First the blood vessels. The walls of the arteries stiffen with age. And the largest blood vessel in the body, the aorta, gets longer and dilates as you get older. These developments can occur just from aging and in the absence of significant atherosclerosis in the vessels. They are secondary to changes that are happening to collagen and elastin and to deposits of calcium. The actual tonus (or tension) of the arteries also increases with the progressive thickening of the layer of the arterial wall that is present under the inside lining. These changes may contribute to high blood pressure and damage to the arteries, which encourage atherosclerosis. (High blood pressure and atherosclerosis ultimately adversely affect circulation to the brain and the rest of the body, as well as the healthful functioning of the heart.) But blood pressure does not have to rise substantially just because of age. Many other factors are involved. And many medications are now available to reduce blood pressure.
Several structural changes take place in the heart itself. The heart may enlarge, especially the upper chamber on the left side. The heart muscle may change as a result of the size of the muscle cells increasing or becoming replaced with fibrous tissue.
Functional changes, frequently referred to as “pump performance,” occur. The rate at which the heart fills with blood decreases steadily throughout adult life, and in the elderly the rate may slow to half that of a young adult. The way the heart muscle contracts is related to structural changes within the healthy heart itself and to the increasing resistance of the arteries to the flow of blood.
The good news is that some changes of aging that appear inevitable may be delayed or modified by changes in lifestyle and diet. I’ll discuss this more later, but I’ll make my first attack on salt here. It can be poison to many of us.
