Being in good physical shape may help
preserve people's thinking and memory skills, according to a new study. Researchers
made this discovery by mapping participants' physical fitness against the
number of errors they made on a range of cognitive tests over time.
They found, for instance, that 80-year-olds
who were at one point approximately twice as fit as their peers made about 25%
fewer errors on a test of memory and concentration.
"This study shows that your
cardiovascular fitness at one point in time can predict how well your memory
may function in the future," said Carrington Wendell. Wendell led the
study and is a researcher with the Bethesda, Maryland-based National Institute
A growing body of research has hinted at a
relationship between exercise and cognitive decline in old age. But prior
studies typically measured physical fitness by asking people to recall how
often they exercised in the past. "Participants are not always the best
historians," Wendell told Reuters Health.
Out of breath
For the new study, 1 400 men and women were
asked to walk, jog or run on a treadmill until they were out of breath. A
machine measured the amount of oxygen participants breathed in and carbon
dioxide breathed out to calculate each person's so-called VO2 max.
"VO2 max is the maximal amount of
oxygen used by your lungs during one minute of strenuous exercise. Generally,
the more oxygen your lungs are able to use, the healthier you are,"
added that researchers working on similar studies in the past may not have
chosen VO2 max as a measurement because it is time-intensive and can be
This relatively objective measure of
fitness is "a particular strength of the study," said Stewart Longman
in an email to Reuters Health. Longman is a rehabilitation psychologist at the
University of Calgary in Canada and was not involved with the current research.
Participants were assessed when they were
anywhere from 19 to 94 years old, as part of a study called the Baltimore
Longitudinal Study of Ageing.
The researchers followed each person for an
average of seven years after the treadmill test. All participants took a memory
test and followed up with the study team once, but less than half made a second
visit to complete additional cognitive tests, the researchers wrote in The
Journals of Gerontology: Series A.
Relationship between exercise and brain
"In terms of the level of evidence,
this is an observational study," said Deborah Barnes. The study can show
physical fitness is associated with better thinking and memory skills, but not
prove it's responsible. Barnes, a psychiatry researcher at the University of
California, San Francisco, has studied exercise and cognitive ability but did
not participate in the current study.
"Ten years ago, people were more sceptical
about a relationship between exercise and the brain, but studies like this
helps us realise that exercise has profound effects," Barnes told Reuters
Health. "The key message here is that being more physically fit may help
someone keep their memory sharper with age," she said. Wendell and her
colleagues were not trying to determine why exercise might help prevent memory
decline in their study. But they said past research suggests exercise may have
a direct effect on signal-sending cells in the brain and other components of
brain structure and function. Researchers agreed future work on the subject
still needs to be done.
"It would have been nice to have
additional VO2 max measurements, instead of only at the beginning," Barnes
said. With this extra data, researchers could have looked more closely at correlations
between changes in aerobic fitness and cognitive performance over time. But the
real issue may be what to do with the new information.
"The challenge now is how do we get
people to go out and exercise?" Barnes said. "We know exercise is
good for us, now how do we do it every day?"