompetence) are independent predictors of adverse CV outcomes. Aim of this study was to investigate the association between ED and EST parameters.

METHODS

A total of 180 ED patients and 50 men without ED underwent maximal EST. Exercise parameters including exercise capacity (metabolic equivalents, METS), peak exercise time, HR at six METS, peak exercise, HR recovery (HRR) at 1 and 2 minutes and chronotropic index (CI) were evaluated in all individuals. Endothelial function was evaluated with flow-mediated dilatation (FMD) of the brachial artery.

RESULTS

ED patients had lower peak exercise time and thus lower calculated exercise capacity (P < 0.001) and reduced CI (P < 0.01) compared to men without ED. There was a significant association of ED severity with duration of exercise, peak workload, HRR 2 minutes after exercise, and CI (all P < 0.05). There also was a positive relation of HRR and CI with FMD (all P < 0.05).

CONCLUSIONS

This study shows interrelationships between exercise capacity, HRR, CI, and ED. Abnormal HRR and CI are associated with systemic endothelial dysfunction. These findings imply pathophysiological links and may have important implications for the estimation of cardiovascular risk in ED patients.

Aerobic exercise effect on prognostic markers for systolic heart failure patients: a systematic review and meta-analysis

From previous systematic reviews and meta-analyses, there is consensus about the positive effect of exercise training on exercise capacity for systolic heart failure (HF); however, the effect on actual prognostic markers such as NTproBNP and minute ventilation/carbon dioxide production (VE/VCO2) slope has not been evaluated. The primary aim of the proposed study is to determine the effect of aerobic exercise training (AEX) on the VE/VCO2 slope and NTproBNP. The following databases (up to February 30, 2013) were searched with no language limitations: CENTRAL (The Cochrane Library 2013, issue 2), MEDLINE (from January 1966), EMBASE (from January 1980), and Physiotherapy Evidence Database (PEDro) (from January 1929). We screened reference lists of articles and also conducted an extensive hand search of the literature. Randomized controlled trials of exercise-based interventions with 2-month follow-up or longer compared to usual medical care or placebo were included. The study population comprised adults aged between 18 and 65 years, with evidence of chronic systolic heart failure (LVEF < 45 % and baseline NTproBNP > 300 pg/ml). Two review authors independently extracted data on study design, participants, interventions, and outcomes. We assessed the risk of bias using PEDro scale. We calculated mean differences (MD) or standardized mean differences between intervention and control groups for outcomes with sufficient data; for other outcomes, we described findings from individual studies. Eight studies involving a total of 408 participants met the inclusion criteria across the NTproBNP (5 studies with 191 patients) and VE/VCO2 slope (4 studies with 217 patients). Aerobic exercise significantly improved NTproBNP by a MD of -817.75 [95 % confidence interval (CI) -929.31 to -706.19]. Mean differences across VE/VCO2 slope were -6.55 (95 % CI -7.24 to -5.87). Those patients' characteristics and exercise were similar (frequency = 3-5 times/week; duration = 20-50 min/day; intensity = 60-80 % of VO2 peak) on the included studies. Moreover, the risk of bias across all studies was homogeneous (PEDro scale = 7-8 points). However, based on the statistical analysis, the heterogeneity among the studies was still high, which is related to the variable characteristics of the studies. Aerobic exercise may be effective at improving NTproBNP and the VE/VCO2 slope in systolic HF patients, but these effects are limited to a specific HF population meeting specific inclusion criterion in a limited number of studies. Future randomized controlled studies including diastolic and HF overleap with pulmonary diseases are needed to better understand the exact influence of AEX.

Aerobic interval training vs. moderate continuous training in coronary artery disease patients: a systematic review and meta-analysis

BACKGROUND

Exercise training improves exercise capacity (peakVO2), which is closely related to long-term survival in cardiac patients. However, it remains unclear which type and intensity of exercise is most effective for improving exercise tolerance and body weight. Individual studies suggest that aerobic interval training (AIT) might increase peakVO2 more in this population.

