Effectiveness and safety of high-intensity exercise in rheumatic diseases—friend or foe? A systematic review

OBJECTIVES: Despite growing evidence supporting the benefits of physical activity in patients with rheumatic and musculoskeletal diseases (RMDs), both clinicians and patients often remain cautious-particularly regarding higher intensities. Although exercise is universally recommended in international guidelines for these populations, it is frequently accompanied by warnings to engage only in moderate-intensity training. The primary objective of this systematic review was to examine the effectiveness and safety of high-intensity, land-based exercise in patients with inflammatory rheumatic conditions, compared with usual care, no intervention, or low-intensity exercise. We aimed to determine whether high-intensity exercise leads to an increase in disease activity, pain intensity, or impairment of function. METHODS: We conducted a systematic review through a systematic literature search in the electronic databases MEDLINE (via PubMed), the Cochrane Library, PEDro, and ClinicalTrials.gov. RESULTS: We identified relevant 29 studies (15 original randomized controlled trials and 14 secondary analyses or follow-up studies). The study quality as assessed using the Joanna Briggs Institute (JBI) checklist was generally adequate, with the main limitations being in patient and clinician blinding. The findings indicated that high-intensity exercise-whether aerobic, resistance-based, or in the form of high-intensity interval training (HIIT)-is safe for patients with inflammatory rheumatic diseases. We found moderate certainty evidence that high-intensity exercise does not increase disease activity, and may reduce pain and may improve function when compared with control interventions. CONCLUSION: While patients can certainly benefit from low- to moderate-intensity exercise, the current evidence does not suggest harm from high-intensity exercise. Exercise selection should follow an individualized, person-centred approach.