Low-Volume High-Intensity Aerobic Interval Training Is an Efficient Method to Improve Cardiorespiratory Fitness After Myocardial Infarction: PILOT STUDY FROM THE INTERFARCT PROJECT

Impact of Aerobic High-Intensity Interval Training Intervention and Mediterranean Diet Recommendations on Health-Related Quality of Life and Lifestyle Modification in Post-Myocardial Infarction Patients: Results From the INTERFARCT Surveys

This study aims to determine the impact of 2 (low vs high volume) high-intensity interval training (HIIT) programs with Mediterranean diet (MedDiet) recommendations on health-related quality of life (HRQoL) and lifestyle modification, and to examine the relationships between the changes in anxiety and depression with HRQoL and lifestyle variables after myocardial infarction (MI). Participants (n = 80) were randomized to attention control or one of the two supervised HIIT groups (2 d/weeks). Surveys before and after intervention (16 weeks): HRQoL (SF-36), anxiety and depression (HADS), MedDiet adherence (MEDAS), and physical activity (PA) and sedentary behavior (SB) levels. After intervention, there were improvements (P < .05) in HRQoL, HADS scores, and MedDiet adherence, with higher PA level in both HIIT groups with no between-HIIT group differences. The HADS score decline correlated (P < .05) with both the increase in physical component of SF-36 (r = .42), the overall metabolic expenditure (r = .26), and adherence to the MedDiet (r = .24), and the reduction in the SB (r = .35). HIIT exercise intervention with MedDiet recommendations improved HRQoL, along with reduced anxiety and depression symptoms, and a healthier lifestyle after MI. Better mental health was related to higher values of PA and MedDiet adherence.

Nutritional Aspects to Cardiovascular Diseases and Type 2 Diabetes Mellitus

PURPOSE OF REVIEW

In this narrative review, we discuss the current evidence related to the role of dietary interventions to prevent and treat type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). We also propose alternative therapeutic strategies other than weight loss in this population, namely, improvements in cardiorespiratory fitness and its determinants.

RECENT FINDINGS

While weight loss has been consistently associated with the prevention of T2DM and improvements in glycemic control in those with established diseases, its role in preventing and treating CVD is less clear. In fact, in this setting, improvements in diet quality have provided greater benefits, suggesting that this might represent an alternative, or an even more effective strategy than energy-restriction. Improvements in diet quality, with and without caloric restriction have been shown to improve CVD risk and to prevent the development of T2DM in individuals at risk; however, with regard to glycemic control in patients with T2DM, any dietary intervention resulting in significant weight loss may produce clinically meaningful benefits. Finally, dietary interventions with and without energy restriction that can improve cardiorespiratory fitness, even in absence of weight loss in patients with obesity, should be encouraged.

High-intensity interval training in patients with intermittent claudication

OBJECTIVE

Provision, uptake, adherence, and completion rates for supervised exercise programs (SEP) for intermittent claudication (IC) are low. A shorter, more time-efficient, 6-week, high-intensity interval training (HIIT) program may be an effective alternative that is more acceptable to patients and easier to deliver. The aim of this study was to determine the feasibility of HIIT for patients with IC.

METHODS

A single arm proof-of-concept study, performed in secondary care, recruiting patients with IC referred to usual-care SEPs. Supervised HIIT was performed three times per week for 6 weeks. The primary outcome was feasibility and tolerability. Potential efficacy and potential safety were considered, and an integrated qualitative study was undertaken to consider acceptability.

RESULTS

A total of 280 patients were screened: 165 (59%) were eligible, and 40 (25%) were recruited. The majority (n = 31; 78%) of participants completed the HIIT program. The remaining nine patients were withdrawn or chose to withdraw. Completers attended 99% of training sessions, completed 85% of sessions in full, and performed 84% of completed intervals at the required intensity. There were no related serious adverse events. Maximum walking distance (+94 m; 95% confidence interval, 66.6-120.8 m) and the SF-36 physical component summary (+2.2; 95% confidence interval, 0.3-4.1) were improved following completion of the program.

CONCLUSIONS

Uptake to HIIT was comparable to SEPs in patients with IC, but completion rates were higher. HIIT appears feasible, tolerable, and potentially safe and beneficial for patients with IC. It may provide a more readily deliverable, acceptable form of SEP. Research comparing HIIT with usual-care SEPs appears warranted.

