# Home-based high-intensity interval training improves cardiorespiratory fitness: a systematic review and meta-analysis

PMID: 38053128
Journal: BMC Sports Science, Medicine and Rehabilitation
Published: 2023 Dec 5
Authors: Tsuji K, Tsuchiya Y, Ueda H, Ochi E

## Question

Does home-based HIIT improve cardiorespiratory fitness in adults, and how does it compare with non-exercise controls, lab-based HIIT, and moderate-intensity continuous training?

## Summary

This systematic review found that home-based HIIT improved cardiorespiratory fitness compared with non-exercise controls and may be broadly comparable to lab-based HIIT or moderate continuous training. The evidence was limited by few studies, varied protocols, mixed populations, and uncertainty around intensity control.

## Population

- Adults in randomized trials of home-based HIIT, with and without clinical conditions
- Age: Adults; exact pooled age not extracted
- Sex: Men and women across included studies
- Fitness level: Varied across included RCTs
- Health status: Included adults regardless of disease or handicap status

## Methodology

- Systematic review and random-effects meta-analysis of randomized controlled trials
- Home-based exercise interventions across included RCTs
- Controlled study design.

## Protocol

- Home-based HIIT programs in included RCTs.
- Modality: Varied.
- Work intervals: Up to 4 minutes by review definition.
- Recovery: Low-intensity or passive recovery; varied.
- Sets or repetitions: Varied.
- Intensity: At least 80% HRmax/maximal aerobic power or high RPE.
- Session duration: Varied.
- Frequency: Varied.
- Program length: Varied.
- Progression: Varied.
- Non-exercise control, lab HIIT, or MICT.
- Modality: No exercise, lab-based HIIT, or moderate continuous exercise.
- Intensity: Comparator dependent.
- Session duration: Varied.
- Frequency: Varied.
- Program length: Varied.
- Progression: Varied.

## Outcomes

### CRF vs no exercise
Status: improved
Home-based HIIT improved cardiorespiratory fitness compared with non-exercise control.

SMD 0.61, 95% CI 0.21 to 1.02.

### CRF vs lab HIIT
Status: no clear change
Home-based HIIT was not significantly different from lab-based HIIT.

SMD -0.35, 95% CI -0.73 to 0.03.

### CRF vs MICT
Status: no clear change
Home-based HIIT was not significantly different from MICT in the main standardized analysis.

SMD 0.34, 95% CI -0.05 to 0.73.

### Safety
Status: mixed
Most studies reported no adverse events, but some clinical or disability studies reported events or pain-related dropouts.

10 of 15 studies reported no adverse events.

## Practical Insights

- Home HIIT has evidence for improving cardiorespiratory fitness versus no exercise.
- App programs should define intensity and track adherence because home studies vary widely.
- Safety guidance should be population-specific rather than based on one pooled statement.

## Limitations

- Small number of studies per comparison.
- Heterogeneous HIIT protocols and populations.
- No consensus home HIIT protocol.
- Limited patient-reported outcomes.
- Some estimates were heavily influenced by one study.

## Safety And Adherence

- All 15 included studies commented on adverse events; 10 reported none.
- Reported events included wheelchair HIIT shoulder pain, post-exercise hypotension in coronary artery disease, and cardiovascular events in HFpEF not definitely related to exercise.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/38053128/) (pubmed)
- [DOI](https://doi.org/10.1186/s13102-023-00777-2) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10696712/) (full text)

## Agent Guidance

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