Scientists have found that prolonged and even moderate TV viewing impairs human cognitive functions, and also affects the volume of the gray matter of the brain. At the same time, an active lifestyle did not affect the results.
The team of scientists conducted three studies and found out how prolonged TV viewing and a sedentary lifestyle affect a person's cognitive abilities. The results of the work will be presented at the American Heart Association conference on epidemiology, prevention, lifestyle and cardiometabolic health.
More than 10 thousand respondents were selected for the first study. All participants told how much time they spend watching TV. Scientists interviewed volunteers five times - once every few years.
The results showed that people who watch TV for a moderate amount of time or often suffer from more severe cognitive decline - by 6.9 percent - over 15 years. At the same time, the variety of TV programs did not affect the condition of the participants, as did physical activity: playing sports did not improve cognitive functions and did not reduce the risk of dementia.
The second study included 1601 elderly people. They were also asked every few years how much time they spent watching TV. During the last survey, participants underwent magnetic resonance imaging (MRI). Using an MRI of the brain, the researchers examined several structural markers of the brain, including each participant's deep gray matter volume.
The results showed that TV enthusiasts have lower gray matter levels, which indicates a deteriorating brain condition. The relationship between the love of watching TV and the amount of gray matter was stronger when the volunteers spent more time in front of the TV in middle age. Again, the results were found to be unaffected by an active lifestyle.
A third study also found a link between watching television and the amount of gray matter in the brain. In it, scientists evaluated the data from the study on the Risk of coronary artery development in young adults, a total of more than five thousand people studied. Then they underwent an MRI. It turned out that watching TV at an early and middle age is associated with less gray matter. And the increase in viewing time led to a decrease in gray matter volume by about 0.5 percent - similar to the annual rate of atrophy.
Consequently, three studies have confirmed that frequent TV viewing is associated with the development of cognitive impairment. Scientists believe that this work is especially important now, as people spend more time in front of the TV due to the pandemic.