80 patients with rheumatoid arthritis who are being treated with either interleukin-6 receptor blockers (IL-6Rb) or tumor necrosis factor inhibitors (TNFi) for a minimum of four months prior to enrollment will be recruited and undergo baseline testing, including examination, biochemistry, ECG, DXA, OGTT, pulmonary function, VO2max, echocardiography, cardiac MRI.~After baseline testing, 40 patients in IL-6 receptor blocker treatment and 40 patients in TNF inhibitor treatment.will be randomly allocated into one group receiving standard of care (control group) or a group performing supervised high-intensity interval training three times a week over a period of 12 weeks. The randomization procedure involves a computer-generated block randomization schedule in a ratio of 1:1 stratified by sex by an independent person. Following the 12-week intervention period, all groups will complete a series of follow-up tests (as baseline testing).
The present study will investigative the physiological effects of the cytokines interleukin-6 (IL-6) and tumor necrosis factor (TNF) on the adaptive changes to exercise in patients with rheumatoid arthritis. The investigators hypothesize that blockage of IL-6 receptors will decrease the cardiac and metabolic adaptations to exercise training compared to the inhibition of TNF. 80 patients will be included in a 12-week investigator blinded randomised exercise training intervention study.