Comparative effects of high intensity interval training versus moderate intensity continuous training on quality of life in patients with heart failure: Study protocol for a randomized controlled trial

Exercise-based cardiac rehabilitation for heart failure: effects on echocardiographic parameters and functional capacity: a randomized clinical trial

Introduction

Multiple comorbidities and physiological changes play a role in a range of heart failure (HF) conditions and influence the most effective approach to exercise-based rehabilitation. This research aimed to examine and compare the outcomes of concurrent exercise training, focusing on echocardiographic parameters and functional capacity of patients with heart failure with reduced ejection fraction (HFrEF).

Methods

In this randomized control trial, a total of 76 patients (average age: 68.2 ± 4.8 years) with HFrEF were randomly allocated into two groups: intervention group (IG, N = 38) and control group (CG, N = 38) that IG performed an 8-week concurrent exercise training (three aerobic and two resistance exercise sessions/week) and daily breathing exercises. Echocardiographic parameters (left ventricular ejection fraction, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, and functional capacity (6-minute walking test) were assessed before and the end of the study.

Results

The comparison of CG and IG showed that 6-min walking test (204.2 ± 28.72 vs. 273 ± 38.37) and ejection fraction (EF) (28.28 ± 4.39 vs. 37.23 ± 6.54) had increased, and left ventricle end-diastolic dimension (53.89 ± 4.73 vs. 46.71 ± 5.35) and left ventricle end-systolic dimension (45.55 ± 4.8 vs. 39 ± 5.26) had decreased after 8 weeks, respectively (P < 0/05).

Conclusion

In summary, this study provides compelling evidence that exercise-based cardiac rehabilitation can lead to meaningful improvements in echocardiographic parameters and functional capacity among older adults with HF, advocating for its broader implementation in clinical settings.

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.

High intensity interval training vs. moderate intensity continuous training on aerobic capacity and functional capacity in patients with heart failure: a systematic review and meta-analysis

Background

Exercise training is commonly employed as a efficacious supplementary treatment for individuals suffering from heart failure, but the optimal exercise regimen is still controversial. The objective of the review was to compare the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on the exercise capacity, cardiac function, quality of life (QoL) and heart rate among patients with heart failure with reduced ejection fraction.

Methods

A systematic search was performed using the following eight databases from their inception to July 5, 2023: PubMed, Web of Science, Embase, Cochrane Library, Clinical Trials, China Knowledge Network, Wan fang Data, and the China Biology Medicine databases. The meta-analysis results were presented as mean difference (MD) and 95% confidence interval (CI). The Cochrane Risk of Bias tool was used for the included studies. The Grading of Recommendations Assessment, Development, and Evaluations was used to assess the certainty of evidence.

Results

Thirteen randomized controlled trials were included in the study. The results showed that HIIT had a significant positive effect on peak oxygen uptake (MD = 1.78, 95% CI for 0.80-2.76), left ventricular ejection fraction (MD = 3.13, 95% CI for 1.25-5.02), six-minute walk test (MD = 28.13, 95% CI for 14.56-41.70), and Minnesota Living with Heart Failure Questionnaire (MD = -4.45, 95% CI for -6.25 to -2.64) compared to MICT. However, there were no statistically significant differences observed in resting heart rate and peak heart rate.

Conclusions

HIIT significantly improves peak oxygen uptake, left ventricular ejection fraction, six-minute walk test, and Minnesota Living with Heart Failure Questionnaire in patients with heart failure with reduced ejection fraction. Additionally, HIIT exhibits greater effectiveness in improving peak oxygen uptake among patients with lower body mass index.

Systematic Review Registration

https://www.doi.org/10.37766/inplasy2023.7.0100, identifier (INPLASY2023.7.0100).

