Salt Intake: Historical Advice vs. Modern Health - Expert Explanation

Question
Hi Maggie. While in the army in India during WW2 we were encouraged to take in as much salt as possible because otherwise we would stop perspiring and suffer from heatstroke.
Now we are told to avoid salt completely as it is bad for the heart. Has medical opinion changed?
Thanks for your time.
John Weir. (UK)

Answer
Thank you for your service, Sir!  Here's the deal:  The practice was right but they gave you the wrong rationale.  For those who will be perspiring excessively or consuming a lot of water and therefore urinating frequently, consuming sodium can help prevent seizures.  (Sodium carries an electrical charge and is integral in the process of nerve conduction, as it trades places with potassium on the cell membrane and forms the nerve impulse.) Now, if you don't plan to be perspiring or urinating excessively, excessive sodium intake (more than 4,000 milligrams of sodium per day) could increase your blood pressure slightly and put you at risk for stroke and kidney damage, but to a lesser degree than other food culprits--saturated and trans fats, specifically.
Thanks for your question!

Maggie Smith, RN, MSN