Introduction

As the years pass, most people experience changes in the way their body functions. Some changes are obvious. For example, before age 50, most people begin to have trouble seeing objects that are up close. Other changes are hardly noticeable. For example, few people are aware that the kidneys may become less able to filter waste products out of the blood, because the kidneys usually continue to filter the blood well enough to avoid problems. Most people learn that their kidneys have aged only if a disorder develops.

See the figure Organs Affected by Aging.

Predicting how a particular person will age is hard, because each person ages at a different pace. In addition, how well a person takes care of the body influences how the person ages. Nonetheless, some changes are almost universal. Knowing what changes may be expected can help a person adjust to aging.