Hypokalemia is a medical condition characterized by an abnormally low level of potassium in the blood.1 Potassium is an essential electrolyte that plays a crucial role in the activity of your muscles, nerves, heart, and cells.2 Because potassium impacts so many bodily functions, the symptoms of hypokalemia are wide-ranging.
Hypokalemia symptoms may include muscle weakness, muscle cramps, fatigue, constipation, irregular heart rhythms, and palpitations. The symptoms can vary in severity, though most cases are mild to moderate.31
Hypokalemia is one of the most common electrolyte disorders.3 Most cases of hypokalemia aren’t caused by a lack of potassium in your diet. The condition more commonly develops due to medical issues like diarrhea, vomiting, or heavy sweating.4 Knowing the symptoms of hypokalemia may help you realize that your medical issue is causing complications, leading you to get the diagnosis and treatment you need.
Muscle Weakness
Hypokalemia can lead to muscle weakness, typically starting in the legs and then moving to muscles in the upper half of your body. In severe cases, the weakness can get so bad that it leads to paralysis.
Depending on which muscles are affected, the weakness can lead to other symptoms. For instance, if the muscles in your gastrointestinal tract are weakened, you can experience symptoms like nausea and vomiting. If your respiratory muscles weaken in severe cases, you can experience serious complications like respiratory failure or even death.
Muscle weakness occurs because potassium is essential for the proper function of muscle cells, including the contraction and relaxation of muscles. When potassium levels are low, muscle cells have difficulty maintaining their normal function, resulting in weakness.3
Besides weakness, you might experience cramping or spasms in your muscles. It’s also possible to experience muscle damage in severe cases. Medically referred to as rhabdomyolysis, your muscle tissue can break down and cause you weakness and pain.5
Constipation
Low potassium levels in the blood can lead to constipation.1 This symptom occurs because potassium plays a role in muscle contractions throughout the body, including the muscles in the digestive tract.3 When potassium levels are too low, it can affect the normal rhythmic contractions of the intestines that propel food and waste through the digestive system.
In cases of hypokalemia, the muscles in the digestive tract may not contract as efficiently as they should, which can slow the movement of stool through the intestines. This delayed transit time can lead to constipation.5
Fatigue
People with hypokalemia may notice they have a lack of energy or motivation.1 Fatigue is a common symptom of hypokalemia, as potassium is necessary for optimal nerve and muscle function.6 When potassium levels are low, the body’s overall energy levels may drop, leading to persistent tiredness.
Heartbeat Irregularities
A small drop in potassium in your blood might cause you to feel as though your heart is fluttering or skipping beats. These are called palpitations. Larger drops of blood potassium can lead to arrhythmia, which is an irregular heartbeat.1
Potassium is crucial for maintaining the electrical signals that regulate the heartbeat. Low potassium levels can disrupt these signals, leading to arrhythmia.7 Besides palpitations, you may experience lightheadedness or fainting if you have arrhythmia.1
The risk of arrhythmia associated with hypokalemia is usually highest among people who are older or who have heart disease.3
Numbness and Tingling
Hypokalemia can affect nerve function, leading to numbness and tingling sensations. This change in feeling often starts in the extremities, such as the hands and feet.1
Numbness and tingling are symptoms of hypokalemia because potassium is involved in maintaining the proper function of nerve cells and their ability to transmit signals.8 When potassium levels are low, nerve cells may not function as well, resulting in these abnormal sensations.
Increased Urination and Thirst
Some people with hypokalemia may experience increased urination and thirst. This can happen if potassium blood levels stay low for an extended period of time and the kidneys become damaged because of it.5 As the kidneys make more urine, you’ll become thirstier because your body is signaling you to keep your fluid balanced.
Editor’s Note: You can find out what your blood potassium level is through a blood test. For adults, the normal potassium range is about 3.7-5.2 milliequivalents per liter (mEq/L).1 For children, the normal range is about 3-3.5 mEq/L.9
Symptoms in Children
Most children will only start experiencing symptoms if the potassium in their blood drops below the 3 mEq/L threshold.9
Symptoms of hypokalemia in children are similar to those in adults and may include:9
- Muscular weakness
- Muscle cramps
- Constipation
- Cardiac arrythmias and palpitations
- Kidney dysfunction
If muscle weakness affects the respiratory muscles, respiratory failure or death can occur.9
If your child experiences intermittent muscle weakness, especially when there is a family history of periodic paralysis (a condition that causes episodes of extreme muscle weakness), reach out to your healthcare provider for evaluation and guidance.10
When to Contact a Healthcare Provider
Consider promptly contacting a healthcare provider if you’ve experienced persistent vomiting or prolonged episodes of diarrhea. Also consider getting medical guidance if you’re currently taking diuretic medications and are exhibiting symptoms of hypokalemia.1 The healthcare provider may order a blood test to see how much potassium is in your blood.
If your hypokalemia is mild, the healthcare provider may recommend taking oral potassium supplements and eating foods high in potassium.1 Foods high in potassium include leafy greens, fruits from vines, root vegetables, and citrus fruits.2
In cases of severe hypokalemia, potassium may need to be administered through a vein (intravenous, IV).1
A Quick Review
Hypokalemia is a condition characterized by low potassium levels in the blood. Because potassium is essential to so many bodily functions, having low levels of the mineral can lead to a range of symptoms. Symptoms of hypokalemia include muscle weakness, cramping, and twitching. You might also experience constipation, fatigue, heart palpitations, arrhythmia, numbness and tingling, and increased urination and thirst. Children with hypokalemia can experience similar symptoms. If your potassium levels are slightly below normal, you might experience mild, moderate, or even no symptoms. If your levels drop more, your symptoms can be more serious.1 Recognizing the symptoms of hypokalemia is essential for early diagnosis and treatment.