| Prolonged lows near the zero mark have caused brain damage, according to some nebulous studies, but otherwise I have not heard of brain damage mentioned outside of those circumstances. It's very rare to die from hypoglycemia, but my grandmother did, and I know that my liver makes no response to low blood sugar (no rebound), so perhaps there's a genetic condition to be mindful of. If you do rebound, a bad low can send your blood sugar bouncing back and forth for a while (even days, I've heard), so going very low must be avoided even more diligently than a high..... at least for me. I barely consider minor lows if I'm in a position to monitor them, although if they happen often over a 1 1/2 to 2-day period I change my insulin doses. | 
