I think everybody is different but there is a safe range (3.5 -5) for a reason. its the unsubjective safe range. I am a survivor of potassium levels being too low and too high. My lowest was .07 which resulted in cardiac arrest which obviously pulled through although was inconducive with life. i had no symptoms prior to this except siezures when i got to hot, No muscle weakness cramping heart palpitations nothing. And my high was 9. but with this i had symptoms. couldnt stop throwing up, was the weakest i have ever felt heart racing hot flushes and delerious.