The changes begin much earlier than at age 65. Starting at about age 30, the body begins to lose about one percent of its function per year. The human body is so adaptable that most people continue to function relatively well despite the decrease in efficiency unless they suffer from disease. Even with chronic diseases such as arthritis, diabetes, or high blood pressure, many older adults remain mentally and physically active. The process of aging causes countless changes in the body which begin to affect an older person's physical and mental abilities.
Skin becomes thinner and drier.
The brain, the heart, the immune system, and other systems become less efficient. Cell loss in specific areas can lead to a reduction in the ability to smell, hear and feel sensation. There is a difference between being old and being sick. A changing body is a fundamental part of aging, but disease is not. Everybody will experience some problems as they age, and many problems can be cured or controlled medically.