Electromyogram Power Spectrum and Cardiac Function Changes After Combined Aerobic Interval Training and Inspiratory Muscle Training in Chronic Heart Failure Patients

Exercise intolerance and dyspnea are the major symptoms of patients with chronic heart failure (CHF) and are associated with a poor quality of life. In addition to impaired central hemodynamics, symptoms may be attributed to changes in peripheral skeletal muscles. This study aimed to evaluate the effects of aerobic interval training (AIT) combined with inspiratory muscle training (IMT) on cardiac and skeletal muscle function and on functional capacity and dyspnea in patients with CHF and inspiratory muscle weakness.Left ventricle ejection fraction was improved significantly after AIT and AIT & IMT with a high percentage of amelioration (17%, P < 0.042) in the combined group compared to the control group. Therefore, we showed a significant improvement in maximal voluntary isometric force, isometric endurance time, root mean square, and frequency median in both strength and endurance manipulations in the aerobic and combined group; however, the improvement was superior in the combined group compared to the control group. Significant amelioration was proved in functional capacity and dyspnea after all types of training but was performed at 18% higher in 6 minutes' walk test and 43% lower in dyspnea for the combined group compared to the control group.Combining AIT to IMT had optimized exercise training benefits in reversing the cardiac remodeling process and improving skeletal muscle function, functional capacity, and dyspnea in patients with CHF.

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.

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.

Effects of High-Intensity Interval vs. Moderate-Intensity Continuous Training on Cardiac Rehabilitation in Patients With Cardiovascular Disease: A Systematic Review and Meta-Analysis

Background

Studies have shown that high-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) for increasing peak oxygen uptake (VO_2peak) and reducing cardiovascular disease (CVD) and mortality. To our knowledge, previously published systematic reviews have neither compared different HIIT models with MICT nor investigated intervention frequencies of HIIT vs. MICT for purposes of improving cardiorespiratory fitness in patients with CVD.

Objective

The purpose of this meta-analysis was to compare the effects of different training models, intervention frequencies and weeks of HIIT vs. MICT on changes in cardiorespiratory fitness during cardiac rehabilitation (CR).

Methods

A systematic search was carried out for research articles on randomized controlled trials (RCTs) indexed in the PubMed, Cochrane Library, Web of Science, Embase and Scopus databases for the period up to December 2021. We searched for RCTs that compared the effect of HIIT vs. MICT on cardiorespiratory fitness in patients with CVD.

Results

Twenty-two studies with 949 participants (HIIT: 476, MICT: 473) met the inclusion criteria. Sensitivity analysis revealed that HIIT increased VO_2peak more than MICT (MD = 1.35). In the training models and durations, there was a greater increase in VO_2peak with medium-interval HIIT (MD = 4.02) and more than 12 weeks duration (MD = 2.35) than with MICT. There were significant improvements in VO_2peak with a HIIT frequency of 3 times/week (MD = 1.28). Overall, one minor cardiovascular and four non-cardiovascular adverse events were reported in the HIIT group, while six non-cardiovascular adverse events were reported in the MICT group.

Conclusion

HIIT is safe and appears to be more effective than MICT for improving cardiorespiratory fitness in patients with CVD. Medium-interval HIIT 3 times/week for more than 12 weeks resulted in the largest improvement in cardiorespiratory fitness during CR.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021245810, identifier: CRD42021245810.

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.

Entrenamiento intermitente de alta intensidad versus continuo en mujeres con hipertensión

Objetivo: comparar los efectos de la implementación de un programa de ejercicio continuo de mediana intensidad vs. un programa de ejercicio interválico de alta intensidad sobre los parámetros antropométricos y de condición física en mujeres hipertensas.Materiales y método: estudio experimental con pre y post prueba, realizado en 62 mujeres hipertensas divididas en 3 grupos: el primer grupo realizó ejercicio interválico de alta intensidad, el segundo hizo ejercicio continuo de mediana intensidad y el tercero es el grupo control. La intervención se realizó durante 12 semanas con una frecuencia semanal de 3 repeticiones. En todas las mujeres hipertensas se evaluó su condición física y características antropométricas.Resultados: posterior a la intervención, se encontraron diferencias estadísticamente significativas entre el grupo HiiT (high intensity interval training) y el grupo control en cuanto a las variables porcentaje de grasa (p = 0,014), densidad corporal (p = 0,014) e índice de conicidad [IC] (p = 0,003). Adicionalmente, se identificaron diferencias entre los dos grupos de ejercicio y el grupo control en las variables distancia recorrida (p = 0,04), flexibilidad en miembro superior derecho (p = 0,00) y fuerza en miembros inferiores (p = 0,01).Conclusiones: el estudio demostró que el ejercicio es una herramienta efectiva para mejorar la aptitud física de mujeres hipertensas. Sin embargo, no se encontraron diferencias en la efectividad entre el entrenamiento interválico de alta intensidad y el entrenamiento continuo.

