The effect of acidosis correction and exercise on tissue wasting and immune function in renal patients

INTERVENTION: Forty patients will be assigned randomly to the following four groups to determine whether alkali and exercise together are more effective than alkali or exercise alone: 1. Standard clinical therapy only (no exercise and target plasma bicarbonate of 24 mmol/L) 2. Additional alkali therapy (no exercise and target plasma bicarbonate of 29 mmol/L) 3. Exercise therapy without additional alkali therapy (target plasma bicarbonate of 24 mmol/L) 4. Exercise therapy and additional alkali therapy (target plasma bicarbonate of 29 mmol/L) CONDITION: Chronic kidney disease ; Urological and Genital Diseases ; Other disorders of kidney and ureter, not elsewhere classified PRIMARY OUTCOME: 1. Changes in immune function ‐ in vitro assessment of lymphocyte proliferation and neutrophil activation ; 2. Changes in body composition ‐ dual energy X‐ray absorptiometry (DEXA) scanning; ; Measurements made at zero and 6 months (end of study). SECONDARY OUTCOME: 1. Changes in exercise tolerance ‐ submaximal exercise testing (bicycle ergometry or treadmill exercise) to determine maximal oxygen uptake and lactate threshold; 2. Muscle biopsies ‐ in vitro evaluation of intracellular signalling pathways that regulate protein synthesis; 3. Changes in cardiovascular function ‐ blood pressure, pulse wave velocity, finometry; 4. Changes in quality of life measures ‐ Leicester Uraemic Symptoms Score; ; Measurements made at zero and 6 months (end of study). INCLUSION CRITERIA: Chronic kidney disease (CKD) patients at CKD stages 4 to 5.