TV Lover? Think Twice! Study Says Watching TV May Slow the Brain

Watching TV is not as good as it seems, especially for young adults.

In a study published at JAMA Psychiatry, it was revealed that watching TV and having low physical activity during early adulthood have a negative impact to the brain and its cognitive functions later in life.

According to the study, those people with high television viewing and low physical activity were more likely to have poor cognitive performance than those with low television viewing and high physical activity.

In order to reach this conclusion, the Tina D. Hoang, M.S.P.H., of the Northern California Institute for Research and Education at the Veterans Affairs Medical Center, and co- researchers assessed 3,247 adults aged 18 to 30-years old who were enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study.

The researchers collected data about the participants' TV viewing and physical activity through a validated questionnaire which the participants answered every 2-5 years in a span of 25 years from 1985-2011.

High TV viewing was defined as watching TV for more than three hours a day in more than two-thirds of the visits, while low-physical activity was defined as activity levels that were below the "lower, sex-specific baseline quartile" for more than two-thirds of the study.

Moreover, after the 25 year duration of collecting data, the researchers then asked the participants to complete a series of cognitive tests that included the Digit Symbol Substitution Test (DSST), Stroop Test, and Rey Auditory Verbal Learning Test (RAVLT), which measures processing speed, executive function, and verbal memory, respectively.

The study found that those participants who had high TV viewing and low physical activity had the worst results of the DSST and Stroop test, although not in the RAVLT, thereby concluding that high TV viewing and low physical activity is associated with slower processing speeds and poorer executive function, but not with the verbal memory.

"High television viewing and low physical activity in early adulthood were associated with worse midlife executive function and processing speed. This is one of the first studies to demonstrate that these risk behaviors may be critical targets for prevention of cognitive aging even before middle age," the researchers concluded in the study.

Nonetheless, according to Medical News Today (MNT), the researchers admitted that there are limitations in the study, especially with the participants' drop-outs over the study duration, as well as the fact that TV viewing and physical activity data were collected via questionnaire.

The MNT report added that the cognitive test they performed did not measure all areas of cognitive function.