The effect of low volume high-intensity interval training on metabolic and cardiorespiratory outcomes in patients with type 2 diabetes mellitus: A systematic review and meta-analysis

Aims

The present systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to investigate the effect of low volume high-intensity interval training (LVHIIT) on the metabolic and cardiorespiratory outcomes in patients with type 2 diabetes mellitus (T2DM).

Methods

Relevant articles were sourced from PubMed, EBSCO, Web of Science, Embase, and the Cochrane Library from inception to October 2022. The study search strategy and all other processes were implemented in accordance with the PRISMA statement.

Results

Five randomized controlled trials that satisfied the inclusion criteria were included in this meta-analysis. The LVHIIT group had significantly lower fasting blood glucose levels (RR= -1.21; 95% CI= -2.02- -0.40, p = 0.0032) and HbA1c levels (RR= -0.65; 95% CI= -1.06- -0.23, p = 0.002) and higher levels of insulin resistance indicator HOMA-IR (RR= -1.34; 95% CI = -2.59- -0.10, p = 0.03) than the control group. Moreover, our results show that LVHIIT can reduce body mass (RR = -0.94, 95% CI = -1.37- -0.51, p<0.0001) and body mass index (RR = -0.31, 95% CI = -0.47- -0.16, p<0.0001). LVHIIT had a better therapeutic effect on blood lipid metabolism, such as total cholesterol, high-density lipoprotein, low-density lipoprotein and triglycerides. However, the change in fasting insulin levels was not statistically significant (RR= -1.43; 95% CI = -3.46- 0.60, p =0.17). Furthermore, LVHIIT reduced the systolic blood pressure (RR =-4.01, 95% CI = -4.82 - -3.21, p<0.0001) and improved peak oxygen uptake (VO2peak) compared to the control group (RR= 5.45; 95% CI = 1.38 - 9.52, p =0.009).

Conclusion

After a certain period of LVHIIT, glycaemic control, insulin resistance, body weight, lipid profile and cardiorespiratory outcomes were significantly improved in T2DM patients.

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.

Mechanisms of Exercise Capacity Improvement after Cardiac Rehabilitation Following Myocardial Infarction Assessed with Combined Stress Echocardiography and Cardiopulmonary Exercise Testing

Cardiac rehabilitation (CR) is indicated in all patients after acute myocardial infarction (AMI) to improve prognosis and exercise capacity (EC). Previous studies reported that up to a third of patients did not improve their EC after CR (non-responders). Our aim was to assess the cardiac and peripheral mechanisms of EC improvement after CR using combined exercise echocardiography and cardiopulmonary exercise testing (CPET-SE). The responders included patients with an improved EC assessed as a rise in peak oxygen uptake (VO₂) ≥ 1 mL/kg/min. Peripheral oxygen extraction was calculated as arteriovenous oxygen difference (A-VO₂Diff). Out of 41 patients (67% male, mean age 57.5 ± 10 years) after AMI with left ventricular ejection fraction (LVEF) ≥ 40%, 73% improved their EC. In responders, peak VO₂ improved by 27% from 17.9 ± 5.2 mL/kg/min to 22.7 ± 5.1 mL/kg/min, p < 0.001, while non-responders had a non-significant 5% decrease in peak VO₂. In the responder group, the peak exercise heart rate, early diastolic myocardial velocity at peak exercise, LVEF at rest and at peak exercise, and A-VO₂Diff at peak exercise increased, the minute ventilation to carbon dioxide production slope decreased, but the stroke volume and cardiac index were unchanged after CR. Non-responders had no changes in assessed parameters. EC improvement after CR of patients with preserved LVEF after AMI is associated with an increased heart rate response and better peripheral oxygen extraction during exercise.

