This research program aims to comprehensively investigate the clinical, physiological, metabolic, and molecular effects of reducing sedentary behavior in rheumatoid arthritis. This 4-month parallel-group randomized controlled trial aims to investigate the feasibility and efficacy of a newly developed personalized intervention focused on replacing sedentary time with light-(or very light-) intensity physical activity in rheumatoid arthritis. A multitude of gold-standard techniques will be applied to evaluate the effects of the intervention on several outcomes, including sedentary time (primary outcome), physical activity levels, clinical parameters specific to each condition, cardiometabolic risk factors, immune function, and health-related quality of life. In addition, skeletal muscle and blood samples will be collected and a variety of molecular analyses will be performed to gather knowledge on the potential mechanisms which underpin the response to this intervention.