Active elderly women scored better on tests of mental function than less active women, according to a new study led by researchers at the San Francisco VA Medical Center and the University of California, San Francisco.
Using actigraphs – wristwatch-like devices that continuously measure motion – the researchers recorded the daily daytime activity levels of 2,736 women over the course of three days. The women’s average age was 83.
Women whose actigraphs recorded 3,607 motions per day or more – not counting motions made during sleep – scored significantly better on standardized tests of cognition given than women who moved less. The cognitive tests were administered within several months of the motion studies.
The paper appears in the September, 2008 of the Journal of the American Geriatrics Society.
“More daytime movement was especially associated with better executive function, which is the ability to plan and execute daily tasks,” says lead author Deborah E. Barnes, PhD, MPH, a mental health researcher at SFVAMC and an assistant professor of psychiatry at UCSF. “The particular measure we used focused on being able to shift your attention back and forth – kind of like multitasking in daily life.”
All of the participants lived independently in their communities. None showed evidence of cognitive impairment.
Barnes notes that a number of past studies of the elderly have demonstrated an association between being active and being mentally alert, “but most of those studies are based on self-reporting, which raises the possibility that people aren’t necessarily being accurate about their own activity levels, especially if they have memory problems,” she says.
In contrast, actigraphs “objectively measure how much you move every minute of the day,” she says. “The degree of movement is captured as well, with bigger movements having greater weight than smaller movements.”
“Unfortunately,” she says, “we can’t translate actigraph data into its equivalent in walking, which is a limitation of the study.”
The study did not explore possible reasons for the association between increased movement and better cognition, says Barnes, “although,” she says, “there is now some really interesting evidence from a number of investigators that physical activity stimulates the growth of new neurons and new connections between neurons.”
Nonetheless, she says, “we cannot rule out the possibility that people who are more mentally alert are more likely to be physically active.”
To investigate the question of cause and effect, Barnes is currently conducting a longitudinal study in which older men and women who report memory problems “are being sent to the gym three days a week, to see if increasing their activity levels will also increase their levels of cognitive function.”
In the meantime, says Barnes, “it cannot hurt to be more active, whatever your age. It might help your overall health, and it might even be fun.”
Co-authors of the study are Terri Blackwell, MA, and Katie L. Stone, PhD, of California Pacific Medical Center Research Institute, San Francisco; Suzanne E. Goldman, PhD, APRN, of Vanderbilt University Medical Center, Nashville, TN; Teresa Hillier, MD, MS, of Oregon Health & Science University and Kaiser Permanente Center for Health Research, Portland, OR; and Kristine Yaffe, MD, of SFVAMC and UCSF.
The study was supported by funds from the National Institutes of Health, some of which were administered by the Northern California Institute for Research and Education.
NCIRE - the Veterans Health Research Institute - is the largest research institute associated with a VA medical center. Its mission is to improve the health and well-being of veterans and the general public by supporting a world-class biomedical research program conducted by the UCSF faculty at SFVAMC.
SFVAMC has the largest medical research program in the national VA system, with more than 200 research scientists, all of whom are faculty members at UCSF.
UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care.