My sodium started running below normal. It can definitely make me feel weak and lethargic. A kidney dr recommended I take a sodium tablet every morning and keep liquids about 60 oz per day. A nurse gave me sample packets of DripDrop I mix in water to drink when I exercise at the gym. It's an electrolyte mix. Ask your dr if a sodium supplement would be helpful or harmful in your situation. Side note, people who take some medications, ex beta blockers, often have low sodium.