HIIT vs Moderate Training Tested in Phase III Cardiac Rehab Patients
A completed trial of 69 coronary artery disease patients compares HIIT and moderate continuous training on fitness, activity, and quality of life.
Summary
This completed clinical trial from the University of Évora enrolled 69 patients with coronary artery disease to compare high-intensity interval training (HIIT) against moderate-intensity continuous training (MICT) in a phase III cardiac rehabilitation setting. Researchers examined how each exercise approach affected cardiovascular fitness, informal physical activity habits, sedentary behavior, and quality of life. The study was conducted in the Alentejo region of Portugal, an area previously lacking formal cardiac rehabilitation coverage. Phase III rehabilitation focuses on long-term maintenance after initial hospital-based care, making exercise modality choice particularly important for sustained outcomes. The trial ran from late 2018 through mid-2023, providing a robust follow-up window to assess real-world adherence and health impacts in this older, higher-risk population.
Detailed Summary
Cardiovascular disease remains the leading driver of mortality and disability worldwide, and its burden grows heavier as populations age. In Portugal's Alentejo region, the absence of structured cardiac rehabilitation programs created an urgent public health gap — one this trial was designed to address while simultaneously answering a key scientific question: which exercise approach delivers better outcomes for cardiac patients in long-term rehab?
This randomized clinical trial enrolled 69 patients diagnosed with coronary artery disease and assigned them to either a high-intensity interval training (HIIT) program or a moderate-intensity continuous training (MICT) program during phase III cardiac rehabilitation — the community-based maintenance phase that follows early hospital and outpatient recovery. Researchers tracked cardiovascular fitness, self-reported informal physical activity, sedentary time, and quality of life across both groups over a multi-year follow-up period ending in June 2023.
Prior research has generally favored HIIT for producing greater gains in aerobic capacity and reversing cardiac deconditioning compared to traditional moderate continuous exercise. This trial aimed to test whether those advantages hold in a real-world phase III setting, where patient adherence, aging-related comorbidities, and unsupervised activity all complicate outcomes.
The implications are clinically meaningful. If HIIT proves superior or equivalent in safety and efficacy during long-term maintenance rehab, it could reshape exercise prescription guidelines for cardiac patients — particularly in resource-limited regions where maximizing benefit per session matters most.
However, because only the abstract is publicly available, specific outcome data, effect sizes, adverse event rates, and statistical findings cannot be reported here. The trial's single-region recruitment in a population with no prior CR exposure may also limit generalizability to other healthcare contexts. Full publication of results is needed to draw definitive conclusions.
Key Findings
- Trial directly compared HIIT and MICT in phase III cardiac rehab — a real-world long-term maintenance setting rarely studied.
- Both sedentary behavior and informal physical activity were tracked, capturing lifestyle impact beyond supervised exercise sessions.
- Study addressed a genuine public health gap: Alentejo region had no prior cardiac rehabilitation coverage before this program.
- 69 coronary artery disease patients enrolled with a multi-year follow-up through June 2023, allowing longer-term outcome assessment.
- Quality of life was included as a primary outcome, recognizing that patient wellbeing extends beyond cardiovascular fitness metrics.
Methodology
This was a completed interventional clinical trial (Phase NA) randomizing 69 coronary artery disease patients to HIIT or MICT during phase III cardiac rehabilitation. Outcomes included cardiovascular fitness, informal physical activity levels, sedentary behavior, and quality of life. The trial ran from December 2018 to June 2023, sponsored by the University of Évora, Portugal.
Study Limitations
This summary is based on the abstract only, as the full study results are not publicly accessible; specific outcomes, effect sizes, and safety data cannot be reported. The study recruited exclusively from a single underserved Portuguese region, which may limit generalizability to other populations or healthcare systems. The non-blinded nature typical of exercise intervention trials introduces potential performance and reporting bias.
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