High-intensity Interval Training Dosage for Heart Failure and Coronary Artery Disease Cardiac Rehabilitation. A Systematic Review and Meta-analysis

Effects of Different Exercise Interventions on Cardiorespiratory Fitness, as Measured by Peak Oxygen Consumption in Patients with Coronary Heart Disease: An Overview of Systematic Reviews

BACKGROUND

Exercise is an important component of rehabilitation care for people with coronary heart disease (CHD).

OBJECTIVES

The aim of this study was to critically analyze and summarize the existing evidence from published systematic reviews (SRs) and meta-analyses of randomized controlled trials (RCTs) that have evaluated the effects of different types of exercise interventions on cardiorespiratory fitness, as measured by peak oxygen consumption in people with CHD.

METHODS

Electronic databases (Cochrane Library, Medline/PubMed, EMBASE, and PEDro) were searched for SRs of exercise interventions of people with CHD. Two reviewers assessed the quality of SRs using the AMSTAR-2 tool and evaluated the strength of evidence quality with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system for relevant outcome measures. Mean difference (MD) and 95% confidence intervals (CIs) were calculated.

RESULTS

Thirty-one SRs (with 125 RCTs) met the study criteria, including 33,608 patients. Compared with usual care, continuous aerobic exercise produced an improvement in peak oxygen consumption, MD of 3.8 mL kg-1 min-1 (95% CI: 3.204.4, I2 = 67%); high-intensity interval training, MD 6.1 mL kg-1 min-1 (95% CI: 0.4-11.8, I2 = 97%); resistance training, MD of 2.1 mL kg-1 min-1 (95% CI: 0.98-3.2, I2 = 60%); combined aerobic and resistance training, MD of 3.0 mL kg-1 min-1 (95% CI: 2.5-3.4, I2 = 0%); and water-based exercise, MD of 4.4 mL kg-1 min-1 (95% CI, 2.1-6.7; I2 = 2%).

CONCLUSION

Exercise interventions improve peak oxygen consumption in people with CHD. However, there was moderate to very-low certainty for the evidence found.

HRV-guided training vs traditional HIIT training in cardiac rehabilitation: a randomized controlled trial

High-intensity interval training is the gold standard for cardiac rehabilitation although current revascularization therapy focuses on the recovery of autonomic nervous system balance through heart rate variability (HRV). The main objective was to analyze the effect of HRV-guided training versus high-intensity interval training on cardiorespiratory fitness, heart rate variability, quality of life, and training volume at high intensity, as well as exercise adherence, safety, and feasibility in ischemic patients. This is an 8-week cluster randomized controlled trial with an HRV-based training group (HRV-G) and a traditional HIIT group (HIIT-G). Maximal oxygen consumption, heart rate, and blood pressure were measured during the Bruce protocol treadmill test. HRV was measured with the HRV4Training application, and quality of life with the MacNew QLMI. The repeated measures ANCOVA was used with the age and the baseline scores as covariables. Forty-six patients (mean age 55 ± 11.03 years) were randomized and assigned either to HRV-G (n = 23) or HIIT-G (n = 23). Both groups improved maximal oxygen consumption and METS (P > .05). However, the resting systolic blood pressure was lower in HRV-G (4.3 ± 1.2 mmHg, P = .05). In HRV-G, the resting diastolic, maximal diastolic, and systolic blood pressure decreased (5.4 ± 5.96 mmHg, P = .007; 11.4 ± 12.46 mmHg, P = .005; and 5 ± 5.98 mmHg, P = .013, respectively) whereas the recovery heart rate increased significantly (-21.5 ± 23.16 beats/min, P = .003). The LnrMSSDcv ([LnrMSSDSD/LnrMSSDMEAN] × 100) was lower in HRV-G (1.23 ± 0.91 mmHg, P = .03) while the training volume at high intensity was higher in HIIT-G (31.4 ± 29.2 min, P = .024). HRV-guided training presents a better cardioprotective effect than HIIT-G at a lower high-intensity training volume.

