As an expanding body of work continues to confirm
links between exercise and improved brain function in
older adults, a new study by researchers at the
University of Illinois at Urbana-Champaign and Vrije
Universiteit in Amsterdam suggests similar
improvements among younger populations as well.
“Physical activity may be beneficial to cognition
during early and middle periods of the human lifespan
and may continue to protect against age-related loss
of cognitive function during older adulthood,” said
Charles H. Hillman, a U. of I. professor of
kinesiology and of community health and the lead
author of the study, published in the current edition
of the journal Health Psychology.
Hillman said the findings support the need to promote
the benefits of regular exercise across the lifespan,
beginning in childhood. And, he said, more research is
needed to gain a better understanding of the
relationship between physical activity and cognition
for people of all ages.
“It is important to begin studying individuals during
early adulthood, and especially childhood, as early
intervention may be more beneficial. That is, why wait
until individuals are older and have been sedentary to
intervene? Why not demonstrate the prophylactic
effects of exercise on cognition at an earlier age, if
there is indeed an effect?”
Hillman noted that most previous research to date
indicating positive relationships between physical
activity and cognitive function has been focused
primarily on older populations. The current study
considered data collected by Hillman’s Dutch
colleagues from 241 people aged 15-71 living in the
greater Amsterdam area. Participants reported their
physical-activity behavior and completed a series of
tests designed to indicate task-performance
capabilities.
The tasks, which measured subjects’ reaction time and
response accuracy when presented with congruent and
incongruent visual patterns, involve cognitive
processes known as executive control function (ECF).
ECF, Hillman said, “refers to a subset of processes –
planning, scheduling, working memory, inhibition, task
coordination etc. – involved in the intentional
component of environmental interaction.” In other
words, he said, while carrying out these activities,
“the individual cannot go on ‘autopilot.’ Further, the
task never habituates, meaning that each time the task
is presented, it requires control.”
After controlling for gender and IQ – factors related
to physical activity participation or cognitive
function – the researchers documented slower reaction
time among older compared with younger subjects, and
improved (faster) reaction time with increased
physical-activity participation. Among older
participants, those who indicated they were physically
active demonstrated improved task performance – in
reaction time and response accuracy.
Physically active younger participants registered
improved reaction times. However, Hillman said, there
was no significant correlation between physical
activity and response accuracy among that group.
In general, he noted, the study results supported
conclusions of previous research by U. of I.
psychology and neuroscience professor Arthur F. Kramer
and colleagues linking physical activity to improved
performance on tasks with large executive components.
But Hillman’s team also observed improvement on tasks
with small executive components, “indicating a general
relationship of physical activity to cognitive
performance that is selectively larger for ECF.”
Hillman described tasks with large executive control
components as those requiring “inhibition of habitual
responses, such as stepping on the brake when the
light changes from red to green because a cyclist
jumps out in front of the car.”
Another example, he said, involves “the management of
interference within an environment – for example,
detecting a street sign amid a visually confusing
environment.” Greater levels of ECF are also present
when “switching between cognitive tasks,” or, in
simple, everyday terms – multitasking.
Among the study’s older physically active participants
there was a “disproportionately larger influence of
physical activity on tasks requiring greater amounts
of executive control.” No similar relationship was
observed among younger subjects.
In the end, Hillman said the researchers do not know
whether physical activity protects against cognitive
loss during younger periods of the lifespan or if it
promotes better cognitive function.
“Regardless,” he said, “the importance is the same.
Physical activity is related to better cognitive
health and effective functioning across the lifespan.”
Co-authors of the study with Hillman are U. of I.
kinesiology and community health professor Robert W.
Motl and U. of I. graduate student Matthew B. Pontifex,
and, at Vrije Universiteit, biological psychology
professors Dorret I. Boomsma, Eco J.C. de Geus and
Danielle Posthuma, and graduate student Janine H.
Stubbe.