Comparison of Treadmill and Cycle Ergometer Exercise During Cardiac Rehabilitation: A Meta-analysis

OBJECTIVE

To compare treadmill versus cycling-based exercise in cardiac rehabilitation (CR) on functional capacity (FC) outcomes.

DATA SOURCE

Databases were searched for randomized studies using single modality continuous exercise.

STUDY SELECTION

Studies implemented a continuous cycling or treadmill protocol for patients with either coronary artery disease (CAD) or chronic heart failure (CHF). The effect of single modality exercise on FC (VO₂peak) was analyzed. Differences in the effect of CR on FC was assessed between the mode subgroup (cycling vs treadmill) and disease state subgroup (CAD vs CHF) within both the cycling and treadmill groups.

DATA EXTRACTION

Data were extracted from 23 studies including 600 patients (mean age 60y, 86% men).

DATA SYNTHESIS

There was a significant difference in effect size between studies that used cycling, Hedges' g=0.85 (95% confidence interval [95% CI], 0.52-1.17; k=13) and studies that used treadmill exercise, Hedges' g=0.46 (95% CI, 0.22-0.70; k=8). Within cycling studies (n=14), FC was higher among CAD patients, Hedges' g=1.03 (95% CI, 0.65-1.42; k=9) compared to those with CHF, Hedges' g=0.40 (95% CI, 0.09-0.71; k=4, P<.001). Conversely, among treadmill studies (n=9), FC was higher among CHF patients, Hedges' g=0.94 (95% CI, 0.23-1.65; k=2) compared to CAD, Hedges' g=0.33 (95% CI, 0.19-0.47; k=5; P<.01).

CONCLUSIONS

According to identified studies, when cycling was the primary mode of exercise in CR, there was larger change in FC compared to treadmill exercise. In addition, CAD patients experienced greater gains in FC when cycling was the primary mode of exercise in CR, while CHF patients benefited more from treadmill-based exercise programs.

The effect of inspiratory muscle training on fatigue and dyspnea in patients with heart failure: A randomized, controlled trial

AIM

Fatigue and dyspnea are debilitating symptoms in patients with heart failure (HF). The purpose of this study was to evaluate the effects of inspiratory muscle training (IMT) on dyspnea, fatigue and the New York Heart Association (NYHA) functional classification in patients with HF.

METHODS

In this prospective, randomized, controlled trial, 84 patients with HF (NYHA classes II-III/IV) with a mean age of 56.62 ± 9.56 years were randomly assigned to a 6-week IMT (n = 42) or a sham IMT (n = 42) program. The IMT was performed at 40% of the maximal inspiratory pressure (MIP) in the IMT group and at 10% in the sham group. The main outcomes were assessed at baseline and after the intervention and included dyspnea severity scale (Modified Medical Research Council [MMRC], Fatigue Severity Scale [FSS] and the NYHA functional classification (based on the presenting symptoms).

RESULTS

The between-group analysis showed significant improvements in dyspnea, fatigue and the NYHA functional classification in the IMT group compared to the sham group (P < .05). The within-group analysis showed significant improvements in dyspnea (from 2.63 ± 0.79 to 1.38 ± 0.66, P < .001), fatigue (from 43.36 ± 8.5 to 28.95 ± 9.11, P < .001) and the NYHA functional classification (from 2.73 ± 0.5 to 2.1 ± 0.6, P = .001) in the IMT group, while fatigue and dyspnea increased significantly in the sham group.