OBJECTIVE

We conducted a meta-analysis to summarize the effects of AIT compared with moderate continuous training (MCT) on peakVO2, submaximal exercise capacity, and body weight in patients with coronary artery disease (CAD) with preserved and/or reduced left ventricular ejection fraction (LVEF).

DATA SOURCES AND STUDY SELECTION

A systematic search was conducted and we included randomized trials comparing AIT and MCT in CAD patients lasting at least 4 weeks, reporting peakVO2 results, and published in a peer-reviewed journal up to May 2013. The primary outcome measure was peakVO2. Secondary outcomes were submaximal exercise capacity parameters and body weight.

SYNTHESIS METHODS

Random- and fixed-effects models were used and data were reported as weighted means and 95% confidence intervals (CIs).

RESULTS

Nine study groups were included, involving 206 patients (100 AIT, 106 MCT). Overall, AIT resulted in a significantly larger increase in peakVO2 [+1.60 mL/kg/min (95% CI 0.18-3.02; p = 0.03)] compared with MCT. MCT seemed to be more effective in reducing body weight (-0.78 kg; 95% CI -0.01 to 1.58; p = 0.05).

LIMITATIONS

The small number of studies might have affected the power to reach significance for the secondary outcomes.

CONCLUSION

In CAD patients with preserved and/or reduced LVEF, AIT is superior to MCT for improving peakVO2, while MCT seems to be more effective in reducing body weight. However, large, well-designed, randomized controlled trials are warranted to confirm these findings.

The effects of baseline heart rate recovery normality and exercise training protocol on heart rate recovery in patients with heart failure

Objective:

It is unclear which exercise training protocol yields superior heart rate recovery (HRR) improvement in heart failure (HF) patients. Whether baseline HRR normality plays a role in the improvement is unknown. We hypothesized that an exercise training protocol and baseline HRR normality would be factors in altering HRR in HF patients.

Methods:

In this prospective, randomized, controlled and 3 group parallel study, 41 stable HF patients were randomly assigned to 3-times-weekly training sessions for 12 weeks, consisting of i) 30 minutes of interval training (IT) (n=17, 63.7±8.8 years old) versus ii) 30 minutes of continuous training (CT) (n=13, 59.6±6.8 years old) versus iii) no training (CON) (n=11, 60.6±9.9 years old). Each patient had cardiopulmonary exercise testing before and after the training program. Maximum heart rates attained during the test and heart rates at 1 and 2 min (HRR1 and HRR2) during the recovery phase were recorded. Paired samples t-test or Wilcoxon signed-rank test was used for comparisons before and after training. One-way ANOVA or Kruskal-Wallis variance analysis was used for comparisons among groups.

Results:

HRR1 was unchanged after training. HRR2 improved in the IT group after training, and post-training HRR2 values were significantly faster in the IT group than in controls. Both HRR1 and HRR2 was significantly faster, irrespective of exercise protocol in patients with abnormal baseline values after training.

Conclusion:

HRR1 did not improve after training. HRR2 improved only in the IT group. Both HRRs in patients with abnormal baseline values improved after both exercise protocols. IT might be superior to CT in improving HRR2. Baseline HRR might play a role in its response to exercise.

Greater physical activity is associated with better cognitive function in heart failure

OBJECTIVE

Nearly 6 million Americans have heart failure (HF), up to 80% of which exhibit cognitive deficits on testing. Physical inactivity is common in HF, yet little is known about the possible contribution of physical inactivity to cognitive dysfunction in this population.

METHOD

Older adults with HF (N = 93; Mage = 68.5 years, 33.7% women) completed neuropsychological testing, as well as cardiac and physical activity assessment as part of a larger protocol. HF severity was measured via impedance cardiography. Physical activity was assessed via an Actigraph accelerometer and operationalized using daily step count and time engaged in moderate-vigorous activity (minutes/day).

