Cardiovascular System (Heart and Blood Vessels)

The cardiovascular system includes the heart which pumps the blood throughout the body and the network of blood vessels through which the blood is transported. In healthy people, the changes that normally occur in the cardiovascular system with aging do not significantly limit the normal work capacity of the heart. Most of the changes that cause clinically significant declines in cardiovascular function are the result of disease.

Heart Muscle

As we age, the heart muscle becomes slightly stiffer and may increase slightly in size. Despite this slight increase in heart size, the amount of blood the chamber can hold may actually decrease because the heart wall thickens. The maximum heart rate (the highest rate at which your heart can pump) decreases even among the most fit athlete. However, the resting heart rate and the cardiac output (amount of blood pumped over a period of time) do not change. In response to stress or exertion, older adults compensate for their lower maximum heart rate by increasing their stroke volume (i.e., amount of blood pumped with each contraction of the heart) to maintain cardiac output. Among older adults it takes longer for the heart rate and blood pressure to return to normal resting levels following stress.

Aorta and Other Blood Vessels

Our blood vessels, including the aorta and other arteries also become stiffer and are less responsive to hormones that relax the blood vessel walls. The stiffening of blood vessels contributes to the increasing systolic blood pressure with aging observed in most cultures. In Western countries, systolic blood pressure tends to increase throughout a persons life span, while diastolic blood pressure rises until age 60 and then levels off. Nearly 50% of older adults have chronic hypertension. Increases in systolic blood pressure do not occur in many nonindustrialized societies which suggests that risk for hypertension is affected by environmental factors such as diet and lifestyle as well as heredity.

Heart rate, Murmurs, and Hypotension

Our heart rate may be slightly slower as we grow older due to a loss in the number of pacemaker cells. The electrical pathways may develop fibrous tissue and fat deposits that can make abnormal heart rythms more common. Shifts in the circulation of blood to various organs can also change-- the blood flow to the kidneys may decrease by 50 percent and to the brain by 15 to 20 percent. Heart murmurs are also common with age because our heart valves become less flexible and calcium deposits build up.

Finally, the organs which monitor the blood pressure and adjust your blood pressure when you change position become less sensitive with aging. This can cause orthostatic hypotension (a condition where the blood pressure falls when you go from lying or sitting to standing) and cause dizziness when you change position. Therefore, if you (or your client) gets dizzy in the morning when getting out of bed, you should change position more slowly-- sit for a few minutes before standing up.