Exercise-Based Interventions in Middle-Aged and Older Adults after Myocardial Infarction: A Systematic Review

This study summarized the relevant literature and aimed to determine the effect of exercise-based interventions after myocardial infarction in middle-aged and older adults. Studies were identified and analyzed according to the PRISMA guidelines. The following electronic databases were used: Google Scholar, PubMed, Mendeley, Science Direct, and Scopus. The identified studies had to be longitudinal, be published in English, have taken place between 2010 and 2020, involve participants who had suffered myocardial infarction, and address different types of exercise-based interventions to be included. Of the 592 relevant studies identified, 20 were included in the qualitative analysis. After analyzing the results obtained, it could be concluded that different types of exercise-based interventions or their combination have a positive effect after myocardial infarction in middle-aged and elderly adults. It can also be suggested that the combination of a cycle ergometer and a treadmill may be the most effective exercise-based intervention. An adequate choice of intensity and volume is crucial, with the optimal duration of the experimental program and the type(s) of exercises adapted to participants after myocardial infarction.

The effect of high-intensity interval training on exercise capacity in post-myocardial infarction patients: a systematic review and meta-analysis

AIMS

Exercise-based cardiac rehabilitation has been recommended a treatment for patients with cardiovascular disease. Nevertheless, it remains controversial which exercise characteristics are most beneficial for post-myocardial infarction (MI) patients. We performed a systematic review and meta-analysis to investigate the effects of high-intensity interval training (HIIT) in these patients.

METHODS AND RESULTS

We searched PubMed, Embase, the Cochrane Library, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP), and Wanfang Dataset (from the earliest date available to February 2021) for randomized controlled trials and cohort studies that evaluated the effects of HIIT on post-MI patients. Studies were selected according to inclusion and exclusion criteria. Data synthesis was performed with R software version 4.0.1. Eight studies met the study criteria, including 387 patients. Compared to the control group [moderate-intensity continuous training (MICT) and/or routine physical activity], HIIT significantly improved peak oxygen uptake (peak VO2) [mean difference = 3.83 mL/kg/min, 95% confidence interval (CI) (3.25, 4.41), P < 0.01]. No significant difference in systolic and diastolic blood pressures, peak and resting heart rate, left ventricular ejection fraction, left ventricular end-diastolic volume, and the quality of life was found between HIIT group and control group. The duration of follow-up ranged from 6 to 12 weeks. The incidence of adverse events was similar between groups [risk difference = 0.01, 95% CI (-0.02, 0.04), P = 0.53].

CONCLUSION

Compared with MICT and routine physical activity, HIIT could significantly improve exercise capacity in post-MI patients, and appears to be safe.

Chronotropic Responses to Exercise and Recovery in Myocardial Infarction Patients Taking β-Blockers Following Aerobic High-Intensity Interval Training: AN INTERFARCT STUDY

PURPOSE

The objectives of this study were to compare the effects of two different high-intensity interval training (HIIT) programs (low-volume vs high-volume) on chronotropic responses during exercise and recovery, and to contrast the results of the HIIT groups together to only physical activity recommendations in post-myocardial infarction (MI) patients taking β-blockers.

METHODS

Resting heart rate (HRrest), peak HR (HRpeak), HR reserve (HRreserve = HRpeak-HRrest), HR recovery (HRR) as the difference between HRpeak and post-exercise HR, and chronotropic incompetence were assessed in 70 patients (58 ± 8 yr) following MI with a cardiopulmonary exercise test to peak exertion before and after a 16-wk exercise intervention period. All participants were randomized to either attention control (AC) (physical activity recommendations) or one of the two supervised HIIT groups (2 d/wk).

RESULTS

After the intervention, no significant between-HIIT group differences were observed. The HRpeak increased (P < .05) in low- (Δ= 8 ± 18%) and high-volume HIIT (Δ= 6 ± 9%), with a small decrease in AC (Δ=- 2 ± 12%, P > .05) resulting in large differences (P < .05) between HIIT and AC. The HRreserve increased (P < .05) in high-volume HIIT. The HRR slightly increased (P < .05) in low-volume (5th min, Δ= 19 ± 31%) and high-volume HIIT (2nd min, Δ= 15 ± 29%, and 5th min, Δ= 19 ± 28%).

CONCLUSION

These findings suggest that both low- and high-volume HIIT elicit similar improvements in chronotropic responses after MI, independent of β-blocker treatment. Supervised HIIT was more effective than giving physical activity recommendations alone. Low-volume HIIT is presented as a potent and time-efficient exercise strategy that could enhance the sympathovagal balance in this population.

