The type of exercise matters when it comes to brain aging, according to USC
researchers who investigated the connection between sedentary behavior and
dementia risk.
According to a recent study by USC and University of Arizona researchers,
those 60 and older who spend a lot of time watching TV or engaging in other
passive, sedentary activities may be more likely to acquire dementia.
Additionally, their study shown that the risk is reduced for individuals
who engage in activity while seated, such as reading or using a
computer.
On Monday, the study was released in the Proceedings of the National
Academy of Sciences publication. It also showed that even among those who
engaged in physical activity, the association between sedentary behavior and
the risk of dementia maintained.
The type of sedentary activity engaged in during free time, rather than the
amount of time spent sitting, affects dementia risk, according to research
author David Raichlen, professor of biological sciences and anthropology at
the USC Dornsife College of Letters, Arts, and Sciences.
When compared to using a computer or reading, watching TV entails less
muscular activity and energy use, the researcher said. And while studies
have shown that prolonged, uninterrupted sitting is associated with
decreased cerebral blood flow, the comparatively higher level of
intellectual stimulation experienced while using a computer may mitigate the
detrimental consequences of sitting.
Researchers looked into potential links between dementia in older adults
and sedentary leisure activity using self-reported data from the U.K.
Biobank, a sizable biomedical database with more than 500,000 participants
across the United Kingdom.
During the 2006–2010 baseline assessment period, more than 145,000 people
aged 60 and over who were all undiagnosed with dementia completed
touchscreen questionnaires to self-report information on their levels of
sedentary behavior.
The researchers analyzed hospital inpatient data to diagnose dementia on
average after almost 12 years of follow-up. 3,507 positive cases were
discovered.
Then, the researchers made adjustments for key demographics (such as age,
sex, race/ethnicity, and kind of job) and lifestyle factors (such as
exercise, alcohol and tobacco use, amount of sleep, and social interaction)
that could have an impact on brain health.
Effects of mental and physical activity on dementia risk
Even when the researchers took into consideration levels of physical
activity, the results remained unchanged. Even in those who are very
physically active, watching TV while relaxing was linked to a higher risk of
dementia, whereas using a computer while relaxing was linked to a lower risk
of dementia.
Gene Alexander, professor of psychology at the Evelyn F. McKnight Brain
Institute at the University of Arizona, said: "Although we know that
physical activity is good for our brain health, many of us think that if we
are just more physically active during the day, we can counter the negative
effects of time spent sitting."
Being more mentally active, such as when using computers, may be a key way
to help counter the increased risk of dementia related to more passive
sedentary behaviors, like watching TV, according to Alexander's findings,
which "suggest that the brain impacts of sitting during our leisure
activities are really separate from how physically active we are."
Understanding how sedentary behavior affects human health may result in
some improvements.
Raichlen said, "What we do when we're seated matters. When creating focused
public health interventions aiming at lowering the risk of neurodegenerative
disease from sedentary behaviors through positive behavior modification,
this understanding is essential.
