Your bones contain 99 percent of all the calcium in your body. The 1 percent left in the blood and fluids surrounding the cells performs functions so vital to life that your body will break down bone just to maintain the required concentration, as described by the Linus Pauling Institute. In addition to its role in bone strength, calcium helps regulate muscle contractions, making it important to your heart's health.
Heart Contractions
The heart consists of millions of tiny individual muscle cells known as myocytes. A group of specialized cells in the upper right chamber of the heart, known as the sinus node, produces electrical impulses that cause the heart to pump. These electrical impulses stimulate the individual muscle cells to contract simultaneously. The muscle contraction also requires ions, including sodium, potassium, calcium and magnesium. The heart's ability to contract as well as the length, strength and duration of the contraction, relies upon the exchange of these ions.
Calcium in Contractions
The sarcoplasmic reticulum, or SR, is a cellular structure that stores calcium within each myocyte. As the heart muscle contracts, calcium ions flow from the SR into the cells. The calcium ions help to increase the duration of the heart contraction. Following the contraction, the calcium flows back into the SR, allowing the heart muscle to relax while awaiting the next contraction.
Calcium in Blood Vessels
Calcium also regulates the constriction and relaxation of blood vessels to help keep blood flowing through the body. Blood vessel relaxation, known as vasodilation, affects your blood pressure, which is the measure of the force of blood against the walls of the blood vessels. High blood pressure is defined by the National Heart Lung and Blood Institute as a systolic reading of 140 or more and a diastolic reading of 90 or higher. High blood pressure contributes to heart disease, so maintaining healthy blood vessels is important for overall heart health.
Calcium Intake
Consume adequate amounts of calcium for both healthy bones and a healthy heart. The National Institute of Medicine Food and Nutrition Board recommends that adults consume 1,000 to 1,200 mg per day. Inadequate calcium intake can cause a decrease in your blood calcium levels, which will cause the parathyroid gland to produce parathyroid hormone. This hormone triggers vitamin D to convert to its active form, known as calcitriol, to stimulate the digestive tract to increase calcium absorption.
Heart Health
Doctors encourage adults, especially as they get older, to take calcium supplements to help avoid the onset of osteoporosis, or a weakening of the bones. Increasing your calcium intake through your diet or by taking supplements may also help to decrease blood pressure, as described by the Linus Pauling Institute. The DASH diet, which stands for Dietary Approaches to Stop Hypertension, outlines a heart-healthy eating plan to lower blood pressure by emphasizing the consumption of low-fat foods rich in fruits, vegetables and low-fat dairy products to boost calcium levels.
References
- Linus Pauling Institute: Calcium
- National Heart Lung and Blood Institute: High Blood Pressure
- American Heart Association: "Circulation Research"; Cardiac Intracellular Calcium Release Channels; Andrew R. Marks; 2000
- National Institute of Medicine: Food and Nutrition Board: Dietary Reference Intakes
- National Heart Lung and Blood Institute: Your Guide To Lowering Your Blood Pressure with DASH
