3 Serious Potassium Deficiency Symptoms to Watch Out For

Muscle cramps, muscle spasms, and cardiac arrhythmias can be common potassium deficiency symptoms. Here is what you need to know.

potassium deficiency symptoms

One banana contains 422 milligrams of potassium.

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The most dangerous, direct and severe potassium deficiency symptoms are painful muscle cramps and spasms, muscle weakness, and heartbeat irregularities.[1,2] These increases or decreases in heart rate can be especially damaging in cases where other heart problems also exist, and the muscle cramps can be debilitating when they occur during strenuous exercise. Fortunately, these potassium deficiency symptoms are easy to avoid and correct with a nutritious diet.

Potassium and Muscles

Muscle cells and the neuron cells that cause them to flex (contract) are especially reliant on steady potassium levels. Potassium ensures that electrical signals are not sent to the muscles too rapidly.[3] Spasms and cramps can result from potassium deficiency because the muscles receive too many signals to contract and are not given enough time to relax. This can cause muscles to contract in a constant, painful, uncontrolled manner. 

The Heart Is Also A Muscle

Cardiac muscle is also sensitive to potassium deficiency. Although muscle cells in the heart respond much more slowly to electrical signals and are not susceptible to spasms, they will still contract more easily than normal when potassium is deficient.[4] This can cause the heart to beat in an abnormal rhythm, a condition called arrhythmia.

Normally, a heart cell must receive a certain amount of electricity in order to contract. This threshold is reduced in a state of potassium deficiency, making the cell able to contract earlier than it normally would.[5] The cell will also relax more slowly, making its next contraction later than it would normally be. For this reason, a symptom of arrhythmia can be either an increase or a decrease in heart rate. According to one study, this complication is rare in otherwise healthy individuals but becomes common and serious when combined with other heart conditions such as bradycardia or cellular desynchronisation.[6]

Easy Steps to Correct Potassium Deficiency Symptoms

Supplementing potassium is an effective way to solve potassium deficiency.[6] There is little risk in taking frequent or high doses, as it takes an extremely high blood potassium level to cause health problems.[7] Other than supplements that can be found at nutrition stores, several foods contain high quantities of potassium. Just two servings of bananas can increase blood potassium by 4.4% after one hour.[8] Other high potassium foods include:

Many common health conditions may be the result of nutritional deficiencies. Learn more about serotonin deficiency, GABA deficiency, magnesium deficiency, and deficiencies that cause fatigue.

Share Your Experience

Have you experienced low potassium symptoms? Have certain foods helped you to eliminate muscle cramps and spasms? Share your experience in the comments section below.

—Jeff Riddle

[1] A.D.A.M. Medical Encyclopedia.

[2] Acta Med Scand Suppl. 1981;647:61-6.

[3] Biochemistry. 5th edition.

[4] Magnesium. 1984;3(4-6):289-300.

[5] Europace. 2008 Oct;10(10):1

[6] Arch Mal Coeur Vaiss. 1984 Apr;77 Spec No:17-22.

[7] Angiology. 1978 Mar;29(3):194-205.

[8] J Athl Train. 2012 Nov-Dec; 47(6): 648–654.

This article was originally published in 2015. It has since been updated. 

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  • Lately I have been experiencing muscle cramps after I go to bed; especially when I stretch my legs. I also notice my toes also gets cramped when I’m driving and both cramps are very painful. Lately I’ve also noticed some tugging pains in my chest. I also take HBP meds, HCTZ at 25mg once a day. Can this medication be depleting my body from much needed nutrients such as potassium and other necessary nutrients. I do not supplement regularly with added vitamins etc.
    Looking forward to your reply.

  • I read somewhere that nighttime leg cramps were from a lack of water. Started drinking a large glass at bedtime. Reduced the frequency of cramps dramatically.

  • I have been told by a Doctor to take magnesium byglycinate till i notice loose stool as my marker as to when the amount is enough. I take 400ml night. I have noticed after a year, my stomach is upset. I have also complained about my heart pounding at rest or when i lay down for sleep. I have had it check and seems fine. I have lon the lower end of blood pressure and I am not on any medications. After reading this article, I am suspecting maybe this is too much magnesium for me.


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