Potassium is a mineral and electrolyte that plays a vital role in many of your body's functions. In the heart, it helps maintain the electrical signaling that keeps the organ beating, according to the American Heart Association. It also helps muscles and nerve cells contract and regulates sodium levels, according to the Merck Manual.
Too little potassium, a condition called hypokalemia, can be life-threatening.
Fortunately, a potassium deficiency can usually be reversed with oral or intravenous potassium supplements. The time it takes to correct the deficiency usually depends on how low your potassium supplies are, says Maria DeVita, MD, chief of nephrology at Lenox Hill Hospital in New York City. Doctors should be able to correct severe deficiencies in the hospital in just a few hours, she explains. Or it can be done in an outpatient setting over a few days.
How Much Potassium Do You Need?
Normal potassium levels in your blood should stay between about 3.8 and 5 millimoles per liter (mmol/L), Gerald Hladik, MD, chief of the Division of Nephrology and Hypertension at the University of North Carolina School of Medicine in Chapel Hill, tells LIVESTRONG.com.
Most people should be able to maintain that level by getting the Recommended Daily Intake (RDI) of potassium in their diet. The National Institutes of Health suggests men age 19 and over take in a minimum of 3,400 milligrams a day while women 19 and over get at least 2,600 milligrams daily. Good sources of potassium include potatoes, milk, legumes, yogurt and, of course, bananas.
When hypokalemia occurs, it's not usually from problems with what you're eating. Instead, it may be because you're losing the mineral through urine, sweat or stool, according to the National Organization for Rare Disorders. And that can happen as a result of taking diuretic medications, overusing laxatives, having chronic diarrhea or vomiting, not getting enough magnesium, eating disorders such as bulimia, chronic kidney disease and certain genetic disorders.
Some psychiatric drugs can lead to hypokalemia too, per the NCBI. People with inflammatory bowel diseases like Crohn's disease or ulcerative colitis may also be prone to low potassium levels, according to the National Institutes of Health.
Symptoms of Hypokalemia
Many cases of hypokalemia, even serious ones, have no symptoms, according to the Merck Manual. When they do occur, hypokalemia symptoms can be vague, including feeling tired and weak, having muscle cramps and being constipated, per the Mayo Clinic.
A more serious indication of hypokalemia is abnormal heart rhythms. According to the Mayo Clinic, most cases of low potassium are detected by accident when you get a blood test for something else.
How Hypokalemia Is Treated
The most important goal of treatment for hypokalemia is to prevent abnormal heartbeats, which can be life-threatening, according to a September 2015 article in the journal American Family Physician. If the deficiency is severe, potassium levels need to be elevated quickly, something which has to be done under a doctor's supervision.
"If you're really deficient, it needs to be monitored pretty closely," Dr. DeVita says. Part of the reason is to avoid a potassium overload, or hyperkalemia, which can have equally dangerous consequences.
Then the underlying causes need to be addressed. This could mean discontinuing a diuretic that's responsible for flushing out too much potassium or managing a condition that's leading to chronic diarrhea and/or vomiting. Mild cases of hypokalemia can be treated by increasing dietary potassium, according to the American Family Physician report, which notes that supplemental potassium chloride can be helpful.
- American Heart Association: “Hyperkalemia (High Potassium)”
- Merck Manual: “Overview of Disorders of Potassium Concentration”
- National Center for Biotechnology Information: “Hypokalemia”
- National Institutes of Health: “Potassium”
- National Organization for Rare Disorders: “Hypokalemia”
- Merck Manual: “Hypokalemia”
- Mayo Clinic: “Low potassium (hypokalemia)”
- American Family Physician: “Potassium Disorders: Hypokalemia and Hyperkalemia”