<<Disclaimer: Verify this information before applying it to your situation.>> Not quite as bad as blacking out, though it could lead to it, this is often caused by low blood pressure. Generally it hits when person starts to stand up suddenly, and the world starts to go gray or red, and they sit back down suddenly, for fear of passing out. For years I had this or other symptoms that I thought were low blood sugar, but they did not always respond to eating. Then someone gave me some salt when this happened, and I was suddenly fine. Now I always try salt when I feel washed out, if it tastes good, I take it. Since quitting gluten the serious "attacks" of weakness have become a thing of the past. I think that what happened to me was that my adrenals were exhausted from dealing with gluten, and lost salt constatnly, but if I ate a meal with a lot of gluten, they crashed. Some of you may find that salt helps you or someone you know with these problems. I put it in water, 1/8 tsp per 8 pz water (That's a pinch between thumb and forefinger), and go by taste. When really deficient, the salt will be undetectable or, will taste really good. Donna