The overall objective is to determine whether High Intensity Interval Training (HIIT) has potential to improve disease activity scores for Rheumatoid Arthritis (RA) patients. By reducing inflammation and modifying immune function HIIT may offer a substantial paradigm shift in RA care, especially in older persons with RA who experience aging related-immunesenescence, increased systemic inflammation and greater physical inactivity than young persons. Prior to embarking on a large scale trial of HIIT-induced disease modification, this pilot study aims to demonstrate that HIIT can produce measurable responses in disease activity scores and peak VO2in persons undergoing routine pharmacologic treatment for RA.

Inclusion Criteria:

• Seropositive (positive rheumatoid factor or anti-citrullinated protein antibody) or erosions typical of RA on radiographs.
• History of fulfilling 2010 ACR/EULAR Classification Criteria for RA
• Able to walk on a treadmill
• Not participating in regular physical exercise (more than 60 minutes of moderate intensity or 30 minutes of vigorous intensity exercise per week) or weight reduction dieting.
• No medication changes within the last three months.
• Willing to forego knee joint injections, regular NSAID use, and use acetaminophen for any necessary analgesia during the course of the intervention.
• No current (within the last three weeks) pharmacologic therapy with corticosteroids.

Exclusion Criteria:

• Coronary artery disease
• Diabetes mellitus
• Chronic obstructive pulmonary disease
• Absolute contra-indications to exercise: Recent (<6 months) acute cardiac event unstable angina, uncontrolled dysrhythmias causing symptoms or hemodynamic compromise, symptomatic aortic stenosis, uncontrolled symptomatic heart failure, acute pulmonary embolus, acute myocarditis or pericarditis, suspected or known dissecting aneurism and acute systemic infection.
• Other inflammatory arthropathy or myopathy, Paget's disease, pigmented villonodular synovitis, joint infection, ochronosis, neuropathic arthropathy, osteochondromatosis, acromegaly, hemochromatosis, Wilson's disease, osteonecrosis, knee replacement.
• Contraindicated Medicine: ticlopidine, clopidogrel, dipyridamole, warfarin, heparin, enoxaparin and other blood thinners.