Throughout a person's day, their heart beats over 100,000 times and changes pace and rate based on what the person is doing. Also, over time there fatty deposits build up in arteries making it more difficult for the heart to pump blood. After years of constant adjusting beating and adjusting, the heart starts to have trouble pumping blood throughout the body.

As people age, they are less able and less likely to do vigorous exercise. Exercising is healthy for the heart, so those who continue to exercise into their old age are less likely to experience heart problems than others their age, but are still more likely to have heart problems than when they were younger. Also, as a person ages, their heart beats more slowly. Those in their 20s have an average heart rate of 180 to 200 beats per minute whereas an 80 year old has an average heart rate of 145 beats per minute. The slower heart rate is due to fatty buildup as well as other problems that occur in the cardiovascular system as the body ages.

Arteries harden and become inflexible as the body gets older. Because of this, the heart has to compensate by increasing the blood pressure, which, besides causing problems such as aneurysms, makes the heart have to work harder.