A study by scientists at Yale University has found that 45 percent of Americans over the age of 65 experienced improvements in their cognitive or physical functioning over a 12-year period.
The research, published in the medical journal Geriatrics, challenges the assumption that aging is an inevitable process of continuous decline. The study followed more than 11,000 older individuals for over a decade, tracking their health trajectories individually rather than looking only at the average age of the group.
Becca Levy, the lead author of the study, said in a statement that looking at the average of all participants shows a decline, but observing individual trajectories reveals a very different story. She said many people associate aging with an inevitable and continuous loss of physical and cognitive capacities.
Levy added that the researchers discovered improvement in old age is common, not rare, and it should be included in how the aging process is understood.
Cognitive and physical gains
The Yale team used data from the Health and Retirement Study, a large longitudinal survey that tracks the health and living conditions of older people in the United States. To evaluate cognitive function, the researchers used a global measure of mental performance.
For physical function, they measured walking speed. Geriatricians, medical doctors who specialise in the care of older adults, consider walking speed an especially useful variable because it is linked to disability, hospitalisation and mortality rates.
The results showed that up to 32 percent of the participants improved cognitively during the follow-up period, while 28 percent improved physically. In total, 45 percent experienced an improvement in at least one of the two areas during a period that lasted up to 12 years.
Impact of positive thinking
The researchers also analysed the beliefs the participants held about aging at the beginning of the observation period. They found that individuals who maintained a more positive view of getting older were more likely to improve their cognitive abilities and their walking speed.
This association remained even after the scientists accounted for other factors, including age, sex, educational level, chronic diseases, depression and the duration of the follow-up.
Levy proposed an explanation related to her theory of stereotype assimilation. From childhood, people absorb cultural messages about what it means to be old, such as the idea that older adults are fragile, slow, forgetful or unable to learn.
These ideas can eventually become part of a person's own perception of aging. According to previous studies by Levy, these negative stereotypes have been associated with worse outcomes for memory, walking speed and cardiovascular health.
Not just illness recovery
The observational study relies on longitudinal data, meaning it tracks the same people over time, but it does not prove that positive thinking directly causes a person to improve physically or retain their memory. The researchers noted the possibility of a two-way relationship, or that other factors might explain part of the link. A person who maintains good health might also develop a more positive perception of their own aging as a result.
However, the study does demonstrate that defining old age exclusively by a loss of memory, agility, strength or speed is overly simple.
The improvements were not limited to individuals who began the study with some level of difficulty. The gains were also observed in people who initially had normal cognitive or physical function, meaning the results were not simply a matter of sick people recovering from an illness.
The researchers said this opens up the possibility that aging might contain a much greater capacity for adaptation and reserve than is usually assumed. While this does not mean people can escape biological deterioration or that getting older has no consequences, it indicates that chronological age alone tells an incomplete story.
The findings suggest the right question might not be what will make us age better, but rather why some people continue to improve while others begin to deteriorate. Answering this question could change the way old age is understood.
