Normal Potassium Levels: High & Low Potassium, Tests & More

Mary Lucas, RN

Medically reviewed by Mary Lucas, RN

Written by Our Editorial Team

Last updated 12/15/2020

Potassium is a mineral and electrolyte that’s essential for optimal health. It plays a major role in the functioning of your muscles, nerves, digestive system and bodily organs such as your heart and kidneys.

According to the U.S. National Library of Medicine, a normal potassium level should be between 3.7 and 5.2 milliequivalents per liter.

It’s important to maintain healthy potassium levels. If your blood potassium levels are too low or high, you may experience certain symptoms. 

A low blood potassium level is referred to as hypokalemia. If your level of potassium is too low, you may experience symptoms such as fatigue, muscle weakness, numbness and a range of mild-to-serious cardiovascular issues.

A high blood potassium level is referred to as hyperkalemia. High levels of potassium often do not cause any noticeable symptoms. However, some people may experience chest pain, heart palpitations, difficulty breathing, nausea or vomiting and other symptoms.

Below, we’ve provided more information about optimal, normal potassium level, as well as the potential health issues that are associated with overly low or high potassium. We’ve also talked about what you can do to maintain a normal, healthy level of potassium.

Potassium: An Overview

Potassium is one of several minerals and electrolytes that play a major role in helping your body function normally.

Normal levels of potassium are vital for maintaining fluid and blood volume and for proper functioning of the heart, kidneys, nerves and digestive system. 

Potassium is also an essential nutrient for maintaining proper muscle function. Your muscles need potassium in order to function properly, including the muscles that control your breathing and heartbeat.

Beyond its important role in essential biological functions, potassium has a range of benefits as a mineral. For example, research shows that increasing potassium intake can help to decrease blood pressure in people with hypertension, and consequently reduce the risk of strokes.

Potassium is found in a variety of different foods, including fruit, vegetables, seafood and dairy products. It’s also available in supplements, including potassium supplements and a range of multivitamin and mineral supplements. 

While potassium is an essential mineral, more potassium isn’t always a good thing. Overly low and overly high potassium levels can both cause health issues, making it important to focus on getting a healthy, balanced intake of potassium and other minerals and nutrients. 

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What is a Normal Potassium Level?

According to the U.S. National Library of Medicine, the normal range for potassium in the blood is 3.7 to 5.2 milliequivalents per liter (mEq/L). 

A potassium level below this range may be a signal that you have a low amount of potassium in your blood, or hypokalemia. A test result above this range may signal that you have a high level of potassium, or hyperkalemia. 

Tests to check blood potassium levels are performed in a clinical laboratory setting. Different laboratories may use different reference ranges for interpreting potassium levels.  It's best to talk to your healthcare provider to learn more about their testing method and your results. 

Low Potassium Levels (Hypokalemia)

A low blood potassium level is referred to as hypokalemia. A variety of factors may contribute to low potassium levels, including the following:

  • Excessive sweating

  • Chronic kidney disease

  • Low magnesium levels

  • Eating disorders, such as bulimia

  • A diet that doesn’t contain enough potassium

  • Diarrhea, vomiting and overuse of laxatives

  • Hyperaldosteronism (overproduction of aldosterone)

  • Medications that reduce potassium levels, such as diuretics and some antibiotics

  • Certain genetic disorders, such as Bartter syndrome and hypokalemic periodic paralysis (hypoPP)

When your potassium levels only drop by a small amount, you may not notice any symptoms. In some cases, you may experience mild symptoms such as the following:

  • Fatigue

  • Constipation

  • Tingling or feelings of numbness

  • Heart palpitations or skipped heartbeats

  • Muscle weakness, spasms or damage

When your potassium level drops by a significant amount, you may experience heart arrhythmias and feelings of lightheadedness. A very low potassium level may even cause your heart to stop -- a serious, potentially fatal medical emergency referred to as sudden cardiac arrest (SCA).

