High-intensity interval training versus moderate-intensity continuous training within cardiac rehabilitation: a systematic review and meta-analysis

Abstract

Background: Aerobic capacity has been shown to be inversely proportionate to cardiovascular mortality and morbidity and there is growing evidence that high-intensity interval training (HIIT) appears to be more effective than moderate-intensity continuous training (MICT) in improving cardiorespiratory fitness within the cardiac population. Previously published systematic reviews in cardiovascular disease have neither investigated the effect that the number of weeks of intervention has on cardiorespiratory fitness changes, nor have adverse events been collated. Objective: We aimed to undertake a systematic review and meta-analysis of randomized controlled trials (RCTs) within the cardiac population that investigated cardiorespiratory fitness changes resulting from HIIT versus MICT and to collate adverse events. Methods: A critical narrative synthesis and meta-analysis was conducted after systematically searching relevant databases up to July 2017. We searched for RCTs that compared cardiorespiratory fitness changes resulting from HIIT versus MICT interventions within the cardiac population. Results: Seventeen studies, involving 953 participants (465 for HIIT and 488 for MICT) were included in the analysis. HIIT was significantly superior to MICT in improving cardiorespiratory fitness overall (SMD 0.34 mL/kg/min; 95% confidence interval [CI; 0.2-0.48]; p<0.00001; I 2 =28%). There were no deaths or cardiac events requiring hospitalization reported in any study during training. Overall, there were more adverse events reported as a result of the MICT (n=14) intervention than the HIIT intervention (n=9). However, some adverse events (n=5) were not classified by intervention group. Conclusion: HIIT is superior to MICT in improving cardiorespiratory fitness in participants of cardiac rehabilitation (CR). Improvements in cardiorespiratory fitness are significant for CR programs of >6-week duration. Programs of 7-12 weeks' duration resulted in the largest improvements in cardiorespiratory fitness for patients with coronary artery disease. HIIT appears to be as safe as MICT for CR participants.

The impact of high‐intensity interval training on ventricular remodeling in patients with a recent acute myocardial infarction—A randomized training intervention pilot study

“…However, in our study only patients in the HIIT group showed a substantial improvement and reached a normal age‐predicted after completion of the program with the identical level of exhaustion (ie, RER) as compared to the usual care group. This improvement is consistent with existing data in the identical population and with the biggest and latest of numerous meta‐analyses comparing HIIT and MICET in a population of CHD patients who reported the most pronounced improvements with HIIT after 7 to 12 weeks of training . The finding that at the VT1 improved only in the HIIT group indicates an improvement in muscular function as a result of structured exercise training and is plausible …”

“…MICET in a population of CHD patients who reported the most pronounced improvements with HIIT after 7 to 12 weeks of training. 16,32 The finding that _ VO 2 at the VT1 improved only in the HIIT group indicates an improvement in muscular function as a result of structured exercise training and is plausible. 33 LVEF, left ventricular ejection fraction; LVEDVi, left ventricular end-diastolic volume index; LVMI, left ventricular mass index; SR, strain rate; Peak A, peak late mitral inflow velocity; Peak E, peak early mitral inflow velocity; TDI-e 0 lateral, tissue Doppler imaging-derived peak early diastolic lateral mitral annulus velocity; TDI-e 0 septal, tissue Doppler imaging-derived peak early diastolic septal mitral annulus velocity; E/e 0 , peak early mitral inflow velocity to peak early diastolic mitral annulus velocity ratio.…”

“…Furthermore, aerobic exercise training has been shown to be associated with a lowering of GRK2 expression and to predict outcomes in patients with chronic ischemic heart failure in a prospective study . High‐intensity interval training (HIIT) is more effective at improving and can be performed safely compared to the more established moderate‐intensity continuous exercise training (MICET) in stable CHD patients …”

“…13 Highintensity interval training (HIIT) is more effective at improving _ VO 2peak and can be performed safely compared to the more established moderate-intensity continuous exercise training (MICET) in stable CHD patients. [14][15][16] However, most prior studies included predominantly stable patients. To the best of our knowledge, the effect of HIIT on cardiac remodeling including advanced echocardiography (ie, myocardial strain imaging) and GRK2 expression has not yet been studied in patients with a recent AMI.…”

Effectiveness of High‐Intensity Interval Training for Fitness and Mobility Post Stroke: A Systematic Review

“…Due to underlying medical comorbidities and functional limitations of individuals post stroke, task performance safety in terms of physical and physiological events may be a concern during HIIT. However, it has been shown that HIIT is a safe and effective intervention in a variety of clinical populations, including those with cardiovascular and respiratory diseases …”