High-intensity interval training versus moderate-intensity continuous training in patients with heart failure: a systematic review and meta-analysis

The effects of high-intensity interval training (HIIT) in patients with heart failure (HF) remain controversial. This systematic review and meta-analysis aimed to examine the efficacy of HIIT versus moderate-intensity continuous aerobic training (MCT) on exercise tolerance in patients with HF. We searched for studies published up to 4 March 2022 in Embase, MEDLINE, PubMed, and the Cochrane Library with no limitations on data, language, or publication status. We included randomized controlled trials comparing the efficacy of HIIT and MCT on peak oxygen uptake (VO₂), as a measure of exercise tolerance. We pooled the data on peak VO₂, compared HIIT to MCT, and conducted a sub-analysis if there was heterogeneity in the result. We identified 15 randomized controlled trials with 557 patients. Our meta-analysis showed that participants who underwent HIIT achieved a significantly higher peak VO₂ than those who underwent MCT (mean difference 1.46 ml/kg/min, 95% confidence interval 0.39 to 2.53; participants = 557; studies = 15; I² = 65.7%; very low-quality evidence). The meta-regression analysis, conducted as a sub-analysis to explore possible causes of heterogeneity, revealed that the difference in peak VO₂ between HIIT and MCT was inversely associated with body mass index (r =  - 0.508, p = 0.028, 95% confidence interval - 0.95 to - 0.07). Our systematic review showed that HIIT achieved a higher peak VO₂ than MCT in patients with HF. In addition, HIIT may be more effective in improving exercise tolerance in patients with low body mass index.

Global trends and frontiers in research on exercise training for heart failure: a bibliometric analysis from 2002 to 2022

Background

Heart failure is a common cardiovascular disease that imposes a heavy clinical and economic burden worldwide. Previous research and guidelines have supported exercise training as a safe, effective, and cost-efficient treatment to intervene in heart failure. The aim of this study was to analyze the global published literature in the field of exercise training for heart failure from 2002 to 2022, and to identify hot spots and frontiers within this research field.

Methods

Bibliometric information on literature on the topic of exercise training for heart failure published between 2002 and 2022 was searched and collected in the Web of Science Core Collection. CiteSpace 6.1.R6 (Basic) and VOSviewer (1.6.18) were applied to perform bibliometric and knowledge mapping visualization analyses.

Results

A total of 2017 documents were retrieved, with an upward-stable trend in the field of exercise training for heart failure. The US authors were in the first place with 667 documents (33.07%), followed by Brazilian authors (248, 12.30%) and Italian authors (182, 9.02%). The Universidade de São Paulo in Brazil was the institution with the highest number of publications (130, 6.45%). The top 5 active authors were all from the USA, with Christopher Michael O'Connor and William Erle Kraus publishing the most documents (51, 2.53%). The International Journal of Cardiology (83, 4.12%) and the Journal of Applied Physiology (78, 3.87%) were the two most popular journals, while Cardiac Cardiovascular Systems (983, 48.74%) and Physiology (299, 14.82%) were the two most popular categories. Based on the results of keyword co-occurrence network and co-cited reference network, the hot spots and frontiers of research in the field of exercise training for heart failure were high-intensity interval training, behaviour therapy, heart failure with preserved ejection fraction, and systematic reviews.

Conclusion

The field of exercise training for heart failure has experienced two decades of steady and rapid development, and the findings of this bibliometric analysis provide ideas and references for relevant stakeholders such as subsequent researchers for further exploration.

Acute physiological responses to high-intensity interval exercise in patients with coronary artery disease

PURPOSE

Time spent closer to maximal effort during exercise is a potent stimulus for cardiorespiratory adaptations. The primary purpose was to determine which high-intensity interval exercise (HIIE) protocol provided the greatest physiological stimulus by comparing time spent ≥ 90% peak oxygen consumption (V̇O₂peak) and heart rate reserve (HRR) in patients with coronary artery disease (CAD) in response to 3 HIIE protocols and the exercise standard of care, moderate-intensity continuous exercise (MICE). A secondary purpose was to assess protocol preference.

METHODS

Fifteen patients with CAD (6 females, 67 ± 6 years) underwent measurements of V̇O₂ and heart rate during MICE and three HIIE protocols all performed on a treadmill. The HIIE protocols included one with long intervals (4 × 4-min), short intervals (10 × 1-min), and an adapted version of the 4 × 4 [Toronto Rehabilitation Institute Protocol, (TRIP)]. Time spent ≥ 90% V̇O₂peak and HRR were compared.

