# Effect of home-based high-intensity interval training versus moderate-intensity continuous training in patients with myocardial infarction: a randomized controlled trial PMID: 34993836 Journal: Irish journal of medical science Published: 2022-12-01 Authors: Yakut H, Dursun H, Felekoğlu E, Başkurt AA, Alpaydın AÖ, Özalevli S ## Question What are the effects of home-based HIIT compared with home-based moderate-intensity continuous training in patients with myocardial infarction? ## Summary This randomized trial compared two home-based exercise programs in stable myocardial infarction patients. Twice-weekly 12-week home HIIT and moderate continuous walking both improved 6-minute walk distance, blood pressure, resting heart rate, oxygen saturation, pulmonary function, respiratory and peripheral muscle strength, body composition, and quality of life measures. HIIT produced greater improvements than MICT in several pulmonary-function measures and knee extensor strength. The authors reported no adverse events during either intervention. ## Population - Clinically stable myocardial infarction patients, 3 months to 1 year post-MI, age 35-65, LVEF >50%, able to walk independently. - Sample size: 21 - Age: HIIT 59.6 +/- 4.5 years; MICT 58.5 +/- 5.6 years. - Sex: HIIT 10 male/1 female; MICT 8 male/2 female. - Fitness level: Post-MI outpatient rehabilitation population; baseline 6MWT about 492-509 m. - Health status: Stable post-MI with preserved LVEF; hypertension, diabetes, and chronic pulmonary disease were present in some participants. ## Methodology - Randomized controlled trial with two parallel home-based exercise groups. - 12 weeks. - Outpatients cardiopulmonary rehabilitation clinic for baseline/post testing, with exercise performed at home after initial instruction. - Randomized and controlled study design. ## Protocol - Home-based HIIT. - Modality: Walking uphill, brisk walking, jogging, crouching, and going up/down front-side steps in the home environment. - Work intervals: 4 minutes. - Recovery: 3 minutes active recovery walking. - Sets or repetitions: Four intervals. - Intensity: 85-95% HR reserve and RPE 15-18 for work intervals; recovery at 70% HR reserve and RPE <14. - Session duration: Approximately 48 minutes including 10-minute warm-up, 28-minute interval block, and 10-minute cool-down. - Frequency: 2 sessions/week on non-consecutive days. - Program length: 12 weeks. - Progression: Lower intensity/time in first 2 weeks, then intensity and duration increased every 2 weeks. - Home-based moderate-intensity continuous training. - Modality: Walking. - Work intervals: Continuous walking for 20-45 minutes. - Sets or repetitions: One continuous bout. - Intensity: 70-75% HR reserve and RPE 12-14. - Session duration: Approximately 40-65 minutes including 10-minute warm-up, 20-45 minutes MICT, and 10-minute cool-down. - Frequency: 2 sessions/week on non-consecutive days. - Program length: 12 weeks. - Progression: Lower intensity/time in first 2 weeks, then intensity and duration increased every 2 weeks. ## Outcomes ### 6-minute walk distance Status: improved Both HIIT and MICT significantly improved 6MWT distance, with no significant between-group difference. HIIT 509.0 +/- 59.8 to 549.4 +/- 62.3 m, p=0.013; MICT 491.9 +/- 79.7 to 517.4 +/- 82.1 m, p=0.015; change difference p=0.386. ### Blood pressure and resting heart rate Status: improved Both groups decreased resting systolic and diastolic BP and resting HR. Between-group changes were not significant: SBP p=0.782, DBP p=0.435, HR p=0.731. ### Pulmonary function Status: improved Both groups improved pulmonary function, and HIIT improved FEV1, FVC, and PEF more than MICT. Between-group change p values: FEV1% predicted p=0.034, FVC% predicted p=0.002, PEF% predicted p=0.043. ### Body composition Status: improved BMI and body fat percentage decreased in both groups; fat-free mass did not significantly change. Between-group changes were not significant for BMI p=0.776 and body fat percentage p=0.287. ### Peripheral muscle strength Status: improved Knee extensor and handgrip strength increased in both groups; knee extensor strength improved more in HIIT. Knee extensor strength change HIIT +4.4 +/- 2.1 kg vs MICT +1.0 +/- 0.6 kg, between-group p<0.001; handgrip change p=0.070. ### Health-related quality of life Status: improved HIIT improved physical, emotional, social, and global MacNew scores; MICT improved global score only; between-group changes were not significant. MacNew global p=0.008 within HIIT and p<0.012 within MICT; between-group global change p=0.660. ### Safety Status: no clear change No adverse events occurred during either exercise intervention. ## Practical Insights - A home 4x4 HIIT format can be delivered with walking/step-based modalities when patients are screened, instructed, and monitored remotely. - For functional capacity after MI, home HIIT did not outperform home MICT in 6MWT change, so HIIT claims should be outcome-specific. - Combining HR reserve and RPE targets is a practical way to guide home intensity. ## Limitations - Small sample size. - No no-exercise control group. - Home exercise execution was not monitored in real time. - Per-protocol analysis limits interpretation of adherence and effectiveness. ## Safety And Adherence - No adverse events occurred during the exercise intervention in both groups. - Patients received initial instruction on HR monitoring and target HR. - Weekly phone counseling assessed problems related to exercise. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/34993836/) (pubmed) - [DOI](https://doi.org/10.1007/s11845-021-02867-x) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8736320/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.