CONCLUSIONS

The 6-week home-based IMT was found to be an effective and safe tool for reducing dyspnea and fatigue and improving the NYHA functional classification.

High-Intensity Interval Training in Cardiac Rehabilitation

Recently, high-intensity interval training (HIIT) has been recognized as a safe and effective alternative to moderate-intensity continuous training for older patients with cardiovascular disease (CVD) in cardiac rehabilitation settings in an effort to improve health outcomes. This brief review considers general principles and suggestions for prescription of HIIT for older patients with CVD, specific challenges pertaining to older adults, the physiologic mechanisms by which HIIT contributes to improvements in peak Vo₂, and the effects of HIIT on cardiovascular health in older patients with coronary artery disease and heart failure.

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.

High intensity interval training exercise as a novel protocol for cardiac rehabilitation program in ischemic Egyptian patients with mild left ventricular dysfunction

Background

Exercise-based Cardiac rehabilitation (CR) plays a major role in reducing mortality and morbidity in patients with coronary artery disease (CAD). The standard protocol is usually of moderate intensity exercise. High-intensity interval training (HIIT) consists of alternating periods of intensive aerobic exercise with periods of passive or active moderate/mild intensity recovery.

Aim

This study aimed to assess HIIT program for ischemic patients attending CR after percutaneous coronary intervention (PCI) who have mild left ventricular dysfunction and to compare its effect on the functional capacity and quality of life with standard exercise CR program.

Patients and methods

Our study included 40 patients with documented CAD, who participated in the outpatient CR program in Ain Shams University hospital (Al-Demerdash Hospital) divided into two equal groups, each included 20 patients. Group A included the patients who underwent standard cardiac rehabilitation program, while group B joined the high intensity interval training exercise protocol.

Results

Groups A and B showed significant improvement in all items of comparison; especially functional capacity, lipid profile and quality of life. Group B showed better improvements in the emotional well-being items of QOL parameters.

Conclusion

We emphasize the positive effects of exercise-based CR program on patients with CAD and mild left ventricular dysfunction after PCI. The novel high intensity cardiac training proved to be safe and at least as beneficial as the standard moderate intensity cardiac training protocols, with better quality of life improvement.

Exercise training as S-Klotho protein stimulator in sedentary healthy adults: Rationale, design, and methodology

Aims

The secreted form of the α-Klotho gene (S-Klotho), which is considered a powerful biomarker of longevity, makes it an attractive target as an anti-ageing therapy against functional decline, sarcopenic obesity, metabolic and cardiovascular diseases, osteoporosis, and neurodegenerative disorders. The S-Klotho plasma levels could be related to physical exercise inasmuch physical exercise is involved in physiological pathways that regulate the S-Klotho plasma levels. FIT-AGEING will determine the effect of different training modalities on the S-Klotho plasma levels (primary outcome) in sedentary healthy adults. FIT-AGEING will also investigate the physiological consequences of activating the klotho gene (secondary outcomes).

Methods

FIT-AGEING will recruit 80 sedentary, healthy adults (50% women) aged 45–65 years old. Eligible participants will be randomly assigned to a non-exercise group, i.e. the control group, (n = 20), a physical activity recommendation from World Health Organization group (n = 20), a high intensity interval training group (n = 20), and a whole-body electromyostimulation group (n = 20). The laboratory measurements will be taken at the baseline and 12 weeks later including the S-Klotho plasma levels, physical fitness (cardiorespiratory fitness, muscular strength), body composition, basal metabolic rate, heart rate variability, maximal fat oxidation, health blood biomarkers, free-living physical activity, sleep habits, reaction time, cognitive variables, and health-related questionnaires. We will also obtain dietary habits data and cardiovascular disease risk factors.

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

OBJECTIVE

The aim of this study was to investigate the effects of high intensity interval training (HIIT) versus moderate intensity continuous training (MICT) in heart failure patients with reduced ejection fraction (HFrEF).

BACKGROUND

Despite the well-known positive effects of exercise in heart failure patients, the best mode of exercise is still under discussion.

