Just to make sure you understood me as I intended.
If you are feeling cold you are probably suffering from excess potassium from NPN or other sources.
That means sodium WILL help. The challenge is getting sodium in the best form possible which is usually a whole food source like top quality kelp, celery, cabbage etc.
The reason why trying to resolve a sodium deficiency with forms of salt is that you may end up providing your body with too much chloride as even the best forms of salt are very heavy in Sodium chloride (NACl).
For example Himalayan Salt is touted by many to be a very "healthy" form of salt with lots of trace minerals etc. It certainly is expensive.
But when you look at the breakdown:
Sodium Chloride - 98.35%
Magnesium - .07%
Sulfate - .05%
Iron - .0006%
Moisture - .026%
Insoluble - .77%