Can Low Potassium Cause Swelling in the Feet?

Edema is a condition that causes fluid to build up in your tissues, causing parts of the body to swell, according to Mayo Clinic. It can affect any part of the body but commonly occurs in the feet, ankles, hands, and arms.
Swollen extremities can happen for a variety of reasons and have different treatment methods. Low levels of potassium may be an underlying cause for swelling in the legs and feet, according to Briana Costello, MD, a cardiologist at The Texas Heart Institute in Houston.
“Potassium is very much related to swelling in the legs, not directly but indirectly. People who are on diuretics or other medications often lose potassium,” Dr. Costello says.
Signs of Low Potassium
Potassium is an element in the body and an electrolyte that’s critical for muscle function, especially heart function, Costello says.
“Normal people have a potassium level that’s anywhere from 3.5 to 4.5 millimoles per liter (mmol/L). In cardiology in particular, we are very interested in potassium levels because abnormal potassium levels can cause [issues], including abnormal heart rhythms,” Costello says.
Low potassium, called hypokalemia, can range from mild to severe, according to Cleveland Clinic. In mild cases, symptoms can include:
- Constipation
- Heart palpitations
- Fatigue
- Muscle weakness and spasms
- Tingling and numbness
“Patients who don’t know they have low potassium will often say they’re having muscle cramps or their muscles feel weak or they’re having spasms,” Costello says. “In the cardiology office, we actually can see those abnormal heart rhythms that they may feel or perceive as palpitations. But they could be abnormal heart rhythms.”
More severe cases of low potassium may cause these abnormal heart rhythms as well as symptoms including:
- Low blood pressure
- Muscle cramps and spasms
- Severe muscle weakness (causing paralysis)
- Fainting
- Excessive thirst and urination
Other Causes of Swollen Feet
Other factors can cause swollen legs and feet, like diet or even the environment, especially hot weather. Long periods of sitting or standing and tight clothing can also lead to lower-body swelling, says Mayo Clinic.
Swelling that isn’t related to potassium or heart health is common, Costello says. “People who are on their feet all day working or lifting heavy things, that certainly puts pressure on those veins,” she says.
According to Cleveland Clinic, other causes of swollen feet, legs, and ankles to consider include:
- Poor nutrition
- An injury or lower-body surgery
- Certain medications, including high-estrogen birth control pills, diabetes medications, steroids, and antidepressants
- Pregnancy
- An underlying medical condition
“Also, people who have diets that are really high in salt or sodium, that also can affect the amount of fluid you retain so your blood volume is higher, which can make your swelling worse,” Costello says.
How to Limit Swelling in the Feet
Treating low potassium levels and swelling in the feet depends on the cause.
If you experience any mild to severe symptoms, consult your doctor for an accurate diagnosis and treatment plan, says Mayo Clinic.
If salt intake is causing the swelling, changing your eating habits can help, according to Costello.
“I always advocate for a low-sodium or low-salt diet. That’s pretty much across the board for anyone, even if you don’t have trouble with swelling,” Costello says. “We know that sodium intake can increase risk of high blood pressure, and it’s harder to treat. It also increases your cardiovascular risk if you have a diet high in sodium.”
Restricting the sodium in your diet, elevating your swollen feet, and trying some exercises to reduce swelling may help reduce the fluid collecting in the tissues.
If your doctor says you have low potassium, you can increase your levels with many nutritious foods that are high in the electrolyte. Spoiler alert: It’s not just bananas!
“I would argue having spinach, broccoli, and potatoes is probably better than eating a lot of bananas because of the sugar content,” Costello says.
Other options include beans, nuts, and certain types of dairy, according to the Harvard T.H. Chan School of Public Health.

Chung Yoon, MD
Medical Reviewer

Ciara Lucas, RRCA, CPT
Author
Ciara Lucas is everydayhealth.com's health writer. She is a Philadelphia-based journalist, certified personal trainer, marathoner, and indoor cycling instructor. She has previously worked at HealthDigest.com and ABC/FOX News affiliates. Ciara is a graduate of the Park School of Communications at Ithaca College.