Cardiovascular
System
The
main function of
this system is the internal transport of cells and dissolved materials,
including nutrients, wastes, and gases.
Differences
between cardiovascular functioning in older and younger persons have
been extensively quantified. However, interactions between age,
disease, and lifestyle are often overlooked. Whether the high
prevalence of cardiovascular disorders such as hypertension, coronary
artery disease, and heart failure is due to an aging process or whether
these disorders merely occur more frequently in elderly persons because
of a longer exposure to risk is not yet established. It is reasonable
to ascertain, however, that the capabilities of the cardiovascular
system gradually decline with age. |
|
Not
so fun fact:
The
25%
reduction in maximum cardiac output that occurs with aging is
completely due to the age-associated reduction in maximum heart rate. |
Fun
fact:
Older
people in good physical condition can match or exceed the aerobic
capacity of unconditioned younger people. |
|
Age-related
changes in the
blood include a decrease in the volume of packed red blood cells or
constriction or blockage of peripheral veins by a blood clot. Also,
there might be pooling of blood in the veins in the legs because valves
are not working effectively.
Age-related
changes in the
heart include a reduction in maximum cardiac output, changes in the
activities of nodal and conductive fibers, a reduction in the
elasticity of the heart’s fibrous tissues, progressive
atherosclerosis (fatty buildup or plaques) that can restrict coronary
circulation, and replacement of damaged cardiac muscle fibers by scar
tissue.
Age-related
changes in
blood vessels are often related to arteriosclerosis, a thickening and
toughening of arterial walls in which the walls become less tolerant of
sudden increases in pressure.
Aging affects
aerobic
capacity and cardiovascular performance during exercise. Peak exercise
capacity and peak oxygen consumption decrease with age, but there is
great variation from one individual to another. Aerobic capacity
decreases by 50% between ages 20 and 80.
Physical
conditioning
appears to lessen the vascular stiffening associated with aging since
stiffening is increased by only about half as much in endurance-trained
elderly persons as compared to sedentary ones. Exercise can also
improve the aerobic capacity of older persons by increasing cardiac
output and oxygen utilization. |
