During late adulthood, individual differences in physical capacities are greater than at any other time in life. A complex combination of genetic and environmental factors combine to determine longevity. More rapid declines occur in the functioning of the brain and autonomic nervous system, sensory systems, cardiovascular and respiratory systems, and immune system, and age becomes more outwardly apparent. Despite these declines, older adults are optimistic about their health. A healthy diet, appropriate exercise and an active, stimulating lifestyle continue to contribute to quality and length of life, and sexual enjoyment can be maintained well into late adulthood. Still, many illnesses become more common as age advances, and dementia rises in old age. The most common form of dementia is Alzheimer's disease. In the United States, Alzheimer's is a leading cause of death in late adulthood.

While cognitive declines outweigh advances in late adulthood, high- functioning elders optimize their capacities by becoming more selective in their pursuits and finding new ways to compensate for declines. Memory declines primarily in deliberate processing and prospective memory. These declines affect language production, and hearing loss contributes to difficulties in receptive language. While problem solving becomes less effective, older adults are adept at making quick health-related decisions. And although wisdom is predicted more by life experience than by age, active, respected elders often demonstrate it.

As in earlier age periods, an active mental life predicts maintenance of mental abilities well into old age. Health status also becomes a predictor of cognitive functioning. Terminal decline, or a steady, marked decline in cognitive functioning, indicates that death will soon occur. Older adults benefit greatly from training in cognitive skills, and more attention is being given to their continuing education. Many types of programs exist, combining education and meaningful experiences to enrich the lives of senior citizens.