Heart palpitations, a type of cardiac arrhythmia, have been described as an electrical storm in your heart. Heart palpitations can range from mild and sporadic occurrences to life-threatening emergencies. The most common type of heart palpitation is called supraventricular tachycardia, according to the University of Maryland Medical Center. This condition originates in your heart's upper chambers. Magnesium and calcium play important roles in maintaining healthy nerve and muscle function, and imbalances or deficiencies of these nutrients can contribute to your risk for developing heart palpitations.
Magnesium and calcium work together, counterbalancing each other in some of their functions. Magnesium signals muscles to relax, while calcium prompts muscle contraction. Both are also necessary for proper nerve function. Your nerves use calcium to convert an electrical nerve impulse into a chemical burst that spans the space between two nerve cells to activate a recipient nerve or muscle. Magnesium regulates calcium levels in nerves, preventing excess calcium accumulation that can lead to over-excitability.
Optimal magnesium levels help your body absorb more calcium. Conversely, when magnesium levels are low, calcium absorption suffers and muscle tension, cramps, fatigue and soreness can result, according to Shawn M. Talbot, Ph.D., author of "The Health Professional's Guide to Dietary Supplements." The combined effect of calcium and magnesium imbalance on muscle and nerve tissue can result in nerve and muscle irritability. If that imbalance occurs in your heart, irregular rhythms and palpitations can result.
Severe calcium deficiency can lead to a variety of health effects, including abnormal heart rate, convulsions and dementia. Calcium deficiency is common, affecting up to two out of three adults throughout the world, according to John D. Kirschmann, author of "Nutrition Almanac." As you age, your ability to absorb calcium diminishes. Excess calcium also occurs, particularly if you supplement heavily with calcium or use calcium supplements without taking additional magnesium to balance calcium levels in tissues. When this happens, calcium can accumulate in muscle tissue, including heart muscle, and lead to irregular contractions that you experience as a racing heart.
Magnesium reduces heart palpitations associated with recovery from thoracic surgery in some patients, according to a study published in the June 2011 issue of the "British Journal of Anesthesiology." In the study, doctors administered 5 mg of magnesium to participants during surgery and on each of the first two days following surgery. Results showed a 16.7 percent occurrence rate for supraventricular arrhythmia in the treatment group and 25 percent occurrence in a control group that did not receive the supplement. In participants at highest risk for arrhythmia, magnesium supplementation resulted in 11 percent occurrence compared to 53 percent in those in that subgroup who did not receive magnesium.