Aging Changes in the Heart and Blood Vessels

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Aging changes

Heart

• Normal changes in the heart include deposits of the "aging pigment," lipofuscin. The heart muscle cells degenerate slightly. The valves inside the heart, which control the direction of blood flow, thicken and become stiffer. A heart murmur caused by valve stiffness is fairly common in the elderly.
• The heart has a natural pacemaker system that controls heartbeat. Some of the pathways of this system may develop fibrous tissue and fat deposits. The natural pacemaker (the SA node) loses some of its cells. These changes may result in a slightly slower heart rate.
• Heart changes cause the ECG of a normal, healthy aged person to be slightly different than the ECG of a healthy younger adult. Abnormal rhythms (arrhythmias) such as atrial fibrillation are common in older people, which may be caused by heart disease.
• A slight increase in the size of the heart, especially the left ventricle, is not uncommon. The heart wall thickens, so the amount of blood that the chamber can hold may actually decrease despite the increased overall heart size. The heart may fill more slowly.

Blood vessels

• The main artery from the heart (aorta) becomes thicker, stiffer, and less flexible. This is probably related to changes in the connective tissue of the blood vessel wall. This makes the blood pressure higher and makes the heart work harder, which may lead to hypertrophy (thickening of the heart muscle). The other arteries also thicken and stiffen. Overall, most elderly people experience a moderate increase in blood pressure.
• Receptors, called baroreceptors, monitor the blood pressure and make changes to help you maintain a fairly constant blood pressure when you change positions or activities. The baroreceptors become less sensitive with aging. This may explain the relatively common finding of orthostatic hypotension, a condition in which the blood pressure falls when you go from lying or sitting to standing, which may result in dizziness when you stand up.
• The wall of the capillaries thickens slightly. This may cause a slightly slower rate of exchange of nutrients and wastes.

Blood

• The blood itself changes slightly with age. Aging causes a normal reduction in total body water. As part of this, there is less fluid in the bloodstream, so blood volume decreases.
• The number of red blood cells (and correspondingly, the hemoglobin and hematocrit levels) are reduced. This contributes to fatigue. Most of the white blood cells stay at the same levels, although certain white blood cells important to immunity (lymphocytes) decrease in number and ability to fight off bacteria. This reduces the ability to resist infection.