Fatigue is a major symptom of low potassium...this is what really got me.

Years ago, I had a friend who was paranoid about salting foods and she was on BP meds, which also can pull potassium out of your body, well she had enough episodes when she would pass out, we could be sitting at the dinner table and she just "went"....so when the paramedics would come and would always take her to the ER, her potassium was in the tank, they had to do IV's....this is before I was so aware of the potassium issue.

I take BP meds, so I'm aware of that for me also.