RESULTS

Time spent ≥ 90% V̇O₂peak was higher during 4 × 4 (6.3 ± 8.4 min) vs. MICE (1.7 ± 3.9 min; P = 0.001), while time spent ≥ 90% HRR was higher during 4 × 4 (6.0 ± 5.3 min) vs. MICE (0.1 ± 0.2 min; P < 0.001) and 10 × 1 (0.7 ± 0.8 min; P = 0.016). TRIP had similar responses as 10 × 1 and MICE. The 10 × 1 was the most preferred protocol and the 4 × 4 was the least preferred protocol.

CONCLUSION

Longer intervals (4 × 4) provided the greatest physiological stimulus compared to the exercise standard of care and shorter intervals. However, this protocol was least preferred which may impact exercise adherence. Although the physiological stimulus is important to maximize training adaptations, exercise preferences and attitudes should be considered.

Associations of physical activity with cognitive function and daily physical function among Chinese individuals with heart disease: A cross-sectional study

Background

To investigate the associations between different dimensions of physical activity (PA), cognitive function, and daily physical function in Chinese individuals with heart disease.

Materials and methods

This study included 2,792 individuals from the China Health and Retirement Longitudinal Study conducted in 2015. Physical activity (PA) was divided into vigorous PA (VPA), moderate PA (MPA), and light PA (LPA). Linear and logistic regression models were established to assess the associations among the indicators.

Results

Compared with taking no PA, MPA, and VPA at a frequency of 6-7 d/w had lower risks of impaired daily physical function (OR = 0.47, 95% CI: 0.25, 0.91; OR = 0.57, 95% CI: 0.37, 0.88) and higher cognitive function scores (β = 1.22, 95% CI: 0.42, 2.03; β = 1.08, 95% CI: 0.43, 1.73), while VPA at 3-5 d/w had lower cognitive function scores (β = -1.96, 95% CI: -3.51, -0.40). Light PA (LPA) with a duration of 30-119 min/d had a lower risk of impaired daily physical function (OR = 0.59, 95% CI: 0.36, 0.97). Moderate PA (MPA) and VPA of 30-119 min/d had higher cognitive function scores (β = 1.43, 95% CI: 0.49, 2.37; β = 1.30, 95% CI: -0.56, 2.06). The 1,800-2,999 METs had the lowest risks of impaired daily physical function and the highest cognitive function scores (OR = 0.18, 95% CI: 0.04, 0.75; β = 2.94, 95% CI: 1.67, 4.21).

Conclusion

Moderate PA (MPA) and LPA with a frequency of 6-7 d/w and a duration of 30-119 min/d, and PA in 1,800-2,999 MET min/week were most closely related to better cognitive and daily physical function, while VPA (3-5 d/w; ≥300 min/w) may be related to low cognition, but high-quality research is necessary to prove causality.

Trial registration

IRB00001052-11015.

HRV-Guided Training for Elders after Stroke: A Protocol for a Cluster-Randomized Controlled Trial

There are many consequences associated with having a stroke, all of which are important factors affecting long-term rehabilitation outcomes; these become important health issues for those of advanced age and require dedicated health strategies. High-intensity interval training (HIIT) is an effective training protocol used in cardiac rehabilitation programs; however, owing to the inter-individual variability in physiological responses to training associated with cardiovascular diseases, the exercise regimen given to each patient should be closely controlled and individualized to ensure the safety and efficiency of the exercise program. Heart rate variability (HRV) is currently being used for this purpose, as it is closely linked to parasympathetic nervous system activation, with high HRV scores associated with good cardiovascular adaptation. The objective of this protocol is to determine the effect of HIIT compared to HRV-guided training in terms of cardiorespiratory fitness, heart rate variability, functional parameters, body composition, quality of life, inflammatory markers, and cognitive function in patients who have had a stroke, as well as to assess the feasibility of patients undertaking an 8-week cardiac rehabilitation program, evaluating its safety and their adherence. The proposed protocol involved cluster-randomized controlled design in which the post-stroke patients are assigned either to an HRV-based training group (HRV-G) or a HIIT-based training group (HIIT-G). HIIT-G will train according to a predefined training program, whereas HRV-G will train depending on the patients' daily HRV. The outcomes considered are peak oxygen uptake (VO_2peak), endothelial and work parameters, heart rate variability, functional parameters, relative weight and body fat distribution, quality of life, inflammatory markers and cognitive function, as well as exercise adherence, feasibility, and safety. It is expected that this HRV-guided training protocol will improve functional performance in patients following a stroke and be safer, more feasible, and generate improved adherence relative to HIIT, providing an improved strategy for to optimize cardiac rehabilitation interventions.

