AFTER a stressful day, one of the best ways to unwind is in front of the telly bingeing a new TV series.
But researchers have now warned watching television for too long could put you at risk of a number of serious conditions, including dementia.
Their study, which involved more than 400,000 people in the UK with an average age of 55.8, found watching TV for five hours a day increases the risk of developing dementia, Parkinson’s disease and suffering a stroke.
The study, published in the Journal of the American Medical Directors Association, set out to look at the link between recreational screen time and brain health in middle-aged and older adults.
The researchers, from Tianjin Medical University in China, analysed data on 407,792 people between the ages of 37 to 73. Of these people, 40,000 had a brain scan.
During the 13-year follow-up period, 5,227 developed dementia, 6,822 had a stroke, and 2,308 were diagnosed with Parkinson’s.
The daily screen time of more than half the participants (61 percent) was between one to four hours a day.
The average time for watching TV was 2.7 hours, and recreational computer screen time 1.1 hours.
Those in the study who watched TV three to five hours a day were at 15 percent increased risk of developing dementia, compared to those who watched for one hour or less.
Those who spent more than five hours a day watching TV were at a 44 percent higher risk of developing dementia, 12 per cent increased risk of suffering a stroke, and 28 per cent increased risk of developing Parkinson’s disease.
No increased risk was found for spending time on computers, because this type of screen use is linked to more “mentally challenging behaviour”.
The researchers also found more than five hours of TV was associated with less grey matter and smaller memory centres – both of which are tied to brain diseases.
It is unclear why watching TV has these effects on the brain.
One theory is that sedentary behaviour, with lower levels of muscle activity and energy expenditure, leads to chronic inflammation and reduced blood flow to the brain.
So it could be more about being a couch potato rather than regularly enjoying your favourite TV shows.
The researchers concluded: “Restricting daily TV viewing time to three hours a day was shown to be the most beneficial to brain-related disorders.
“This has potentially important implications for public health to to reduce recreational screen time, particularly for TV viewing to exert positive effects on brain health.”
The study comes as lecanemab, the first drug shown to slow the progression of early stage Alzheimer’s, is approved for use in the UK.
Trials, which started in September 2021, showed it could slow cognitive decline by around a quarter in patients with early Alzheimer’s over the course of 18 months.
It’s now been licensed by the UK medicines regulator, the MHRA, which means it can be prescribed privately.
But the National Institute of Health and Care Excellence (NICE) has said “the benefits are too small to justify the cost”, so won’t be available on the NHS.
The price of the drug has not been publicly announced in the UK, but in the United States, it costs around £20,000 a year.
Fiona Carragher, chief policy and research officer at Alzheimer’s Society, said: “Today’s MHRA approval of the first safe and effective Alzheimer’s disease treatment, shown to slow progression, is a defining moment for people with early-stage Alzheimer’s disease in the UK and a significant step towards a more hopeful future.
“But it is disappointing that NICE has not recommended approving lecanemab for use on the NHS at this stage.”
Lecanemab is an intravenous, antibody infusion therapy that removes amyloid beta protein from the brain in people with early Alzheimer’s disease.
Amyloid beta protein occurs naturally in the brain, but in people with Alzheimer’s disease, it builds up to toxic levels and forms plaques that disrupt cell function and kill brain cells.
Joan Murtaugh, 77, was one of the first people to take the drug. She joined a trial of the medicine after being diagnosed with mild cognitive impairment and high risk of Alzheimer’s.
Joan, from Ohio, said she is still able to live independently and her memory has improved.
She told The Sun: “I feel perfectly normal and I’m not having the issues that I was having.
“I’m totally functional and my memory is much better than it was.
“I’m very active, I drive regularly, I garden and cook, I read a number of books and I have my life back.”
There are a number of things you can do to reduce your risk of developing dementia. Alzheimer's Society offers the following tips:
Do regular physical exercise
Regular physical activity is considered one of the best ways to reduce your risk of dementia. There are two main types – aerobic activity and strength-building activity. Aerobic activity includes activities like brisk walking, running and swimming. Strength-building include exercises like squats and push-ups. A combination of both types of activity is best.
Drink less alcohol
Drinking too much alcohol exposes your brain to high levels of harmful chemicals. You should avoid drinking more than 14 units of alcohol each week. This is the equivalent of one pint of beer and a small glass of wine each day.
Don’t smoke
Smoking harms the circulation of blood around, particularly blood vessels in the brain. The earlier you stop smoking, the more brain damage you’ll avoid.
Stay mentally well and socially active
People who have periods of depression and are socially isolated are at higher risk of developing dementia. Engaging in social activities can help build up your brain’s ability to relieve stress and improve your mood.
Manage long-term health conditions
Certain health conditions, such as high blood pressure, high cholesterol and diabetes can increase the risk of getting dementia. Going for a health check to see if you have any of these is advised. Eating well and regularly exercising can help prevent and manage these conditions.
Protect your eyesight and hearing
Uncorrected vision loss can increase the risk of dementia. Similarly, hearing loss is tied to increased risk of dementia and could be an early symptom. The use of hearing aids has been shown to reduce the risk of dementia to the level of a person with normal hearing.
Protect your head
Traumatic brain injuries caused by a blow or jolt to the head, particularly when a person is knocked unconscious, can start a process in the brain where the substances that cause Alzheimer’s disease build up around the injured area. If you’re in a situation where there’s higher-than-normal risk of head injury, such as riding a bike or playing cricket, make sure to wear protective headgear.
