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, per the Mayo Clinic. It can affect any part of the body but is commonly seen in feet, ankles, hands and arms.

Swollen extremities can happen for a variety of reasons and be treated with different 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.

"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.

Potassium is an element in the body and an electrolyte that's critical for muscle function, especially heart function, Dr. 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," Dr. Costello says.

Cases of low potassium, formally called hypokalemia, can range from mild to severe, according to the 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," Dr. 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 have different symptoms including:

• Muscle twitches and cramps
• Muscle weakness
• Low blood pressure
• Fainting
• Excessive thirst and urination

Swollen legs and feet can also be caused by other factors like diet or even the environment, especially in hot weather. Long periods of sitting or standing and tight clothing can also lead to lower-body swelling, per the Mayo Clinic.

Swelling that isn't related to potassium or heart health is common, Dr. Costello says. "People who are on their feet all day working or lifting heavy things, that certainly puts pressure on those veins."

According to Mount Sinai, other causes of swollen feet, legs and ankles to consider include:

• A blood clot in the leg
  
• A leg infection
• An injury or lower-body surgery
• Certain medications, including high-estrogen birth control pills, diabetes medications, steroids and antidepressants
• Pregnancy
• Menstruation
• Having overweight or obesity

"Also people who have diets that are really high in salt or sodium, that also can affect that amount of fluid you retain so your blood volume is higher, which can also make your swelling worse," Dr. Costello says.

Treating low potassium levels and swelling in the feet depends on the cause. If you experience any mild to severe symptoms you should consult your doctor for an accurate diagnosis and treatment plan, per the Mayo Clinic. If swelling is being caused by salt intake, changing your eating habits can help, according to Dr. 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," Dr. 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 ease 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," Dr. Costello says.

Other options include leafy greens, beans, nuts, dairy and starchy vegetables, per the Harvard T.H. Chan School of Public Health.