Adherence to High-Intensity Interval Training in Cardiac Rehabilitation: A REVIEW AND RECOMMENDATIONS

PURPOSE

High-intensity interval training (HIIT) is gaining popularity as a training approach for patients attending cardiac rehabilitation (CR). While the literature has focused on the efficacy of HIIT for improving cardiorespiratory fitness (CRF), particularly when compared with moderate intensity exercise, less emphasis has been placed on adherence to HIIT. The aim of this review was to summarize the current literature regarding adherence to HIIT in CR patients with coronary artery disease.

REVIEW METHODS

A review identified 36 studies investigating HIIT in CR patients with coronary artery disease. Methods and data were extracted for exercise or training adherence (to attendance, intensity, and duration), feasibility of protocols, and CRF. The review summarizes reporting of adherence; adherence to HIIT and comparator/s; the influence of adherence on changes in CRF; and feasibility of HIIT.

SUMMARY

Adherence to the attendance of HIIT sessions was high and comparable with moderate-intensity exercise. However, adherence to the intensity and duration of HIIT was variable and underreported, which has implications for determining the treatment effect of the exercise interventions being compared. Furthermore, additional research is needed to investigate the utility of home-based HIIT and long-term adherence to HIIT following supervised programs. This review provides recommendations for researchers in the measurement and reporting of adherence to HIIT and other exercise interventions to facilitate a sufficient and consistent approach for future studies. This article also highlights strategies for clinicians to improve adherence, feasibility, and enjoyment of HIIT for their patients.

Sex Differences in Cardiometabolic Health Indicators after HIIT in Patients with Coronary Artery Disease

PURPOSE

Cardiorespiratory fitness (CRF) is an independent predictor of mortality, and females typically achieve smaller improvements in CRF than males after exercise-based cardiac rehabilitation. High-intensity interval training (HIIT) has been shown to produce superior improvements in CRF than traditional cardiac rehabilitation, but the sex differences are unknown. The purpose of this systematic review and meta-analysis was to evaluate sex differences for changes in CRF and cardiometabolic health indicators after HIIT in adults with coronary artery disease (CAD).

METHODS AND RESULTS

A systemic search of five electronic databases for studies examining the effect of HIIT on measured CRF and cardiometabolic health indicators in adults with CAD was performed. Data (published and unpublished) from 14 studies were included in the meta-analyses with approximately eightfold greater male than female participation (n = 836 vs n = 103). Males with CAD achieved a near-significant absolute improvement in CRF (mean difference [MD] = 1.07, 95% confidence interval [CI] = -0.08 to 2.23 mL·kg-1⋅min-1, P = 0.07) after HIIT when compared with control; there were insufficient data to conduct such an analysis in females. Significantly smaller improvements in CRF were experienced by females than males (MD = -1.10, 95% CI = -2.08 to -0.12 mL·kg-1⋅min-1, P = 0.03); there was no sex difference for the relative (percentage) change in CRF after HIIT. Females achieved significantly smaller reductions in body mass index (MD = -0.25, 95% CI = -0.03 to -0.47 kg·m-2, P = 0.02) and fasting blood glucose (MD = -0.38, 95% CI = -0.05 to -0.72, P = 0.03); no sex differences were observed for other cardiometabolic health indicators.

CONCLUSION

There are no sex differences for relative improvements in CRF after HIIT; however, females are greatly underrepresented in trials. Future studies should increase female participation and perform sex-based analyses to determine sex-specific outcomes following HIIT.

Considering the Feasibility, Tolerability, and Safety of High-Intensity Interval Training as a Novel Treatment for Patients With Intermittent Claudication

PURPOSE

This study assessed the feasibility, tolerability, safety, and potential efficacy of a novel, 6-wk, high-intensity interval training (HIIT) program for patients with intermittent claudication (IC).

METHODS

Patients referred to a usual-care supervised exercise program were invited to undertake a HIIT program. All recruited patients performed a baseline cardiopulmonary exercise test (CPX) to inform their exercise prescription. HIIT involved 10, 1-min high-intensity cycling intervals interspersed with 1-min recovery intervals, performed 3 d/wk for 6 wk. Outcomes included feasibility, tolerability, safety, walking distance, and quality of life.

