An electrolyte is a mineral in your body that carries electrical impulses. Electrolytes are essential for normal muscle function because they transmit electrical impulses from nerves. The heart consists of specialized muscles called myocytes that respond in unison to electrical impulses generated by specialized cells in upper right chamber of the heart, which is known as the sinus node. Improper levels of certain electrolytes can cause a condition called dysrhythmia or arrhythmia, which is an irregular heartbeat.
Potassium
Normal heart function depends upon tight regulation of potassium inside and outside of cells. The Institute of Medicine recommends that adults consume 4,700 milligrams of potassium per day to maintain a balance with the other electrolytes. Potassium crosses the cellular membranes, so the majority of potassium in your body remains inside cells. Because sodium, another electrolyte, stays in the fluid surrounding cells, the two electrolytes form an electrical and chemical gradient that conducts the electrical impulses. A low level of potassium -- a condition known as hypokalemia -- causes fatigue, muscle weakness, cramps and dysrhythmia. Hyperkalemia, or too much potassium, also causes fatigue, muscle weakness that can lead to temporary paralysis, and cardiac dysrhythmia that can lead to cardiac arrest.
Sodium
Although it is commonly thought of as a mineral you should avoid, your body needs sodium to function. Sodium not only conducts electrical impulses, but it also regulates the amount of fluid inside and outside of cells. Because sodium attracts water, too much sodium in the blood causes an increase in blood volume. In response to the increase in blood volume, your body increases blood pressure to propel the added blood volume through the body. This causes the heart to work harder, which can lead to a dysrhythmia.
Calcium
Your body needs calcium for many vital functions. The Linus Pauling Institute reports that 99 percent of calcium is found in your bones and teeth, and the remaining 1 percent stays in your blood. Although a small amount, the calcium in your blood is so crucial to life that your body regulates the levels by removing calcium from the bone material when necessary. Heart muscle cells contain tiny compartments that hold calcium ions. Electrical impulses from the sinus node stimulate the release of calcium ions from the internal structure, causing the heart muscle cell to contract. A low level of calcium, known as hypocalcemia, inhibits normal heart contractions and causes dysrhythmia, according to the Cleveland Clinic.
Magnesium
Magnesium is an essential mineral that supports over 300 biochemical reactions in the body and functions as an electrolyte by transmitting electrical impulses in muscle cells. While internal structures in the cell store calcium, magnesium remains in the fluid portion of the cell. When the electrical impulses stimulate the release of calcium, the magnesium ions react by producing tiny electrical charges that push the calcium back into the internal structure. This action allows the cell to relax. A decrease in magnesium levels allows calcium to remain in the fluid portion of the cell, interfering with the normal heart rhythm. Too much magnesium inhibits the release of calcium, causing dysrhythmia due to a weak, slow heartbeat.
References
- Institute of Medicine; Dietary Reference Intake Summary; 2004
- Linus Pauling Institute; Potassium; Victoria Drake; December 2010
- Cleveland Clinic; Management of Arrhythmias; August 2010
- Texas Heart Institute; Arrhythmia; June 2010
- Cleveland Clinic: Hypocalcemia
- Linus Pauling Institute; Calcium; Victoria Drake; October 2007
- Northwestern University: Magnesium
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