# Effect of high-intensity interval training on cardiovascular disease risk factors and body composition in psoriatic arthritis: a randomised controlled trial

PMID: 30402265
Journal: RMD open
Published: 2018
Authors: Thomsen RS, Nilsen TIL, Haugeberg G, Bye A, Kavanaugh A, Hoff M

## Question

Does 11 weeks of HIIT improve cardiorespiratory fitness, cardiovascular risk factors, and body composition in adults with psoriatic arthritis?

## Summary

This randomized controlled trial tested 11 weeks of HIIT in adults with psoriatic arthritis. Participants did two supervised stationary-bike HIIT sessions and one self-guided HIIT session each week. Compared with controls, HIIT substantially improved VO2max and reduced truncal fat at 3 months, with VO2max benefits still evident at 9 months. Disease activity was reported as stable in related work; one participant left because the intervention felt too hard after a previous stroke, and no other adverse events were reported.

## Population

- Adults with psoriatic arthritis fulfilling CASPAR criteria, not already doing regular vigorous endurance exercise.
- Sample size: 61
- Age: HIIT mean 50.5 years; control mean 44.9 years
- Sex: HIIT 70% female; control 65% female
- Fitness level: Sedentary or not regularly vigorous; baseline VO2max around 29-31 ml/kg/min
- Health status: Psoriatic arthritis with cardiovascular risk concerns; unstable CVD and severe pulmonary disease excluded.

## Methodology

- Parallel-group randomized controlled trial.
- 11 weeks intervention with 9-month follow-up
- St. Olavs Hospital and NTNU/CERG in Trondheim, Norway.
- Randomized and controlled study design.

## Protocol

- 4 x 4-minute HIIT for psoriatic arthritis.
- Modality: Stationary cycling plus self-guided endurance exercise.
- Work intervals: 4 min.
- Recovery: 3 min active recovery.
- Sets or repetitions: 4 intervals.
- Intensity: 85-95% HRmax, recovery at 70% HRmax.
- Session duration: Approximately 35-40 min.
- Frequency: 3 sessions/week.
- Program length: 11 weeks.
- Maintain usual exercise habits.
- Modality: No assigned exercise change.
- Program length: 11 weeks.

## Outcomes

### VO2max
Status: improved
HIIT substantially improved VO2max compared with control at 3 months and effect remained evident at 9 months.

Between-group difference at 3 months 3.72 ml/kg/min, 95% CI 2.38 to 5.06; authors state 13.5% HIIT increase.

### Truncal fat percentage
Status: improved
HIIT reduced truncal fat compared with control at 3 months.

Between-group difference -1.28 percentage points, 95% CI -2.51 to -0.05.

### Safety
Status: mixed
One participant left because the intervention was too hard due to prior-stroke sequelae; no other adverse events were reported.

## Practical Insights

- 4 x 4 HIIT has strong protocol detail and can improve VO2max in a screened inflammatory arthritis population.
- Self-guided HIIT may not reach the same intensity as supervised HIIT.
- Clinical pages should mention that unstable cardiovascular and severe pulmonary disease were excluded.

## Limitations

- Small sample.
- Clinical special population.
- Control was not attention-matched.
- Self-guided session intensity was only moderate on average.
- Follow-up exercise behavior was less controlled.

## Safety And Adherence

- One HIIT participant left because sequelae after a previous stroke made the intervention too hard.
- No other adverse events were reported during the intervention.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/30402265/) (pubmed)
- [DOI](https://doi.org/10.1136/rmdopen-2018-000729) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203095/) (full text)

## Agent Guidance

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