Effect of Early Exercise Rehabilitation on Cardiopulmonary Function and Quality of Life in Patients after Coronary Artery Bypass Grafting

The purpose of this study was to analyze the effect of early exercise rehabilitation on cardiopulmonary function and quality of life in patients after coronary artery bypass grafting (CABG). Eighty patients with coronary heart disease who underwent CABG from April 2020 to April 2022 were divided into the study group (n = 40) and control group (n = 40). The control group was given conventional treatment and routine care after CABG, and the study group received early exercise rehabilitation according to the control group. The cardiac function indexes, 6-minute walking test (6MWT), and cardiopulmonary function indexes and quality of life of the two groups were compared before and after the intervention, and the length of hospitalization and hospital costs as well as the occurrence of pulmonary complications in both groups were recorded. Left ventricular ejection fraction (LVEF) was significantly higher (P < 0.05), and left ventricular end-diastolic dimension (LVEDD) and left ventricular end-systolic diameter (LVESD) were significantly lower (P < 0.05) in the study group than in the control group after the intervention; 6MWT, maximal oxygen consumption (VO2max), and anaerobic threshold (AT) were significantly higher (P < 0.05) in the study group than in the control group after the intervention; physical function (PF), role physical (RP), general health (GH), and role emotional (RE) dimension scores were significantly higher (P < 0.05) in the study group compared with the control group after the intervention The differences in the scores of the remaining dimensions were not statistically significant (P > 0.05); the total hospitalization time in the test group was significantly shorter than that in the control group (P < 0.05), the hospitalization cost was significantly less than that in the control group (P < 0.05), and the total incidence of pulmonary infection and hypoxemia was significantly lower than that in the control group (P < 0.05). Early exercise rehabilitation can effectively improve cardiopulmonary function and exercise tolerance and improve the quality of life of patients after CABG.

Correlation between Cardiac Ultrasound-Related Indicators and Cardiac Function in Patients with Coronary Heart Disease and Heart Failure

Objective

The purpose of this paper is to analyse the correlation between cardiac ultrasound-related indicators and cardiac function in patients with coronary heart disease and heart failure.

Methods

In this experiment, a total of 160 patients with coronary heart disease and heart failure who were diagnosed and treated in our hospital from June 2019 to March 2021 were recruited as the study group. All were examined by colour Doppler ultrasound instrument, SPSS statistical software was used to analyse the data obtained, and Spearman correlation was used to analyse the correlation between cardiac ultrasound-related indicators and cardiac function in patients with coronary heart disease and heart failure.

Results

In the study group, there were 68 patients with grade II cardiac function, accounting for 42.50%; 74 patients with grade III, accounting for 46.25%; and 18 patients with grade IV, accounting for 11.25%. The ultrasound parameters of the patients in the study group were profiled and calculated, and then statistically analysed with cardiac function grading. Cardiac function classification was significantly positively correlated with LVMI, LAD, and LVEDd (r = 0.689/0.915/0.928, P=0.001) and significantly negatively correlated with CI, LVFS, and LVEF (r = −0.689/−0.878/−0.912), P=0.001).

Conclusion

Cardiac ultrasound-related indicators are associated with patients with coronary heart disease and heart failure. With the decline of cardiac function in patients with coronary heart disease and heart failure, the patient's condition is aggravated. Therefore, cardiac ultrasound-related indicators play a major role in the diagnosis of clinical disease progression.

The Effects of High-Intensity Interval Training on Exercise Capacity and Prognosis in Heart Failure and Coronary Artery Disease: A Systematic Review and Meta-Analysis

Objective

The purpose of this study is to compare the effects of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on exercise capacity and several prognostic markers in patients with coronary artery disease (CAD) and heart failure (HF).