High Potassium Level (Hyperkalemia)

A high blood potassium level is referred to as hyperkalemia. Numerous factors may cause your potassium levels to become overly high, including the following:

  • Reduced kidney function, such as that caused by chronic kidney disease and other health conditions that affect your kidneys

  • Burns affecting large areas of your skin

  • In rare cases, a diet that’s overly high in potassium

  • Addison disease

  • Tumors

  • Medications that increase potassium level, including angiotensin receptor blockers and ACE inhibitors 

  • Cellular or muscle damage caused by injuries, untreated seizures, alcohol abuse, illicit drug use, infections or other health conditions

  • Severe bleeding that affects your intestines and/or stomach

  • Disorders that cause the rupturing of blood cells, such as anemia

  • Excessive use of potassium supplements

A high potassium level doesn’t always cause noticeable symptoms. However, you may experience the following symptoms if your potassium level is elevated:

  • Difficulty breathing

  • Nausea

  • Chest pain

  • Heart palpitations

  • A slow, weak or irregular heartbeat

In some cases, a high potassium level may cause you to suddenly collapse due to a slow pulse or sudden cardiac arrest.

If you experience severe symptoms due to low or high potassium levels, seek medical care as soon as possible. Call 911 for urgent assistance during a medical emergency.

How to Check Your Potassium Level

If you’re worried that you may have overly low or high potassium levels, or if you’ve experienced any of the symptoms listed above, it’s best to talk to your healthcare provider.

Potassium level can be checked through a simple test called a potassium blood test. This test measures the amount of potassium in the serum, or fluid part, of your blood.  

It may also be checked as part of a basic or comprehensive metabolic panel, tests which check not just your potassium level but other electrolytes (such as sodium, magnesium and others) and also measure your blood glucose, kidney function, and other elements.

To perform this test, a professional will collect a sample of your blood using a small needle. The blood is typically drawn from a vein in your arm. The process only takes a few minutes and may cause a mild sting when the needle is inserted and removed.

Your blood sample will be sent to a laboratory, where its potassium content will be analyzed. It may take several days for you to receive the results from your potassium test. 

How to Maintain a Healthy Potassium Level

Maintaining a healthy, normal potassium level is important for your cardiovascular and general health, helping to lower your risk of serious issues such as high blood pressure, heart disease and stroke.

If you have an overly low potassium level (hypokalemia), your healthcare provider may suggest that you:

  • Eat more potassium-rich foods. Many foods, including certain fruits and vegetables, beans and peas, complex carbs, meats, seafood and others contain large amounts of potassium, making them good additions to your diet.

  • Use a potassium supplement or medication. In some causes, you may benefit from using a potassium supplement. If you have a very low potassium level, you may need to take in potassium via an intravenous drip (IV).

If your low potassium level is related to a medication, your healthcare provider may suggest making changes to your dosage or switching to a different medication. Follow your healthcare provider’s instructions exactly and don’t make any changes without their advice. 

If you have an overly high potassium level (hyperkalemia), your healthcare provider may suggest that you:

  • Reduce your consumption of foods rich in potassium.You may need to limit your consumption of certain foods that contain significant amounts of potassium, or avoid eating them altogether.

  • Reduce your consumption of salt substitutes. If you need to follow a low-salt diet, your healthcare provider may recommend limiting your consumption of or avoiding salt substitutes.

  • Stop using potassium supplements. If you take a potassium supplement, you may need to adjust your dosage or stop using your supplement.

  • Adjust or stop using certain medications. Some medications, such as medications used to treat hypertension and heart disease, may affect your potassium level. Your healthcare provider may suggest changing or stopping use of certain medications.

  • Use a diuretic (water pill). If your high potassium level is caused by a kidney issue, your healthcare provider may prescribe a diuretic, or water pill, to assist your body in expelling fluid and potassium.

If you have a very high potassium level, or experience signs of a medical emergency, you may need emergency treatment. This may involve treatment with an intravenous (IV) fluid drip, the use of medication to remove potassium before absorption or diuretics.

If your potassium level is very high due to a kidney issue, you may need to undergo kidney dialysis.

In Conclusion

Potassium is an essential mineral and electrolyte that has significant effects on your muscular and cardiovascular health.

A normal potassium level is 3.7 to 5.2 milliequivalents per liter. If your potassium level is above or below this range, talk to your healthcare provider. They may suggest making some adjustments to your diet and use of medication to bring you potassium levels back to normal. 

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

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