Some changes in the heart and blood vessels normally occur with age, but many other changes that are common with aging are due to modifiable factors that, if not treated, can lead to heart disease.
The heart has two sides. The right side pumps blood to the lungs to receive oxygen and get rid of carbon dioxide. The left side pumps oxygen-rich blood to the body.
Blood flows out of the heart through arteries, which branch out and get smaller and smaller as they go into the tissues. In the tissues, they become tiny capillaries.
Capillaries are where the blood gives up oxygen and nutrients to the tissues, and receives carbon dioxide and wastes back from the tissues. Then, the vessels begin to collect together into larger and larger veins, which return blood to the heart.
The heart has a natural pacemaker system that controls the 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.
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.
Heart changes cause the ECG of a normal, healthy older person to be slightly different than the ECG of a healthy younger adult. Abnormal rhythms (arrhythmias) such as atrial fibrillation are more common in older people. They may be caused by heart disease.
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.
Receptors called baroreceptors monitor the blood pressure and make changes to help maintain a fairly constant blood pressure when a person changes positions or activities. The baroreceptors become less sensitive with aging. This may explain why many older people have orthostatic hypotension, a condition in which the blood pressure falls when a person goes from lying or sitting to standing. This causes dizziness because there is less blood flow to the brain.
The capillary walls thicken slightly. This may cause a slightly slower rate of exchange of nutrients and wastes.
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 thickening of the heart muscle (hypertrophy). The other arteries also thicken and stiffen. In general, most elderly people experience a moderate increase in blood pressure.
The blood itself changes slightly with age. Normal aging causes a 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 their number and ability to fight off bacteria. This reduces the ability to resist infection.
EFFECT OF CHANGES
Under normal circumstances, the heart continues to adequately supply all parts of the body. However, an aging heart may be slightly less able to tolerate increased workloads, because changes reduce this extra pumping ability (reserve heart function).
Some of the things that can increase heart workload include:
Extreme physical exertion
Angina (chest pain caused by temporarily reduced blood flow to the heart muscle), shortness of breath with exertion, and heart attack can result from coronary artery disease.
Abnormal heart rhythms (arrhythmias) of various types can occur.
Anemia may occur, possibly related to malnutrition, chronic infections, blood loss from the gastrointestinal tract, or as a complication of other diseases or medications.
Arteriosclerosis (hardening of the arteries) is very common. Fatty plaque deposits inside the blood vessels cause them to narrow and can totally block blood vessels.
Congestive heart failure is also very common in the elderly. In people older than 75, congestive heart failure occurs 10 times more often than in younger adults.
You can help your circulatory system (heart and blood vessels). Heart disease risk factors that you have some control over include high blood pressure, cholesterol levels, diabetes, obesity, and smoking.
Eat a heart-healthy diet with reduced amounts of saturated fat and cholesterol, and control your weight. Follow your health care provider's recommendations for treating high blood pressure, high cholesterol, or diabetes. Minimize or stop smoking.
Exercise may help prevent obesity, and it helps people with diabetes control their blood sugar.
Exercise may help you maintain your abilities as much as possible and it reduces stress.
Have regular check-ups for your heart:
Have your blood pressure checked every year. If you have diabetes, heart disease, kidney problems, or certain other conditions, your blood pressure may need to be monitored more closely.
If your cholesterol level is normal, heave it rechecked every 5 years. If you have diabetes, heart disease, kidney problems, or certain other conditions, your cholesterol may need to be monitored more closely.
Moderate exercise is one of the best things you can do to keep your heart, and the rest of your body, healthy. Consult with your health care provider before beginning a new exercise program. Exercise moderately and within your capabilities, but do it regularly.
People who exercise usually have less body fat and smoke less than people who do not exercise. They also tend to have fewer blood pressure problems and less heart disease.
Schwartz JB, Zipes DP. Cardiovascular disease in the elderly. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa; Saunders Elsevier; 2007: chap 75.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.