Methods

This systematic review is registered on the INPLASY website (number: INPLASY202080112). We conducted a comprehensive search in eight databases of literature before September 13, 2019. Trials comparing HIIT and MICT in participants with CAD or HF aged 52–78 years were included. Exercise capacity (peak oxygen consumption (peak VO₂)) and prognostic markers, such as the anaerobic threshold (AT), minute ventilation/carbon dioxide production (VE/VCO₂) slope, left ventricular ejection fraction (LVEF), and prognostic value of the predicted VO₂ max per cent (the predicted VO₂ peak (%)) were examined.

Results

A total of 15 studies were included comprising 664 patients, 50% of which were male, with an average age of 60.3 ± 13.2 years. For patients with CAD, HIIT significantly improved peak VO₂ values (95% CI 0.7 to 2.11) compared with MICT, but peak VO₂ values in patients with HF did not seem to change. For training lasting less than eight weeks, HIIT significantly improved peak VO₂ values (95% CI 0.70 to 2.10), while HIIT lasting 12 weeks or longer resulted in a modestly increased peak VO₂ value (95% CI 0.31 to 5.31). High-intensity interval training significantly increased the AT when compared with MICT (95% CI 0.50 to 1.48). High-intensity interval training also caused a moderate increase in LVEF (95% CI 0.55 to 5.71) but did not have a significant effect on the VE/VCO₂ slope (95% CI −2.32 to 0.98) or the predicted VO₂ peak (95% CI −2.54 to 9.59) compared with MICT.

Conclusions

High-intensity interval training is an effective therapy for improving peak VO₂ values in patients with CAD. High-intensity interval training in the early stage (eight weeks or fewer) is superior to MICT. Finally, HIIT significantly improved prognostic markers, including the AT and LVEF in patients with CAD and 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 High-Intensity Interval Training (HIIT) on Fall Risk Factors in Healthy Older Adults: A Systematic Review

High-intensity interval training (HIIT) improves functional capacity, muscle power and physical performance in older adults with and without comorbidities. The aim of this study was to explore the effectiveness of HIIT as a method for reducing major fall risk factors (balance, muscle strength and physical activity) in older adults. A systematic literature search was conducted following the PRISMA guidelines. A computerized search was conducted using electronic databases (PubMed, CINAHL, Cochrane Library, APA PsycInfo, Web of Science, Scopus, PEDro, and AgeLine) published up to July 2021. Eleven papers (9 studies) of moderate quality (mean of 5.5 in Pedro scale) involving 328 healthy older adults met the inclusion criteria. Studies were characterized by high heterogeneity in terms of methodology, HIIT modality and protocol, subject characteristics, and outcome measures. Results indicate that HIIT cannot be recommended as a single modality for fall prevention in older adults due to insufficient data and no consensus among the studies. HIIT appears to be a safe and well-tolerated supplement to proven fall prevention programs, due to its effects on lower limb strength reflected in functional performance tests, and on dynamic balance and subjective balance perception. However, caution is warranted following HIIT, especially after the first session, due to possible temporary instability.

Cardiac rehabilitation and its essential role in the secondary prevention of cardiovascular diseases

Cardiovascular diseases are the most common causes of mortality worldwide. They are frequently the reasons for patient hospitalization, their incapability for work, and disability. These diseases represent a significant socio-economic burden affecting the medical system as well as patients and their families. It has been demonstrated that the etiopathogenesis of cardiovascular diseases is significantly affected by lifestyle, and so modification of the latter is an essential component of both primary and secondary prevention. Cardiac rehabilitation (CR) represents an efficient secondary prevention model that is especially based on the positive effect of regular physical activity. This review presents an overview of basic information on CR with a focus on current trends, such as the issue of the various training modalities, utilization, and barriers to it or the use of telemedicine technologies. Appropriate attention should be devoted to these domains, as CR continues evolving as an effective and readily available intervention in the future.

