# Smartphone-Assisted High-Intensity Interval Training in Inflammatory Rheumatic Disease Patients: Randomized Controlled Trial

PMID: 34673536
Journal: JMIR mHealth and uHealth
Published: 2021
Authors: Haglo H, Wang E, Berg OK, Hoff J, Helgerud J

## Question

Is smartphone-assisted HIIT comparable with supervised HIIT for cardiorespiratory fitness, quality of life, adherence, and safety in inflammatory rheumatic disease patients?

## Summary

In screened patients with inflammatory rheumatic disease, app-guided 4 x 4 minute HIIT improved VO2max about as much as supervised HIIT over 10 weeks, with no severe cardiovascular adverse events reported.

## Population

- Adults with inflammatory rheumatic diseases including rheumatoid arthritis, spondyloarthritis, and systemic lupus erythematosus
- Sample size: 40
- Age: Women mean 48 +/- 12 years; men mean 52 +/- 11 years
- Sex: 33 female, 7 male
- Fitness level: Not familiar with HIIT at enrollment
- Health status: Inflammatory rheumatic disease patients screened by a physician

## Methodology

- Two-arm randomized controlled trial
- 10 weeks
- Clinic/gym/outdoor HIIT with app-assisted or supervised delivery
- Randomized and controlled study design.

## Protocol

- App-guided HIIT.
- Modality: Walking or running on treadmill, gym, or uphill outdoor route using Myworkout GO.
- Work intervals: 4 minutes.
- Recovery: 3 minutes active recovery.
- Sets or repetitions: 4 intervals.
- Intensity: RPE 16-17, about 85-95% HRmax; app estimated intensity from speed/incline.
- Session duration: 34 minutes.
- Frequency: 2 sessions per week.
- Program length: 10 weeks.
- Progression: Speed and incline adjusted to reach target effort; automated email at halfway if <70% sessions.
- Supervised HIIT.
- Modality: Mostly treadmill clinic training, with some outdoor sessions.
- Work intervals: 4 minutes.
- Recovery: 3 minutes active recovery.
- Sets or repetitions: 4 intervals.
- Intensity: RPE 16-17, about 85-95% HRmax.
- Session duration: 34 minutes.
- Frequency: 2 sessions per week.
- Program length: 10 weeks.
- Progression: Physiotherapist/exercise physiology supervision adjusted speed and incline.

## Outcomes

### VO2max
Status: improved
Both app-guided and supervised HIIT improved VO2max similarly.

VO2max increased p<0.001; supervised +3.6 +/- 1.3 mL/kg/min and app-guided +3.7 +/- 1.5 mL/kg/min; no between-group difference.

### Oxygen pulse
Status: improved
Oxygen pulse improved in both groups.

Time effect p<0.001; no meaningful between-group difference reported.

### HRQoL
Status: improved
Several quality-of-life domains improved over time without clear between-group differences.

Bodily pain, vitality, and social functioning improved with p values from <0.001 to 0.04.

### Safety
Status: no clear change
No severe cardiovascular adverse events were reported during testing or HIIT.

Safety events were described narratively; no severe cardiovascular events in either group.

## Practical Insights

- A 4 x 4 minute HIIT format can be delivered through a smartphone app in screened inflammatory rheumatic disease patients.
- App delivery may reduce supervision requirements but needs intensity-estimation safeguards.
- Exercise tolerance testing and medical screening were part of the safety context.

## Limitations

- Per-protocol analysis rather than full intention-to-treat.
- Motivated volunteer sample.
- App group intensity was not directly heart-rate monitored for all sessions.
- Missing HRQoL data in some app-group participants.

## Safety And Adherence

- No severe cardiovascular adverse events occurred during or after VO2max testing or HIIT. Some withdrawals were related to illness, high disease activity, plantar fasciitis, low-back disc herniation, or knee/ankle inflammation; some were considered possibly training related.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/34673536/) (pubmed)
- [DOI](https://doi.org/10.2196/28124) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8569541/) (full text)

## Agent Guidance

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