Calcium and magnesium are both essential minerals that function as electrolytes within the body. This means they help transmit electrical impulses between nerve and muscle cells, and also help balance the amount of fluid inside and outside of cells. Calcium and magnesium work closely together, and the level of each must remain in balance with the other to regulate blood pressure and maintain a steady heartbeat. Your body can, however, absorb calcium without magnesium.
Calcium and magnesium play a vital role in regulating your heartbeat. Cells, including heart muscle cells, contain calcium inside of a specialized structure of the cell. The cell responds to electrical impulses by releasing calcium ions into the fluid portion of the cell therefore stimulating the cell to contract. The magnesium ions in the fluid portion of the cell produce electrical charges that force the calcium back into the cell structure, which triggers the cell to relax. Although magnesium does not affect the absorption of calcium in the body, it does control the transport of calcium across cell membranes. You must maintain a balance between calcium and magnesium to maintain a normal heartbeat and regulate your blood pressure. The best way to do this is to maintain the recommended daily intake of both calcium and magnesium.
The Institute of Medicine recommends that adults age 19 and older consume at least 1,000 mg of calcium per day. As you age, your body begins to break down bone mass faster than it can rebuild it, so women age 51 and older and men over age 70 should increase their intake to 1,200 mg of calcium per day. Vitamin D facilitates the absorption of calcium. Without enough vitamin D, your body cannot efficiently absorb calcium. To ensure proper calcium absorption, adults up to age 70 need at least 15 micrograms, or mcg, of vitamin D per day, while those over age 70 need at least 20 micrograms per day.
Like calcium, the majority of the magnesium in your body remains in the bones to support their strength. The Linus Pauling Institute reports that approximately 26 percent of the body's magnesium can be found in muscle cells. Because male bodies usually contain more muscle mass, they require a higher intake of magnesium per day than females. Adult men ages 19 to 30 need 400 mg of magnesium per day, while men 31 or older need 420 mg per day. Women between the ages of 19 and 30 should intake 310 mg of magnesium per day, while those over 30 should increase their intake to 320 mg per day. Vitamin D might also play a small role in the absorption of magnesium, but a lack of vitamin D does not affect magnesium levels as much as calcium levels.
An imbalance between the amount of calcium and magnesium in the body can occur due to many factors. Failing to take enough calcium, or enough vitamin D to support calcium absorption, can cause a calcium deficiency. In addition, the thyroid gland produces the hormone calcitonin, which regulates the concentration of calcium in the blood. Thyroid disease can cause the production of too much calcitonin, which decreases the amount of calcium in the body. When your body contains too much magnesium and not enough calcium, muscle contractions weaken. This causes the heart to beat less forcefully, with longer periods of relaxation between beats, leading to an irregular heartbeat.