High-Intensity Interval Circuit Training Versus Moderate-Intensity Continuous Training on Cardiorespiratory Fitness in Middle-Aged and Older Women: A Randomized Controlled Trial

High-intensity interval training (HIIT) has similar or better effects than moderate-intensity continuous training (MICT) in increasing peak oxygen consumption (VO_2max), however, it has not been studied when HIIT is applied in a circuit (HIICT). The aim of this study was to compare the effects of a HIICT versus MICT on VO_2max estimated (VO_2max-ES), heart rate (HR) and blood pressure (BP) of middle-aged and older women. A quasi-experimental randomized controlled trial was used. Fifty-four women (67.8 ± 6.2 years) were randomized to either HIICT (n = 18), MICT (n = 18) or non-exercise control group (CG; n = 18) for 18 weeks. Participants in HIICT and MICT trained two days/week (one hour/session). Forty-one participants were assessed (HIICT; n = 17, MICT; n = 12, CG; n = 12). Five adverse events were reported. Cardiorespiratory fitness, HR and BP were measured. The tests were performed before and after the exercise intervention programs. VO_2max-ES showed significant training x group interaction, in which HIICT and MICT were statistically superior to CG. Moreover, HIICT and MICT were statistically better than CG in the diastolic blood pressure after exercise (DBP_ex) interaction. For the systolic blood pressure after exercise (SBP_ex), HIICT was statistically better than CG. In conclusion, both HIICT and MICT generated adaptations in VO_2max-ES and DBP_ex. Furthermore, only HIICT generated positive effects on the SBP_ex. Therefore, both training methods can be considered for use in exercise programs involving middle-aged and older women.

Different continuous training modalities result in distinctive effects on muscle structure, plasticity and function

The effects of training on muscle structure are dependent on adaptive changes induced by different intensities of physical exercise. Evidence has shown that aerobic training is able to induce adaptive changes to muscle structure based on intensity. The aim of the present study was to investigate the effects of different methods of continuous aerobic training in mice using functional, morphological and biomolecular approaches. The continuous aerobic training methods used in the present study were uniform continuous training (UC), varying continuous training (VC) and progressive continuous training (PC). Mice were made to run 3 times a week for 12 weeks on a motorized RotaRod, following one of the three different training methods at different speeds. The results of the present study demonstrated that the various training methods had different effects on sarcomere length. Ultrastructural analysis demonstrated that UC training resulted in a shortening of sarcomere length, PC training resulted in an elongation of sarcomere length and VC training showed similar sarcomere length when compared with the control sedentary group. Additionally, succinate dehydrogenase complex flavoprotein subunit A levels in muscle tissue following VC training were higher compared with UC and PC training. Overall, the present study showed that varying exercise methods resulted in different types of muscle plasticity, and that the VC protocol resulted in increased coordination and strength endurance in the functional tests, in agreement with the ultrastructural and biochemical profile. These observations support the view that VC training may be more efficient in increasing performance and may thus form the basis of training regimens when an improvement of motor efficiency is required.

Anthropometric, Cardiopulmonary and Metabolic Benefits of the High-Intensity Interval Training Versus Moderate, Low-Intensity or Control for Type 2 Diabetes: Systematic Review and Meta-Analysis

Abstract: This study aims to evaluate the effectiveness of high-intensity interval training compared with no intervention and other types of training interventions for people with Type 2 Diabetes. A systematic review and meta-analysis of randomized controlled trials that used high-interval intensity training to improve anthropometric, cardiopulmonary and metabolic conditions were conducted. The search was performed during October-December 2017 using the databases PubMed, Web of Science and Physiotherapy Evidence Database (PEDro). The methodological quality of the studies was evaluated using the PEDro scale. A total of 10 articles were included in this meta-analysis. After statistical analysis, favorable results were obtained for high-Intensity Interval Training compared with control (non-intervention): [Weight: Standardized mean difference (SMD) = -2.09; confidence interval (CI) 95%: (-3.41; -0.78); body-mass index: SMD = -3.73; CI 95%: (-5.53; -1.93); systolic blood pressure: SMD = -4.55; CI 95%: (-8.44; -0.65); VO2max: SMD = 12.20; CI 95%: (0.26; 24.14); HbA1c: SMD = -3.72; CI 95%: (-7.34; -0.10)], moderate intensity continuous training: [body-mass index: SMD = -0.41; CI 95%: (-0.80; -0.03); VO2max: SMD = 1.91; CI 95%: (0.18; 3.64)], and low intensity training: [Weight: SMD = -2.06; CI 95%: (-2.80; -1.31); body-mass index: SMD = -3.04; CI 95%: (-5.16; -0.92); systolic blood pressure: SMD = -2.17; CI 95%: (-3.93; -0.41); HbA1c: SMD = -1.58; CI 95%: (-1.84; -1.33)]. The results show that high-intensity interval training can be a useful strategy in order to improve anthropometric, cardiopulmonary and metabolic parameters in people with Type 2 diabetes. Despite this, it could be essential to clarify and unify criteria in the intervention protocols, being necessary new lines of research.

