Column: Reducing the risk of heart attack

The heart is a muscle that is expected to work day and night around the clock without any maintenance or overhaul for more than 70 years. Hopefully, you are one of those people who exercise to keep that heart healthy.

To understand the need for exercise for the heart, you need to understand the working of the heart itself. Visualize your own heart. There are four chambers in your heart, two upper or superior chambers called atria, both left and right sides, and two lower or inferior chambers called ventricles, also left and right sides.

The heart is for pumping blood, both oxygenated and deoxygenated types. Your muscles run on oxygenated blood, so this pumping operation depends on the capacity and workload of your pump.

Your lungs supply your heart with oxygenated blood. It enters the heart at the left atrium, which is the upper left chamber of your heart, by way of the pulmonary vein. Once in the heart, the blood is released by way of a valve into the lower, or inferior left ventricle chamber. Here the blood is forced out of the heart by way of the aorta into smaller vessels called arteries, then into arterioles and finally into the smallest units called capillaries. Two of the main aorta branches that become arteries also supply your heart with needed oxygenated blood. This is a simple description of how your heart delivers oxygenated blood from your lungs to the working muscles of your body.

Next, envision the return of that blood that has had the oxygen removed. This deoxygenated blood also contains waste products to be excreted from the body through sweat, urine, and the exhale phase of your breathing. The deoxygenated blood returns by way of the little veins called veinules, then into larger veins, and finally into the superior (upper) and inferior (lower) vena cava vessels, to empty into the right (upper) atrium of the heart. From here the blood is released by way of a valve into the right ventricle (lower) chamber of the heart and pumped out of the heart by way of the pulmonary vein back into the lungs for oxygenation. The whole process begins again.

Simply put, a program of exercise training (aerobic) has been shown to increase the capacity of the heart to pump blood. It involves a direct enlargement of the heart muscle, a more effective return of blood to the heart from the furthest peripheral tissues, increased blood volume and a slowing down of the heart rate allowing more time for the heart to fill. It all results in an increase in your work capacity and an increase in endurance.

Taken from another angle, reducing your resting heart rate from 85 beats per minute to 60 is what will occur after about six weeks of aerobic training. This will give your heart a savings of 1,500 pumps or beats per hour or more than a million beats per month. If you use your heart less, more efficiently, and with proper nourishment or fuel, it should last a lot longer.

The resulting cardiovascular efficiency may be the most important way that your exercise training reduces the risk of heart attack.

Jerry Vance is certified by the American Council on Exercise and teaches fitness at the Carson City Community Center and for the American Lung Association.