# Superior Effects of High-Intensity Interval Training Compared to Conventional Therapy on Cardiovascular and Psychological Aspects in Myocardial Infarction

PMID: 29560335
Journal: Annals of Rehabilitation Medicine
Published: 2018 Feb
Authors: Choi HY, Han HJ, Choi JW, Jung HY, Joa KL

## Question

The study compared the effects of high-intensity interval training and conventional moderate-intensity continuous training on cardiovascular function, psychological symptoms, and activity state in low- and moderate-risk phase II myocardial infarction patients.

## Summary

In low- and moderate-risk patients beginning phase II cardiac rehabilitation soon after first STEMI treated with PCI, an 18-session supervised 4 x 4-minute HIIT program improved VO2max, METs, 6-minute walk distance, activity score, depression score, and fatigue score more than matched-duration moderate-intensity continuous training. The authors reported that all 44 analyzed patients completed 18 sessions without adverse events.

## Population

- Low- and moderate-risk phase II cardiac rehabilitation patients after first-time STEMI treated with primary PCI.
- Sample size: 44
- Age: Mean 54.93 +/- 9.91 years.
- Sex: 89% male; 5 women among 44 participants.
- Fitness level: Initial VO2max 30.17 +/- 7.56 mL/kg/min, METs 8.62 +/- 2.16, 6MWT 502.88 +/- 75.99 m.
- Health status: First-time STEMI after PCI; low or moderate risk; mean LVEF 46.90% +/- 7.14%.

## Methodology

- Prospective, non-blinded randomized controlled trial comparing 18 sessions of HIIT with moderate-intensity continuous training.
- 18 sessions over an average of 9-10 weeks
- Outpatient phase II cardiac rehabilitation clinic after myocardial infarction
- Randomized and controlled study design.

## Protocol

- HIIT cardiac rehabilitation.
- Modality: Aerobic interval training.
- Work intervals: 4 minutes.
- Recovery: 3 minutes.
- Sets or repetitions: 4 intervals.
- Intensity: 85%-100% HRmax during work intervals; 50%-60% HRmax during recovery.
- Session duration: 48 minutes total: 10 minutes stretching, 5 minutes warm-up, 28 minutes main exercise, 5 minutes cool-down.
- Frequency: Average 1-2 sessions per week.
- Program length: 18 sessions over 9-10 weeks on average.
- Moderate-intensity continuous training.
- Modality: Continuous aerobic training.
- Sets or repetitions: 28 minutes continuous main exercise.
- Intensity: 60%-70% HRmax; intensity allowed conversation in full sentences.
- Session duration: 48 minutes total with same duration as HIIT.
- Frequency: Average 1-2 sessions per week.
- Program length: 18 sessions over 9-10 weeks on average.

## Outcomes

### VO2max
Status: improved
VO2max improved more in HIIT than MICT.

Abstract reports VO2max improved by 7.58 mL/kg/min in HIIT compared with 2.42 mL/kg/min in MICT, p<0.005.

### Cardiovascular and functional state
Status: improved
METs, 6MWT, and KASI improved significantly more after HIIT than after MICT.

Reported as significant between-group improvements after 18 sessions; p<0.05 threshold.

### Depression
Status: improved
HADS depression improved in HIIT and decreased in MICT; PHQ-9 tended to favor HIIT without statistical significance.

HADS-D improved by 1.89 in HIIT compared with decrement of 0.47 in MICT; PHQ-9 p=0.068.

### Fatigue
Status: improved
FSS improved more after HIIT than after MICT.

FSS improved by 6.38 in HIIT compared with decrement of 0.77 in MICT; p<0.005.

### Anxiety and insomnia
Status: no clear change
HADS anxiety and Insomnia Severity Index did not differ significantly between HIIT and MICT.

### Adverse events
Status: no clear change
All 44 analyzed patients completed 18 sessions without adverse events.

## Practical Insights

- A 4 x 4-minute HIIT structure at 85%-100% HRmax can be effective in clinically screened post-MI cardiac rehabilitation.
- The study supports matching total session duration when comparing HIIT to continuous training; the interval intensity pattern was associated with larger gains.
- For post-MI users, HIIT programming requires clinical risk stratification and should not be generalized to high-risk or unsupervised settings.

## Limitations

- Small sample size.
- High-risk patients were excluded.
- The sample was predominantly male.
- Non-blinded trial design.
- Social support and other unmeasured factors could have affected psychological outcomes.
- No long-term follow-up or clinical event endpoint was reported.

## Safety And Adherence

- All 44 analyzed patients completed 18 sessions without any adverse event.
- One patient assigned to HIIT and one assigned to MICT did not finish all sessions because of ankle injury and occupational reasons.
- High-risk patients were excluded because the authors were not sure of HIIT safety for those patients.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/29560335/) (pubmed)
- [DOI](https://doi.org/10.5535/arm.2018.42.1.145) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5852218/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.