Comparable Improvements in Heart Rate Recovery Following Short-Term High-Intensity and Moderate-Intensity Interval Training in Patients with Cardiovascular Disease
Question
Do 4 weeks of supervised high-intensity interval training and moderate-intensity interval training improve heart rate recovery and cardiopulmonary function in patients with cardiovascular disease, and are their effects comparable?
Summary
This retrospective cohort study compared 4 weeks of supervised cycling HIIT with moderate-intensity interval training in 209 cardiovascular disease patients in cardiac rehabilitation. Both programs improved 1-minute heart rate recovery, resting heart rate, peak oxygen uptake, exercise time, workload, blood pressure, anxiety and depression scores, and waist circumference. Improvements in heart rate recovery were similar between HIIT and MIIT.
Methodology
- Cardiovascular disease patients completing supervised outpatient cardiac rehabilitation in China.
- 209 participants.
- Cycling.
- Work intervals: 30 seconds at 80-90% maximal work rate, RPE 14-15.
- Recovery: 30 seconds low-intensity recovery.
- Intensity: 80-90% WR; RPE 14-15.
- Approximately 40-45 minutes including cool-down.
- 3 sessions per week.
- 4 weeks, 12 sessions.
- Retrospective cohort study comparing nonrandomized HIIT and MIIT groups from routine cardiac rehabilitation records.
- Heart rate recovery, Peak oxygen uptake, Resting heart rate, and Blood pressure were tracked.
Outcomes
Heart rate recovery
Both HIIT and MIIT significantly improved HRR, with no significant between-group difference.
HIIT +3.1 +/- 8.7 bpm, P=0.002; MIIT +3.0 +/- 10.0 bpm, P=0.001; between-group P=0.816.
Peak VO2
Peak VO2 increased significantly in both groups without a significant between-group difference.
HIIT +3.3 +/- 2.8 mL/kg/min; MIIT +3.0 +/- 3.6 mL/kg/min; both P<0.001; between-group P=0.122.
AT VO2
AT VO2 improved in both groups, with a larger improvement in the HIIT group.
HIIT +1.9 +/- 2.3 mL/kg/min; MIIT +1.3 +/- 2.5 mL/kg/min; both P<0.001; between-group P=0.010.
Resting heart rate
Resting HR decreased significantly in both groups and was the consistent independent predictor of HRR improvement.
HIIT -7.0 +/- 12.9 bpm, P<0.001; MIIT -4.6 +/- 13.8 bpm, P<0.001; resting HR change beta -0.227 in HIIT (P=0.040), -0.318 in MIIT (P<0.001), and -0.286 overall (P<0.001).
Safety during training
No adverse cardiovascular events occurred during training in either group.
Examples listed by authors included angina or syncope; no event counts beyond zero were reported.
Insights
- A short 4-week supervised 30:30 cycling HIIT program can improve HRR and peak VO2 in cardiac rehabilitation completers.
- Moderate-intensity interval training may deliver similar HRR gains for patients with cardiovascular disease who may not tolerate HIIT.
- Clinical translation depends on risk stratification, CPET-based prescription, and supervised monitoring.
Limitations
- Retrospective design.
- Nonrandomized group assignment and potential selection bias.
- Single-center study.
- Short 4-week intervention.
- No long-term follow-up for HRR durability or clinical outcomes.
- Autonomic function assessed only through HRR.
- Only completers with pre/post CPET were included.
- Wide age range and variable disease severity may confound results.
Safety
- No adverse cardiovascular events, such as angina or syncope, occurred during training in either group.
- Training was supervised by cardiologists, rehabilitation therapists, and nurses.
- Exercise assignment was clinically determined based on baseline cardiopulmonary function, exercise tolerance, and risk stratification.