Magnesium & Irregular Heartbeat

A senior man has his heartbeat checked by a doctor in his office.
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Changes in the amounts of different minerals in your blood can affect many tissues, including your heart. Although your body only contains small amounts of magnesium, having too much or too little magnesium can affect your heart's rhythm. Talk to your doctor before taking magnesium or any other type of supplement.

Magnesium Sources and Function

Magnesium is the fourth most abundant mineral in the body, and approximately half of your body's magnesium is stored in your bones. Most of the rest of the magnesium is found inside of cells and organs, but a small amount circulates through your body in the blood. Magnesium keeps your nerves and muscles working properly, supports your immune system and regulates your blood sugar and blood pressure levels. Green vegetables, some legumes, whole grains and "hard" tap water all provide magnesium.

Magnesium Deficiency

If you do not get enough magnesium in your diet, it can cause a variety of problems. Early signs of magnesium deficiency include nausea, vomiting and weakness. As the deficiency gets worse, your nerves and muscles can be affected, causing numbness, tingling and muscle spasms. Your heart can also be affected, resulting in an arrhythmia. A lack of magnesium can also cause the amount of calcium in your blood to drop, leading to an irregular heartbeat.

Magnesium as Arrhythmia Treatment

Because magnesium plays such a pivotal role in controlling your heart rhythm, it is sometimes given intravenously in hospitals to patients who are experiencing heart trouble. This helps prevent a type of arrhythmia known as atrial fibrillation. People who have congestive heart failure also have an increased chance of developing an irregular heartbeat. If you have congestive heart failure, your doctor may tell you to take a magnesium supplement.


Although magnesium supplements may help you keep your heart rhythm normal, too much magnesium can be toxic. One of the earliest signs of magnesium toxicity is diarrhea. Magnesium toxicity can also cause low blood pressure, confusion, lethargy, poor kidney function and abnormalities in your heart rate. Talk to your doctor before taking any sort of supplement that contains magnesium so that you do not accidentally overdose.