RESULTS

Linear regression analyses controlling for sex, high blood pressure, diabetes, depressive symptomatology, and HF severity showed that greater physical activity (both step count and minutes spent in moderate-vigorous activity) was associated with better executive function/attention, processing speed, and scores on a screening measure of cognition.

CONCLUSIONS

These findings indicate that physical activity is an independent predictor of cognitive function in persons with HF. Future work is needed to clarify the mechanisms by which physical activity benefits cognitive function in HF and determine whether interventions to promote physical activity can attenuate cognitive decline over time.

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.

High-intensity aerobic interval exercise in chronic heart failure

Aerobic exercise training is strongly recommended in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF) to improve symptoms and quality of life. Moderate-intensity aerobic continuous exercise (MICE) is the best established training modality in HF patients. For about a decade, however, another training modality, high-intensity aerobic interval exercise (HIIE), has aroused considerable interest in cardiac rehabilitation. Originally used by athletes, HIIE consists of repeated bouts of high-intensity exercise interspersed with recovery periods. The rationale for its use is to increase exercise time spent in high-intensity zones, thereby increasing the training stimulus. Several studies have demonstrated that HIIE is more effective than MICE, notably for improving exercise capacity in patients with HF. The aim of the present review is to describe the general principles of HIIE prescription, the acute physiological effects, the longer-term training effects, and finally the future perspectives of HIIE in patients with HF.

Should high-intensity-aerobic interval training become the clinical standard in heart failure?

Aerobic exercise training in the heart failure (HF) population is supported by an extensive body of literature. The clinically accepted model for exercise prescription is currently moderate-intensity-aerobic continuous training (MI-ACT). Documented benefits from the literature include improvements in various aspects of physiologic function, aerobic exercise capacity and quality of life while the impact on morbidity and mortality is promising but requires further investigation. Recently, however, a body of evidence has begun to emerge demonstrating high-intensity-aerobic interval training (HI-AIT) can be performed safely with impressive improvements in physiology, functional capacity and quality of life. These initial findings have led some to question the long-standing clinical approach to aerobic exercise training in patients with HF (i.e., MI-ACT), implying it should perhaps be replaced with a HI-AIT model. This is a potentially controversial paradigm shift given the potential increase in adverse event risk associated with exercising at higher intensities, particularly in the HF population where the likelihood of an untoward episode is already at a heightened state relative to the apparently healthy population. The present review therefore addresses key issues related to HI-AIT in the HF population and makes recommendations for future research and current clinical practice.

Heart rate recovery and heart rate variability are unchanged in patients with coronary artery disease following 12 weeks of high-intensity interval and moderate-intensity endurance exercise training

Decreased heart rate variability and attenuated heart rate recovery following exercise are associated with an increased risk of mortality in cardiac patients. This study investigated the effects of 12 weeks of moderate-intensity endurance exercise (END) and a novel low-volume high-intensity interval exercise protocol (HIT) on measures of heart rate recovery and heart rate variability in patients with coronary artery disease (CAD). Fourteen males with CAD participated in 12 weeks of END or HIT training, each consisting of 2 supervised exercise sessions per week. END consisted of 30-50 min of continuous cycling at 60% peak power output (PPO). HIT involved ten 1-min intervals at 88% PPO separated by 1-min intervals at 10% PPO. Heart rate recovery at 1 min and 2 min was measured before and after training (pre- and post-training, respectively) using a submaximal exercise bout. Resting time and spectral and nonlinear domain measures of heart rate variability were calculated. Following 12 weeks of END and HIT, there was no change in heart rate recovery at 1 min (END, 40 ± 12 beats·min(-1) vs. 37 ± 19 beats·min(-1); HIT, 31 ± 8 beats·min(-1) vs. 35 ± 8 beats·min(-1); p ≥ 0.05 for pre- vs. post-training) or 2 min (END, 44 ± 18 beats·min(-1) vs. 43 ± 19 beats·min(-1); HIT, 42 ± 10 beats·min(-1) vs. 50 ± 6 beats·min(-1); p ≥ 0.05 for pre- vs. post-training). All heart rate variability indices were unchanged following END and HIT training. In conclusion, neither END nor HIT exercise programs elicited training-induced improvements in cardiac autonomic function in patients with CAD. The absence of improvements with training may be attributed to the optimal medical management and normative pretraining state of our sample.

