“…In general, people with CKD stages 1, 2, and often 3a (Glomerular Filtration Rate (GFR) < 60 to ≥45 mL/min/1.73 m 2 ) who do not have much proteinuria and who do not have other symptomatic, debilitating comorbidities (e.g., no heart or lung failure, active cancer, vasculitis, obesity, vascular insufficiency, or uncontrolled hypertension) may have an exercise capacity which is normal or, if the person chronically exercises, above normal [ 46 , 47 ]. By contrast people with CKD stage 3b, and particularly CKD stages 4 and 5 and chronic dialysis patients, which we will refer to in this paper as advanced CKD, commonly lead more physically inactive lives [ 43 , 46 , 47 , 48 , 49 ]. In general, the more severely reduced the glomerular filtration rate (GFR), the more physically inactive [ 1 , 43 , 50 ] and the more severely impaired the exercise capacity of many CKD patients [ 37 , 46 ].…”