The CVS consists of the heart muscle and all the blood vessels the heart uses to pump blood throughout the body. The CVS circulates blood to transport oxygen and nutrition to all the body’s cells, and moves carbon dioxide and cellular waste to the organs that can clean those things out. It also is the transportation system for hormones and messenger proteins that need delivery to various parts of the body, as well as moving white blood cells to areas where the immune system may be fighting infections or even cancer cells. The heart itself has two sides: the right heart, which takes oxygen-low blood from the body and pumps it to the lungs, where more O2 is absorbed and CO2 is moved out of the blood; and the left heart, which receives blood from the lungs and sends it out to the rest of the body. Blood leaves the heart and enters arteries that head everywhere in the body, including the heart itself. From arteries, the blood enters smaller arteries called arterioles, then even smaller blood vessels called capillaries that are small enough for nutrition and O2 to seep right into the cells around them. From there, the blood moves into slightly larger but less muscular vessels called venuoles as it turns back towards the heart, eventually moving into the larger veins before arriving back in the heart. Aging affects all of these structures, as well as the special electrical system that coordinates our regular heart rhythm of our heart. So, what happens to the CVS as we age normally?
- In the heart’s pacemaker system that controls the heart rate, some of the nerves develop thickened tissue and fatty buildup, which can lead to a general slowing of the heart rate over time.
- The heart muscle itself can gradually become a little thicker, which can diminish the size of the chambers of the heart and can also slow the ability of the heart to fill fully.
- The electrical heart tracing or ECG in healthy older adults changes compared to that of younger adults as the heart changes over time (likely related the slowing of the heart rate described under 1 above). The development of different kinds of heart disease can sometimes lead to very abnormal heart rhythms, such as Atrial Fibrillation, which is much more common in older adults.
- Other normal changes to the heart include deposits of the aging pigment lipofuscin in the heart muscle, slight degeneration of heart muscle cells, stiffening and thickening of the valves inside the heart that control direction of blood flow, and the development of a slight heart murmur as a result of the stiff heart valves.
- Baroreceptors (see Why You Should Love Your Baroreceptors) become less sensitive with aging, which can contribute to sudden drops in blood pressure when you move from reclining to sitting or standing, and general dizziness.
- The walls of the smallest blood vessels, the capillaries, can get thicker with aging, which could contribute to slower exchange of fuel and waste into and out of our body’s tissues.
- Both the main artery leaving the left heart, the aorta, and other arteries in the body start to have changes in their connective tissue layers. This can lead to the vessels becoming stiff and less flexible, which in turn can make the heart work harder. This can lead to heart thickening mentioned in #2 above, and also contributes to the development of high blood pressure seen in most older adults.
- Although related to many genetic and lifestyle many factors, inflammation and fatty deposits can start to develop in the walls of the arteries of the CVS, as early as teenage years, which can eventually contribute blockages to blood flow and to many serious problems of the heart, including heart attacks and strokes.
- High blood pressure and orthostatic hypotension, mentioned above, very commonly develop with older age. Hypertension can contribute to many of the other problems listed below, and orthostatic hypotension could contribute to dizziness and falling as we age.
- Arteriosclerosis, or hardening of the arteries (mentioned in #8 above), in which fatty plaque deposits inside the blood vessels cause them to narrow and which can totally block blood vessels.
- The thickening of the heart muscle (described in #2 above) can lead to Coronary Artery Disease when the arteries that supply the heart with blood are affected. This can lead to angina, or heart pains, shortness of breath, and, more seriously, heart attacks.
- Irregular heart rhythms, known as arrhythmias, which can cause uncomfortable symptoms and even cause the heart to stop working altogether in their extremes.
- Congestive heart failure, very common in the older adults, and can result from a combination of many factors, including heart muscle thickening, heart valve stiffening, and heart attacks.
- Transient ischemic attacks or strokes can occur if blood flow to the brain is disrupted, as a result of arteriosclerosis, arrhythmias, and other factors in the CVS.