Effect of high-intensity interval training in physiotherapy primary care for patients with inflammatory arthritis: the ExeHeart randomised controlled trial

Abstract

Objectives: To assess the effect of high-intensity interval training (HIIT) delivered in physiotherapy primary care on the primary outcome of cardiorespiratory fitness (CRF) in patients with inflammatory arthritis (IA). Additionally, to explore the effects of HIIT on secondary outcomes, including cardiovascular disease (CVD) risk factors and disease activity.

Methods: Single-blinded randomised controlled trial with 60 patients randomly assigned to either a control group receiving usual care or an exercise group receiving usual care and 12 weeks of individualised HIIT at 90%-95% peak heart rate. Outcomes were assessed at baseline, 3 months and 6 months post baseline and included CRF measured as peak oxygen uptake (VO_2peak), classic CVD risk factors, disease activity, anthropometry and patient-reported physical activity, pain, fatigue, disease impact and exercise beliefs and self-efficacy.

Results: Intention-to-treat analysis demonstrated a significant between-group difference in VO_2peak at 3 months (2.5 mL/kg/min, 95% CI 0.9 to 4.0) and 6 months (2.6 mL/kg/min, 95% CI 0.8 to 4.3) in favour of the exercise group. A beneficial change in self-reported physical activity in favour of the exercise group was observed at 3 and 6 months. The HIIT intervention was well-tolerated with minimal adverse events and no apparent impact on disease activity. Differences in secondary outcomes related to CVD risk factors, disease impact, pain, fatigue and exercise beliefs and self-efficacy were generally small and non-significant.

Conclusion: After 12 weeks of supervised HIIT delivered in physiotherapy primary care, patients with IA demonstrated a favourable improvement in CRF, with sustained effects at 6-month follow-up.

Trial registration number: NCT04922840.

Keywords: Arthritis, Psoriatic; Arthritis, Rheumatoid; Cardiovascular Diseases; Physical Therapy Modalities; Spondylitis, Ankylosing.

Figure 1

Consolidated Standards of Reporting Trials flow diagram of study enrolment, allocation and follow-up in the ExeHeart trial. BMI, body mass index; CPET, cardiopulmonary exercise test; HIIT, high-intensity interval training; PT, physiotherapist; VO_2peak, peak oxygen uptake.

Figure 2

Mean VO_2peak in mL/kg/min across groups and study visits. Error bars represent 95% CI of means adjusted by covariates from analysis of covariance; age, gender and baseline value. Control group is shown in grey and exercise group in blue. Between-group difference at 3 months was 2.5 mL/kg/min (95% CI 0.9 to 4.0, p<0.01) and at 6 months 2.6 mL/kg/min (95% CI 0.8 to 4.3, p<0.01). ITT, Intention to Treat; VO_2peak, peak oxygen uptake in mL/kg/min.