Chronic low blood pressure with no symptoms is almost never serious. Low blood pressure can be associated with hormonal problems like underactive thyroid, diabetes mellitus, low blood sugar, liver disease, heat stroke, heart failure etc.Certain diseases like autonomic neuropathy, nutritional diseases, and cardiovascular diseases can lead to low B.P .Drink more fluids and water. Several medications can be used to treat low blood pressure especially orthostatic hypotension. A drug like fludrocortisone is often used to treat this form of low blood pressure. Consult your physician and start treatment as early as possible. I hope it helps.
Take care and regards!
Whilst I am not suggesting it is the same, I suffer from low blood pressure, even now to a degree, after I was diagnosed with Addisons disease. I find caffeine and ginseng helps although the former may not be the healthiest option but there again is salt water. I never found sodium helped certainly not in the short term.
That is truly something you need to see a doctor for. There are different causes and reasons for low blood pressure, thus the treatment differs from person to person....