Handgrip Exercise Training and CKD

Inclusion Criteria: * Patients with CKD (Stages IIIa and IV), * Ages 45-85 years who do not regularly exercise (defined as exercising less than 20 minutes twice per week), willing and able to cooperate with the protocol. * CKD Stages III and IV will be defined as reduction in estimated glomerular filtration rate (eGFR) to 15-59 cc/minute as calculated by the modified CKD-EPI equations. * Patients with CKD must have stable renal function (no greater than a 20% reduction in eGFR over the prior 3 months). Exclusion Criteria: * Severe CKD (eGFR\<15 cc/minute) * Metabolic alkalosis (serum bicarbonate \> 28 meq/L) * Ongoing drug or alcohol abuse * Diabetic neuropathy * Any serious systemic disease that might influence survival * Severe anemia with hgb level \<10 g/dL * Clinical evidence of congestive heart failure or ejection fraction below 35%, symptomatic heart disease determined by prior electrocardiogram, stress test, and/or history, treatment with central alpha agonists (clonidine) * Uncontrolled hypertension with BP greater than 170/100 mm Hg * Low blood pressure with BP less than 100/50 * Pregnancy or plans to become pregnant * Current treatment with MAO inhibitors * Inability to perform handgrip exercise