Circulating endothelial and progenitor cells: Evidence from acute and long-term exercise effects

Circulating bone-marrow-derived cells, named endothelial progenitor cells (EPCs), are capable of maintaining, generating, and replacing terminally differentiated cells within their own specific tissue as a consequence of physiological cell turnover or tissue damage due to injury. Endothelium maintenance and restoration of normal endothelial cell function is guaranteed by a complex physiological procedure in which EPCs play a significant role. Decreased number of peripheral blood EPCs has been associated with endothelial dysfunction and high cardiovascular risk. In this review, we initially report current knowledge with regard to the role of EPCs in healthy subjects and the clinical value of EPCs in different disease populations such as arterial hypertension, obstructive sleep-apnea syndrome, obesity, diabetes mellitus, peripheral arterial disease, coronary artery disease, pulmonary hypertension, and heart failure. Recent studies have introduced the novel concept that physical activity, either performed as a single exercise session or performed as part of an exercise training program, results in a significant increase of circulating EPCs. In the second part of this review we provide preliminary evidence from recent studies investigating the effects of acute and long-term exercise in healthy subjects and athletes as well as in disease populations.

Sleep apnea and cognitive function in heart failure

Background. Prior research indicates that heart failure (HF) patients exhibit significant cognitive deficits on neuropsychological testing. Sleep apnea is associated with both HF and reduced cognitive function, but the combined impact of these conditions on cognitive function is unknown. Methods. In the current study, 172 older adults with a dual diagnosis of HF and sleep apnea or HF alone completed a battery of cognitive tests measuring attention, executive functioning, and memory. Results. Relative to patients with HF alone, persons with both HF and sleep apnea performed worse on measures of attention after adjusting for demographic and medical variables. Conclusions. The current findings suggest that HF patients with comorbid sleep apnea may be at greater risk for cognitive impairment relative to HF patient without such history. Further work is needed to clarify mechanisms for these findings and to determine whether the interactive effects on cognitive function lead to poorer patient outcomes.

Individual patient meta-analysis of exercise training effects on systemic brain natriuretic peptide expression in heart failure

BACKGROUND

Brain natriuretic peptide (BNP) predicts exercise performance and exercise training may modulate BNP and its N-terminal portion (NT-pro-BNP), we therefore conducted an individual patient analysis of exercise training effects on BNP and NT-pro-BNP.

AIMS

To use an individual patient meta-analysis to relate changes in BNP, NT-pro-BNP, and peak VO(2); to link these changes to volume parameters of exercise training programmes (intensity etc.); and to identify patient characteristics likely to lead to greater improvements in BNP, NT-pro-BNP, and peak VO(2).

DESIGN

Individual patient meta-analysis.

METHODS

A systematic search was conducted of Medline (Ovid), Embase.com, Cochrane Central Register of Controlled Trials, and CINAHL (until July 2008) to identify randomized controlled trials of aerobic and/or resistance exercise training in systolic heart failure patients measuring BNP and/or NT-pro-BNP. Primary outcome measures were change in BNP, NT-pro-BNP, and peak VO2. Subanalyses were conducted to identify (1) patient groups that benefit most and (2) exercise programme parameters enhancing favourable changes in primary outcome measures.

