Scientists have discovered that watching too much television increases the risk of dementia.
People who watch more than five hours of television a day are 44 percent more likely to develop the debilitating condition, a study of 400,000 people in the UK found.
It was also associated with higher rates of stroke and Parkinson’s disease, with watching up to three hours of TV a day found to be best for brain health. Researchers said the findings “suggest that heavy TV viewing is associated with an increased risk of several brain-related conditions.”
They analyzed data from 407,000 people aged 37 to 73 from the UK Biobank project, 40,000 of whom had undergone brain scans. None had a diagnosed brain disorder at the start of the study.
During the 13-year follow-up period, 5,227 individuals developed dementia, 6,822 had a stroke, and 2,308 were diagnosed with Parkinson’s disease.
Scientists have discovered that people who watch TV for more than five hours a day are 44 percent more likely to develop dementia (stock image)
Participants watched an average of 2.7 hours of TV per day. Three to five hours was associated with a 15 percent higher risk of dementia, compared with those who watched an hour or less.
People who watched for more than five hours had a 44 percent higher risk. There was also a 12 percent higher risk of stroke and a 28 percent higher risk of Parkinson’s disease.
No increased risk was found for time spent on the computer, probably because such screen use is associated with more ‘mentally challenging behaviour’.
The team from Tianjin Medical University in China also found that watching more than five hours of TV was linked to smaller gray matter and smaller memory centers, two factors linked to brain diseases.
But exactly how television viewing has such effects is unclear.
One theory is that sedentary behavior, with low muscle activity and low energy expenditure, leads to chronic inflammation and reduced blood flow to the brain.
Responding to the findings in the Journal of the American Medical Directors Association, James Rowe, a professor of cognitive neurology at Cambridge, said: ‘A few hours did not increase the risk. So, enjoy your favourite TV and then go do something else.’
