Walk, Jog or Dance: It’s All Good for the Aging Brain
By Gretchen Reynolds
More people are living longer these days, but the good news comes
shadowed by the possible increase in cases of agerelated mental decline. By
some estimates, the global incidence of dementia will more than triple in the
next 35 years. That grim prospect is what makes a study published in March in
The Journal of Alzheimer’s Disease so encouraging: It turns out that regular
walking, cycling, swimming, dancing and even gardening may substantially
reduce the risk of Alzheimer’s.
Exercise has long been linked to better mental capacity in older people.
Little research, however, has tracked individuals over years, while also
including actual brain scans. So for the new study, researchers at the
University of California, Los Angeles, and other institutions analyzed data
produced by the Cardiovascular Health Study, begun in 1989, which has
evaluated almost 6,000 older men and women. The subjects complete medical
and cognitive tests, fill out questionnaires about their lives and physical
activities and receive M.R.I. scans of their brains. Looking at 10 years of data
from nearly 900 participants who were at least 65 upon entering the study, the
researchers first determined who was cognitively impaired, based on their
cognitive assessments. Next they estimated the number of calories burned
through weekly exercise, based on the participants’ questionnaires.
The scans showed that the top quartile of active individuals proved to
have substantially more gray matter, compared with their peers, in those parts
of the brain related to memory and higherlevel thinking. More gray matter,
which consists mostly of neurons, is generally equated with greater brain
health. At the same time, those whose physical activity increased over a five year period — though these cases were few — showed notable increases in
graymatter volume in those same parts of their brains. And, perhaps most
meaningful, people who had more gray matter correlated with physical activity
also had 50 percent less risk five years later of having experienced memory
decline or of having developed Alzheimer’s.
“For the purposes of brain health, it looks like it’s a very good idea to stay
as physically active as possible,” says Cyrus Raji, a senior radiology resident at
U.C.L.A., who led the study. He points out that “physical activity” is an elastic
term in this study: It includes walking, jogging and moderate cycling as well as
gardening, ballroom dancing and other calorieburning recreational pursuits.
Dr. Raji said he hopes that further research might show whether this caloric
expenditure is remodeling the brain, perhaps by reducing inflammation or
vascular diseases.
The ideal amount and type of activity for staving off memory loss is
unknown, he says, although even the most avid exercisers in this group were
generally cycling or dancing only a few times a week. Still, the takeaway is that
physical activity might change aging’s arc. “If we want to live a long time but
also keep our memories, our basic selves, intact, keep moving,” Dr. Raji says.
