I experienced this issue in a personal way when my mother was in her 80s and early 90s, she experienced a few fainting episodes with the conclusion that she was dehydrated. The solution from the doctor was to drink more water to hydrate; however, the water without electrolytes would pass right through, which is why she didn't want to hydrate frequently. In her late 80s, she went to live in an Independent Living facility, and their meals were right out of the American Heart/Diabetes Associations playbook with very little to no salt added. When we got her to take her own salt shaker to the dining room, things improved. She was a survivor of a stroke and heart attack before she went to Independent Living. She continued to attend her twice weekly bridge tournaments and other outside social activities with salt shaker in pocketbook and no further episodes. I can attest to the need to revisit the low salt recommendations, as salt is an important component of a healthy diet and makes food taste better.

James DiNicolantonio's The Salt Fix: Why the Experts Got It All Wrong--and How Eating More Might Save Your Life is an excellent summary of the salt hysteria where that misguided advice is now thought of as another bulleted item on the list of terrible dietary health guidance the population has received over the past 40 years.