The physiological changes that began in middle adulthood intensify in late adulthood. Primarily a nuisance in middle adulthood, they begin to truly interfere with everyday functioning in late life. But it is important to distinguish between different stages of this last phase of life. Gerontologists, people who study aging, speak of the young-old and the old-old, meaning those in their sixties and early seventies and those over the age of seventy-five. Some also speak of the oldest old, those over eighty-five. The young-old, by and large, are still very vigorous. In the older age group, however, the decline in body functions can significantly constrict life activities.

What kind of bodily changes occur in late life? There is some belief that aging starts in the cells. There is decreased cell regeneration and deterioration in cell DNA and RNA. Brain cells also deteriorate, with decreased neurogenesis (new neuron growth) and general shrinkage of brain tissue. There is musculoskeletal deterioration, with continued loss of muscle mass and bone density. Thickening of the lens of the eye continues to reduce vision. Hearing, in particular, takes a hit, with 65 percent of people age eighty or above showing an inability to hear high-pitched sounds. Difficulties making sense of conversation can leave the elderly feeling socially isolated.

Additional changes take place in the gastrointestinal, cardiovascular, respiratory, and endocrine systems. Chronic diseases become much more common at this stage in life, particularly diabetes, hypertension, and arthritis. The news is not all bad, however. There are many lifestyle factors over which people have considerable control that can maximize health and well-being. Perhaps even to a greater extent than at younger ages, exercise, diet, positive mood, stimulating mental activities, and positive social relationships can promote optimal functioning.

Late adulthood, which can last up to thirty years (and beyond in some cases), is the last stage of life. Although this stage can cover many years, it still marks the closing of the life story. Adults at this stage must review their life as lived and come to some sort of emotional closure about how their life has unfolded. Adults in late life must also confront the unavoidable reality of mortality and hopefully come to accept the inevitability of death. People in this stage cope with numerous losses: physical vigor and sometimes health, roles and responsibilities of an earlier age, and loved ones who have died.

Luckily, older adults are often well-equipped emotionally to handle these daunting psychological challenges. Many studies show that psychological maturity continues to grow across the lifespan. In general, adults in late life have a more positive outlook, are less prone to negative emotional reactions, and are less egocentric than younger people. The storied wisdom of the old is both a function of life experience and a buffer against life experience.