METHODS

We searched Pubmed/MEDLINE, Cochrane Central Register of Controlled Trials, PEDro data base, and SciELO (from the earliest date available to October 2017) for randomized controlled trials that evaluated the effects of HIIT versus MICT in HFrEF patients. Weighted mean differences (WMD) with 95% confidence interval (CI) were calculated, and heterogeneity was assessed using the I² test.

RESULTS

13 studies met the study criteria, including 411 patients. Compared to MICT, HIIT resulted in improvement in Peak VO₂ WMD (1.35 mL·kg^-1·min^-1 95% CI: 0.03 to 2.64 N = 411). HIIT resulted in no difference in VE/VCO₂ slope WMD (-1.21 95% CI: -3.0 to 0.58 N = 135), and quality of life measured by Minnesota Living with Heart Failure questionnaire WMD (1.19 95% CI: -5.81 to 8.19 N = 79). Sub-group analyses comparing studies with and without isocaloric exercise training protocol also showed a nonsignificant difference in peak VO₂ for participants in the HIIT group compared with MICT group.

CONCLUSIONS

HIIT improves peak VO₂ and should be considered as a component of care of HFrEF patients. However, its superiority versus MICT disappears when isocaloric protocols are compared. An important caveat is uncertainty and variation of actual training intensities compared to program targets.

Does low volume high-intensity interval training elicit superior benefits to continuous low to moderate-intensity training in cancer survivors?

AIM

To determine the impact of low volume high-intensity interval training (LVHIIT) and continuous low to moderate-intensity exercise training (CLMIT) on cardiovascular disease (CVD) risk and health outcomes in cancer survivors.

METHODS

Sedentary cancer survivors (n = 75, aged 51 ± 12 year) within 24 months of diagnosis, were randomised into three groups for 12 wk of LVHIIT (n = 25), CLMIT (n = 25) or control group (n = 25). The exercise intervention involved 36 sessions (three sessions per week). The LVHIIT group performed 7 x 30 s intervals (≥ 85% predicted maximal heart rate) with a 60 s rest between intervals, and the CLMIT group performed continuous aerobic training for 20 min (≤ 55% predicted maximal heart rate) on a stationary bike. Outcome variables were measured at baseline and at 12 weeks and analysed using a 3 x 2 (group x time) repeated measures ANCOVA to evaluate main and interaction effects.

RESULTS

Significant improvements (time) were observed for seven of the 22 variables (ES 0.35-0.97, P ≤ 0.05). There was an interaction effect (P < 0.01) after 12 wk in the LVHIIT group for six-minute walk test (P < 0.01; d = 0.97; 95%CI: 0.36, 1.56; large), sit to stand test (P < 0.01; d = -0.83; 95%CI: -1.40, -0.22; large ) and waist circumference reduction (P = 0.01; d = -0.48; 95%CI: -1.10, 0.10; medium). An interaction effect (P < 0.01) was also observed for quality of life in both the LVHIIT (d = 1.11; 95%CI: 0.50, 1.72; large) and CLMIT (d = 0.57; 95%CI: -0.00, 1.20; moderate) compared with the control group (d = -0.15; 95%CI: -0.95, 0.65; trivial).

CONCLUSION

Low-volume high-intensity training shows promise as an effective exercise prescription within the cancer population, showing greater improvements in cardio-respiratory fitness, lower body strength and waist circumference compared with traditional CLMIT and control groups. Both LVHIIT and CLMIT improved quality of life. A proposed benefit of LVHIIT is the short duration (3 min) of exercise required, which may entice more cancer survivors to participate in exercise, improving health outcomes and lowing the risk of CVD.

High-intensity exercise interventions in cancer survivors: a systematic review exploring the impact on health outcomes

PURPOSE

There is an increasing body of evidence underpinning high-intensity exercise as an effective and time-efficient intervention for improving health in cancer survivors. The aim of this study was to, (1) evaluate the efficacy and (2) the safety of high-intensity exercise interventions in improving selected health outcomes in cancer survivors.

