Complications of High Potassium Levels

Medically Reviewed by Nayana Ambardekar, MD on March 17, 2024
2 min read

Potassium is an important nutrient, but when you have too much in your blood, it can cause health problems like irregular heartbeats. That's why your doctor always checks your potassium levels at your annual physical exam.

Some complications you could get from potassium levels that are too high include:

Irregular heartbeats(arrhythmias). Potassium helps keep your heart beating at the right pace. It does this by helping to control the electrical signals of the myocardium -- the middle layer of your heart muscle. When your potassium level is too high, it can lead to an irregular heartbeat. You might notice symptoms like:

  • Fluttering sensation in your chest
  • Heart feels like it's "racing" or "pounding"
  • Slower than usual heartbeat
  • Chest pain
  • Shortness of breath
  • Feel lightheaded or dizzy
  • Sweating
  • Anxiety
  • Fatigue

Heart attack. Though it's not common, an irregular heartbeat, left untreated, can cause a heart attack. Tell your doctor if you're having any of the symptoms of irregular heartbeat and call 911 if you have chest pain or pressure.  

Muscle weakness or paralysis. Because potassium helps your muscles and nerves signal each other, high or low levels can affect how your muscles work. High potassium levels can lead to weakness or paralysis of the muscle in your feet and legs or your respiratory muscles. These problems can also be caused by a number of other conditions. If you get these symptoms, get medical help right away.

You get potassium from eating foods that have it, such as bananas, avocados, oranges, and broccoli. When your body is working right, you get all the potassium you need from your diet.

Your kidneys take any extra potassium and send it out of your body when you pee. Sometimes your kidneys aren't able to do this job and you can end up with too much potassium in your blood.

A normal potassium level for adults is between 3.5 and 5.5 millimoles per liter (mmol/L). If your potassium level is above the normal amount, it can lead to health problems. If your potassium level is above 6.5 mmol/L, it's dangerously high, and you need medical care right away.