RESULTS

Ten randomized controlled studies measuring BNP or NT-pro-BNP met eligibility criteria, authors provided individual patient data for 565 patients (313 exercise and 252 controls). Exercise training had favourable effects on BNP (-28.3%, p < 0.0001), NT-pro-BNP (-37.4%, p = < 0.0001), and peak VO(2) (17.8%, p < 0.0001). The analysis showed a significant change in primary outcome measures; moreover, change in BNP (r = -0.31, p < 0.0001) and NT-pro-BNP (r = -0.22, p < 0.0001) were correlated with peak VO(2) change.

CONCLUSION

Exercise training has favourable effects on BNP, NT-pro-BNP, and peak VO(2) in heart failure patients and BNP/NT-pro-BNP changes were correlated with peak VO(2) changes.

Limitations to high intensity exercise prescription in chronic heart failure patients

BACKGROUND

Interval training is recommended for chronic heart failure patients (CHF), but specific guidelines on setting appropriate workloads have not been fully established. The aim of this study was to compare a traditional method of interval training prescription with a protocol specifically designed for CHF.

METHODS

Ten CHF and 7 healthy controls performed 2 maximal incremental cycle tests to determine interval training workload; a standard test (10Wmin(-)(1)) and a steep test (25W.10(-)(s)). Peak work rate and oxygen uptake (VO(2 peak)) were determined. Training workloads were defined as 100% standard test and 50% steep test peak work rate.

RESULTS

Training workload determined from the standard test was higher than from the steep test in healthy controls (151 ± 17W vs 118 ± 13W; P<0.01), whereas in CHF there was no significant difference between methods (88 ± 10W vs 96 ± 9W; P>0.05). Steep test VO(2peak) reached 91 ± 5% of standard test VO(2 peak) in controls, and 99 ± 4% in CHF, with no significant differences between tests in either group.

CONCLUSION

Prescribing interval training from a standard test results in higher workloads than from a steep test in healthy individuals, but in CHF both methods prescribe similar workloads. However it should not be assumed that the two tests can be used interchangeably for CHF. This small-sized study raises issues about interval training prescription that may be hypothesis-generating for future larger-scale studies.

Heart rate recovery and oxygen kinetics after exercise in obstructive sleep apnea syndrome

BACKGROUND

Patients who suffer from obstructive sleep apnea (OSA) have a decreased exercise capacity and abnormal autonomic nervous function. However, the kinetics of early oxygen (O2) and heart rate recovery (HRR) have not been described.

MATERIALS AND METHODS

We evaluated 21 men with moderate to severe OSA (mean age: 48 +/- 11 yrs, mean apnea-hypopnea index [AHI]: 55 +/- 13) and without known heart disease and 10 healthy men matched for age and body mass index (BMI; controls). Men with OSA underwent overnight polysomnography, and both groups underwent symptom-limited incremental cardiopulmonary exercise testing (CPET). We recorded the CPET parameters including peak O2 uptake (VO2p), kinetics of early O2 recovery by the first degree slope of VO2 during the first minute (VO2/t slope), the time required for a 50% decline of VO2p during recovery (T(1/2)), and early heart rate recovery (HRR = HR at maximal exercise - HR at 1 min of recovery), as well as the chronotropic reserve to exercise ([CR] = [peak HR - resting HR/220 - age - resting HR] x 100). Patients with OSA had a lower VO2p (28.7 +/- 4.0 vs 34.7 +/- 6.2 mL/kg/min), VO2/t slope (1.04 +/- 0.3 vs 1.4 +/- 0.17 mL/kg/min2), and T(1/2) (74 +/- 10 vs 56 +/- 6 sec) compared to controls (all P < 0.001). In addition, both HRR and CR were lower in the OSA group (22.0 +/- 7.0 vs 31.0 +/- 6.0 bpm, P:0.003, and 79.0% +/- 15% vs 99.0% +/- 13.0%, P:0.01, respectively).

CONCLUSIONS

Patients with OSA demonstrate reduced exercise capacity, delayed oxygen kinetics, and reduced HRR. These data point to abnormal oxygen delivery and/or oxidative function of the peripheral muscles and impaired autonomic nervous activity in OSA patients.