Sodium is known to raise blood pressure (and sometimes greatly), so doctors generally recommend limiting it. Check with your healthcare professional before you up your intake -- if you consume an amount that's not good for you, it can lead to heart failure (especially if you're older).
Other possible causes for foot, leg, and ankle swelling include certain medical conditions or body changes, such as: Natural hormonal changes: Fluctuating levels of estrogen and progesterone can cause reduced circulation in the legs, resulting in swelling.
The most common cause of foot swelling is inflammation. Inflammation can be caused by two major causes (1) infection -- this often causes redness, warmth, pain as well -- which does not seem to be what you are experiencing (2) sterile inflammation.