Findings may lead to increased mobility, independence for elderly
BOSTON--Positive words picked up the walking pace of older persons, according to a Boston study that blames a pessimistic outlook on aging for the slower treads typical of many older people. Walking speed can predict future health and independence in older persons.
The research is published in the November issue of the Journal of the American Geriatrics Society.
"What's surprising is that the way in which older people view older people can significantly affect their physical function," says lead author Jeffrey Hausdorff PhD, a researcher at Beth Israel Deaconess Medical Center. "The clinical ramifications of this finding need to be studied further, but clearly if we as a society could work to minimize the negative stereotypes about aging and being old, we could likely improve physical function and independence as well as psychological well-being in the fastest growing segment of the American population."
For the study, 47 healthy men and women with an average age of 70 were assigned randomly to one of two groups. Individuals in each group played a 30-minute computer game that flashed words associated with aging stereotypes on the screen. The words flashed by too quickly to read, but slow enough to perceive subconsciously. Those who received the subliminally delivered positive words, such as "wise," "astute," and "accomplished," subsequently increased their walking speeds by 9 percent. Those who received negative words about aging, such as "senile," "dependent," and "diseased," maintained the same walking speed.
A person's usual walking speed is a common measure of overall fitness and physical function and has been correlated to the short-term risk of nursing home admission and death in older people. Studies by others have shown that walking speed decreases 9 percent to 30 percent with advancing age.
"While many factors may contribute to this decline, we did not expect to see this large of an effect of the stereotypes of aging on gait speed and on the age-related decline in walking performance," says Hausdorff, also an assistant professor of medicine at Harvard Medical School.
The 9 percent gait improvement reported in this study is also similar to the gains reported in other studies of the effects of 12 weeks of strength training on walking in older persons.
For his studies of gait, Hausdorff has developed special wafer-thin shoe inserts with recording devices in attached ankle straps. This way, he can measure natural stride-to-stride variations. Typically, the time a foot spends in the air for each step, known as "swing time," decreases with aging. But in this study, the positive steretypes of aging also improved this aspect of walking.
For this study, Hausdorff teamed up with social psychologist Becca Levy PhD, who first developed this method of triggering aging stereotypes to examine their effects on thinking and behavior when she was a graduate student at Harvard College. Levy conducted the gait study as a postdoctoral fellow at Harvard Medical School. Now she is an assistant professor at Yale University Medical School. In other work, Levy has found that stereotypes of aging also affect memory, self confidence, handwriting and even the will to live in older people.
"Individuals tend to acquire negative stereotypes about aging as young as 3," Levy says. "When individuals become older, these stereotypes become relevant to themselves. Unlike stereotypes of race or sex, stereotypes of aging become directly relevant to everyone who lives a normal lifespan. This latest study with gait demonstrates that the negative stereotypes of aging that exist in our culture may have numerous implications for everyone who is already or who will one day become old."
The authors plan to continue studying the unanticipated powerful connection between subconscious perceptions about aging and physical performance. They believe this information eventually may be used to enhance mobility and partially reverse age-related changes in functional performance.
In related work, Hausdorff has been studying stride-to-strike fluctuations in gait rhythm and the effects of aging and disease. He has found that healthy gaits fluctuate with a "fractal-like" pattern, documented a break down in the fractal nature of elderly gaits, and correlated gait dynamics with disease severity in people with neurodegenerative diseases, such as Huntington's and Parkinson's.
The study was funded by the National Institute of Aging and the National Institute of Mental Health. Beth Israel Deaconess Medical Center is a major clinical, research and teaching affiliate of Harvard Medical School and a founding member of CareGroup Healthcare System.
Media contacts for embargoed news:
-- Jeffrey Hausdorff PhD, gerontology, BI-Deaconess, 617-667-4554, jhausdor@caregroup.harvard.edu
-- Becca Levy PhD, epidemiology and public health, Yale, 203-785-2869, becca.levy@yale.edu
-- Carol Cruzan Morton or Bill Schaller, communications, BI-Deaconess, 617-667-4431, cmorton@caregroup.harvard.edu or wschalle@caregroup.harvard.edu
Journal
Journal of the American Geriatrics Society