# Effects of High-Intensity Interval Training versus Continuous Training on Physical Fitness, Cardiovascular Function and Quality of Life in Heart Failure Patients

PMID: 26517867
Journal: PloS one
Published: 2015
Authors: Benda NM, Seeger JP, Stevens GG, Hijmans-Kersten BT, van Dijk AP, Bellersen L, Lamfers EJ, Hopman MT, Thijssen DH

## Question

Is a feasible low-frequency cycling HIIT protocol superior to continuous training for improving physical fitness, cardiovascular function, and quality of life in stable heart failure patients?

## Summary

In stable NYHA II-III heart failure patients, 12 weeks of supervised cycling HIIT twice weekly improved fitness measures about as much as moderate continuous cycling. The HIIT protocol was designed to be feasible, with 10 one-minute high-intensity intervals at 90% maximal workload and long low-intensity recoveries, but it did not outperform continuous training or improve resting cardiovascular structure/function or overall quality of life.

## Population

- Stable NYHA II-III heart failure patients
- Sample size: 29
- Age: Training completers 64 +/- 8 years
- Sex: Training completers 19 men, 1 woman
- Fitness level: Clinical heart failure rehabilitation population
- Health status: LVEF about 38 +/- 6%, clinically and pharmacologically stable

## Methodology

- Allocated exercise comparison with non-randomized control group
- 12 weeks
- Hospital or rehabilitation setting supervised by physiotherapists
- Controlled study design.

## Protocol

- HIT.
- Modality: Cycle ergometer.
- Work intervals: 1 minute at 90% maximal workload.
- Recovery: 2.5 minutes at 30% maximal workload.
- Sets or repetitions: 10 intervals.
- Intensity: 90% maximal workload; Borg 15-17 target.
- Session duration: 50 minutes including warm-up and cool-down.
- Frequency: 2 sessions per week.
- Program length: 12 weeks.
- Progression: Workload increased during training based on Borg scores.
- Continuous training.
- Modality: Cycle ergometer.
- Work intervals: 30 minutes continuous.
- Sets or repetitions: One continuous block.
- Intensity: 60-75% maximal workload; Borg 12-14.
- Session duration: 45 minutes including warm-up and cool-down.
- Frequency: 2 sessions per week.
- Program length: 12 weeks.
- Progression: Workload increased based on Borg scores.

## Outcomes

### Fitness
Status: improved
Training improved maximal workload, predicted-relative VO2peak, oxygen uptake at anaerobic threshold, and maximal oxygen pulse.

All p<0.05 for time effects; no HIT versus CT differences.

### Superiority
Status: no clear change
HIT was not superior to CT for fitness, cardiovascular function, or quality of life.

Time-by-group effects non-significant.

### Vascular
Status: no clear change
No significant changes in measured vascular function/structure.

### QoL
Status: mixed
SF-36 physical function improved, but SF-36 total and MLHFQ did not.

SF-36 physical function p<0.05; total SF-36 and MLHFQ not significant.

## Practical Insights

- For high-risk clinical populations, feasibility can be improved with twice-weekly sessions and long recoveries.
- HIIT is not automatically superior to continuous training when total workload and supervision are controlled.

## Limitations

- Small sample
- Non-randomized control group
- Limited power for HIT versus CT differences
- No comparison of different HIT interval lengths

## Safety And Adherence

- One patient in each training group dropped out due to musculoskeletal complaints.
- One patient in each training group dropped out due to progression of heart failure.
- The study was monitored by a data safety monitoring board.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/26517867/) (pubmed)
- [DOI](https://doi.org/10.1371/journal.pone.0141256) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4627811/) (full text)

## Agent Guidance

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