Lifestyle

6 Signs of Low Potassium Most People Blame on Getting Older

By Erica Coleman · October 23, 2026

Tired legs, a stubborn case of constipation, or a heartbeat that seems to skip now and then are easy to write off as part of getting older. They can also be signs that the level of potassium in your blood has dropped too low.

Potassium is an electrolyte, a mineral that carries an electric charge in the body’s fluids. Cleveland Clinic says your body needs it for your cells, muscles and nerves to function correctly, and for a healthy heart and digestive system. When the blood level falls below normal, the medical name is hypokalemia.

A small drop often causes no symptoms at all. When it does, MedlinePlus lists constipation, skipped heartbeats or palpitations, fatigue, muscle weakness or spasms, and tingling or numbness among the mild to moderate signs. Cleveland Clinic names muscle cramps among the signs of more severe cases. Here are the six to know.

Muscle weakness. Arms and legs that feel heavy or tire quickly can come from low potassium, because muscles need the mineral to work properly.

Muscle cramps and spasms. MedlinePlus lists spasms, and the Merck Manual says a larger drop can make muscles cramp and twitch. Cramps are easy to blame on age or a long day on your feet.

Fatigue. Cleveland Clinic describes it as extreme tiredness. It is one of the vaguest symptoms, which is why it is so often overlooked.

Constipation. Potassium also matters for digestion, and a sluggish gut is one of the mild signs listed by both MedlinePlus and Cleveland Clinic.

Skipped beats or palpitations. A fluttering or pounding heart deserves attention. MedlinePlus says a large drop in potassium can lead to abnormal heart rhythms, especially in people with heart disease, and may leave you lightheaded or faint. Merck says rhythm problems can develop even after a slight drop in people who already have a heart disorder or take the heart drug digoxin.

Tingling or numbness. Pins and needles can have many causes, and low potassium is one of them.

Diet is rarely the reason. Merck says hypokalemia is rarely caused by eating too little potassium, because so many foods contain it. Most often, the body loses too much. The usual culprits are vomiting, diarrhea and long-term laxative use, according to Merck, along with diuretics, often called water pills, which can cause the kidneys to flush out extra potassium in urine. Cleveland Clinic adds excessive sweating, alcohol use disorder, low magnesium, chronic kidney disease, certain adrenal conditions, and some other medicines, including insulin and corticosteroids.

A simple blood test finds it. MedlinePlus gives a normal range of 3.5 to 5.1 mEq/L, and your doctor may also order an ECG to check your heart rhythm. Mild cases are usually treated with potassium pills, and severe cases may need potassium through a vein. If you take a diuretic, your provider may switch you to a potassium-sparing type or add a supplement. Do not start potassium supplements or stop a prescribed medicine on your own.

MedlinePlus advises contacting your provider right away if you have been vomiting or have had heavy diarrhea, or if you take diuretics and notice symptoms of low potassium. Untreated, a severe drop can cause dangerous heart rhythm problems.

This article is for general information and is not medical advice. Talk with your doctor about any symptoms and before making changes to your medicines or supplements. This article was produced with the assistance of AI and fact-checked against the sources cited by LightWave Reports.