METHODS

Design Systematic review. Data sources Google Scholar and EBSCO, CINAHL Plus, Computers and Applied Sciences Complete, Health Source-Consumer Edition, Health Source: Nursing/Academic Edition, MEDLINE, Web of Science and SPORTDiscuss from inception up until August 2017. Eligibility criteria Randomized controlled trials of high-intensity exercise interventions in cancer survivors (all cancer types) with health-related outcome measures. The guidelines adopted for this review were the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA).

RESULTS

The search returned 447 articles, of which nine articles (n = 531 participants mean, age 58 ± 9.5 years) met the eligibility criteria. Exercise interventions of between 4 and 18 weeks consisting of high-intensity interval bouts of up to 4-min were compared with a continuous moderate intensity (CMIT) intervention or a control group. High-intensity exercise interventions elicited significant improvements in VO2 max, strength, body mass, body fat and hip and waist circumference compared with CMIT and/or control groups. The studies reviewed showed low risk in participating in supervised high-intensity exercise interventions. Mixed mode high-intensity interventions which included both aerobic and resistance exercises were most effective improving the aerobic fitness levels of cancer survivors by 12.45-21.35%, from baseline to post-intervention.

CONCLUSION

High-intensity exercise interventions improved physical and physiological health-related outcome measures such as cardiovascular fitness and strength in cancer survivors. Given that high-intensity exercise sessions require a shorter time commitment, it may be a useful modality to improve health outcomes in those who are time poor. The risk of adverse events associated with high-intensity exercise was low.

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.

Comparing exercise training modalities in heart failure: A systematic review and meta-analysis

Exercise training (ET) is suggested to improve exercise capacity, prognosis, quality of life (QOL) and functional modifications of the heart in patients with heart failure (HF). However, it is not clear which modality is best. In order to assess the effectiveness of different ET modalities on prognostic cardiopulmonary exercise test (CPET) parameters, QOL and left ventricular remodeling, a systematic review and meta-analysis was performed. Randomized clinical trials (RCTs) were selected in three databases. The primary outcome data were peak oxygen uptake, ventilation over carbon dioxide slope, oxygen uptake efficiency slope, exercise oscillatory ventilation, rest and peak pulmonary end-tidal CO2. Secondary variables were QOL, left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDD). Twenty RCTs (n=811) met the a priori stated inclusion criteria. Studies were categorized into four different groups: "interval training (IT1) versus combined interval and strength training (IT1S)" (n=156), "continuous training (CT1) versus combined continuous and strength training (CT1S)" (n=130), "interval training (IT2) versus continuous training (CT2)" (n=501) and "continuous training (CT3) versus strength training (S3)" (n=24). No significant random effects of exercise modality were revealed assessing the CPET parameters. There was a significant improvement in QOL applying CT1S (P<0.001). Comparing IT2 with CT2, LVEDD and LVEF were significantly improved favoring IT2 (P<0.001). There is some evidence to support that interval training is more effective to improve LVEF and LVEDD. The fact that patients with HF are actively involved in any kind of ET program seems sufficient to improve the prognosis, QOL and anatomic function.

Mitochondrial Therapies in Heart Failure

The current therapy for patients with stable systolic heart failure is largely limited to treatments that interfere with neurohormonal activation. Critical pathophysiological hallmarks of heart failure are an energetic deficit and oxidative stress, and both may be the result of mitochondrial dysfunction. This dysfunction is not (only) the result of defect within mitochondria per se, but is in particular traced to defects in intermediary metabolism and of the regulatory interplay between excitation-contraction coupling and mitochondrial energetics, where defects of cytosolic calcium and sodium handling in failing hearts may play important roles. In the past years, several therapies targeting mitochondria have emerged with promising results in preclinical models. Here, we discuss the mechanisms and results of these mitochondria-targeted therapies, but also of interventions that were not primarily thought to target mitochondria but may have important impact on mitochondrial biology as well, such as iron and exercise. Future research should be directed at further delineating the details of mitochondrial dysfunction in patients with heart failure to further optimize these treatments.