- . Exclusion criteria are: active lifestyle (exercise >1 hour/wk); body mass index > 40; MRI contraindications; history of neurological disease, prior neurosurgery; diagnosed and/or treated type 1 or 2 diabetes; pregnancy; acute or subacute active cardiac disease (ongoing chest pain or myocardial infarction < 3 months); significant orthopedic or musculoskeletal condition that limits weight bearing.