RESULTS

A total of 144 patients with IC were referred, 95 met initial eligibility criteria (66%) and 30 (32%) were recruited for HIIT, of which 15 (50%) completed. Of the recruited patients, 90% were on optimal medical therapy and 40% had concomitant cardiac, cerebrovascular, and/or respiratory disease. Patients who completed the program attended 100% of the sessions and one serious adverse event was recorded. Improvements in walking distances and quality of life were observed. Following recruitment of the first 20 patients, the inclusion criteria were refined on the basis of CPX, leading to improved completion rates.

CONCLUSIONS

This study provides preliminary findings indicating that patients with IC can complete a short-term HIIT program. We provide very early evidence that HIIT may be safe and well-tolerated. In addition, walking distances seem to improve following HIIT. After a small change in the exclusion criteria, the intervention and inclusion/exclusion criteria now seem appropriate for this population, meaning further research to evaluate HIIT in patients with IC is warranted.

Are the Current Cardiac Rehabilitation Programs Optimized to Improve Cardiorespiratory Fitness in Patients? A Meta-Analysis

Previous meta-analyses have shown that high-intensity interval training (HIIT) is more suitable than moderate continuous training (MCT) for improving peak oxygen uptake (VO2peak) in patients with coronary artery disease. However, none of these meta-analyses have tried to explain the heterogeneity of the empirical studies in optimizing cardiac rehabilitation programs. Therefore, our aims were (a) to estimate the effect of MCT and HIIT on VO2peak, and (b) to find the potential moderator variables. A search was conducted in PubMed, Scopus, and ScienceDirect. Out of the 3,110 references retrieved, 29 studies fulfilled the selection criteria to be included in our meta-analysis. The mean difference was used as the effect size index. Our results showed significant enhancements in VO2peak after cardiac rehabilitation based on MCT and HIIT (mean difference = 3.23; 95% confidence interval [2.81, 3.65] ml·kg-1·min-1 and mean difference = 4.61; 95% confidence interval [4.02, 5.19] ml·kg-1·min-1, respectively), with greater increases after HIIT (p < .001). Heterogeneity analyses reached statistical significance with moderate heterogeneity for MCT (p < .001; I2 = 67.0%), whereas no heterogeneity was found for the effect of HIIT (p = .220; I2 = 22.0%). Subgroup analyses showed significant between-group heterogeneity of the MCT-induced effect based on the training mode (p < .001; I2 = 90.4%), the risk of a new event (p = .010; I2 = 77.4%), the type of cardiovascular event (p = .009; I2 = 84.8%), the wait time to start cardiac rehabilitation (p = .010; I2 = 76.6%), and participant allocation (p = .002; I2 = 89.9%). Meta-regressions revealed that the percentages of patients undergoing a revascularization procedure (B = -0.022; p = .041) and cardiorespiratory fitness at baseline (B = -0.103; p = .025) were inversely related to the MCT-induced effect on the VO2peak.

Response to Exercise Training During Cardiac Rehabilitation Differs by Sex

PURPOSE

Directly measured peak aerobic capacity or oxygen uptake is a powerful predictor of prognosis in individuals with cardiovascular disease. Women enter phase 2 cardiac rehabilitation (CR) with lower and their response to training, compared with men, is equivocal. We analyzed at entry and exit in patients participating in CR and improvements by diagnosis to assess training response. We also identified sex differences that may influence change in .

METHODS

The cohort included consecutive patients enrolled in CR between January 1996 and December 2015 who performed entry exercise tolerance tests. Data collected included demographics, index diagnosis, , and exercise training response.

RESULTS

The cohort consisted of 3925 patients (24% female). There was a significant interaction between baseline and diagnosis (P < .001), with percutaneous coronary intervention and myocardial infarction greater than other diagnoses. Surgical patients demonstrated greater improvement in than nonsurgical diagnoses (n = 1789; P < .001). Women had lower than men for all diagnoses (P < .02) and demonstrated less improvement (13 vs 17%, P < .001). Percent improvement using estimated metabolic equivalents of task (METs) were similar for women and men (33 vs 31%, P = NS). Despite overall increases in , 18% of patients (24% women, 16% men) failed to demonstrate any improvement (exit ≤ entry ).

CONCLUSIONS

While there were no differences in training effect estimated by METs, directly measured showed a significantly lower training response for women despite adjusting for covariates. In addition, 18% of patients did not see any improvement in . Alternatives to traditional CR exercise programming need to be considered.