High-Intensity Interval Circuit Training Versus Moderate-Intensity Continuous Training on Functional Ability and Body Mass Index in Middle-Aged and Older Women: A Randomized Controlled Trial

The literature suggests that high-intensity interval training (HIIT) is more effective than moderate-intensity continuous training (MICT) to improve functional ability. However, there is no evidence on including HIIT in a circuit programme (HIICT). Our objective was to determine what type of training (HIICT or MICT) induces greater adaptations in the functional ability and body mass index of middle-aged and older women. The study used a quasi-experimental randomized controlled trial with 54 participants (age = 67.8 ± 6.2 years). Participants were randomly allocated to HIICT (n = 18), MICT (n = 18) or a non-exercise control group (CG; n = 18). The participants in the HIICT or MICT groups trained twice a week (1 h/session) for 18 weeks. Forty-one subjects were analysed (HIICT; n = 17, MICT; n = 12, CG; n = 12). Five subjects presented adverse events during the study. Strength, gait, cardiorespiratory fitness, balance and body mass index were measured. A significant training x group interaction was found in the arm curl test, where HIICT was statistically better than MICT and CG. Likewise, HIICT was statistically better than the CG in the BMI interaction. In lower limb strength, gait/dynamic balance and cardiorespiratory fitness, both HIICT and MICT were statistically better than the CG. In conclusion, HIICT generated better adaptations in upper limb strength than MICT. Likewise, HIICT generated better adaptations in body mass index than CG. Finally, both HIICT and MICT had a similar influence on strength, cardiorespiratory fitness and gait/dynamic balance.

Respiratory training interventions improve health status of heart failure patients: A systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Prior studies indicate that doing breathing exercises improves physical performance and quality of life (QoL) in heart failure patients. However, these effects remain unclear and contradictory.

AIM

To determine the effects of machine-assisted and non-machine-assisted respiratory training on physical performance and QoL in heart failure patients.

METHODS

This was a systematic review and network meta-analysis study. A literature search of electronic databases was conducted for randomized controlled trials (RCTs) on heart failure. Respiratory training interventions were grouped as seven categories: IMT_Pn (inspiratory muscle training without pressure or < 10% maximal inspiratory pressure, MIP), IMT_Pl (inspiratory muscle training with low pressure, 10%-15% MIP), IMT_Pm (inspiratory muscle training with medium pressure, 30%-40% MIP), IMT_Ph (inspiratory muscle training with high pressure, 60% MIP or MIP plus aerobics), Aerobics (aerobic exercise or weight training), Qi_Ex (tai chi, yoga, and breathing exercise), and none. The four outcomes were heart rate, peak oxygen uptake (VO₂ peak), 6-min walking distance test (6MWT), and Minnesota Living with Heart Failure QoL. The random-effects model, side-splitting model, and the surface under the cumulative ranking curve (SUCRA) were used to test and analyze the data.

RESULTS

A total of 1499 subjects from 31 RCT studies were included. IMT_Ph had the highest effect sizes for VO₂ peak and 6MWT, IMT_Pm highest for QoL, and Qi_Ex highest for heart rate. Aerobics had the second highest for VO₂ peak, Qi_Ex second highest for 6MWT, and IMT_Ph second highest for heart rate and QoL.

CONCLUSION

This study supports that high- and medium-intensity machine-assisted training improves exercise capacity and QoL in hospital-based heart failure patients. After hospital discharge, non-machine-assisted training continuously improves cardiac function.