What will happen to an individual if their potassium is too high?

HIgh potassium level: The effect of the potassium (K) level in the blood depends on how well the body is used to it. Dialysis patients tolerate higher K levels than do non-dialysis patients, as their bodies are used to a higher level. Common symptoms of high K are weakness of the muscles, slowing of the heart rate and possibly death due to cardiac arrest, if the K is high enough without treatment.