Every hour spent watching TV, DVDs and videos as an adult reduces life expectancy by almost 22 minutes, a study suggests.
And viewing TV for an average of six hours a day can cut short your life by five years.
The research claims that a sedentary lifestyle is as bad for health as smoking and obesity, because of the dangers posed by inactivity and the greater opportunities it offers for unhealthy eating.
The academics conducting the study set out to calculate the overall risk to life expectancy from watching television. Their research involved more than 11,000 people over the age of 25.
Writing in the British Journal of Sports Medicine, they concluded: ‘TV viewing time may be associated with a loss of life that is comparable to other major chronic disease risk factors such as physical inactivity and obesity.’
This finding is also comparable to risk factors such as smoking, with other research showing that one cigarette cuts 11 minutes off a lifespan – equivalent to half an hour of watching TV.
Researchers from the Harvard School of Public Health, Boston, said it was ‘biologically plausible’ that prolonged TV viewing results in disease and premature death. Other work suggests that sedentary behavior is linked to obesity, high levels of bad blood fats and other heart disease risk factors, and more opportunities for grazing on junk foods.
In another meta-analysis, published earlier this summer in the Journal of the American Medical Association (JAMA), researchers suggest that spending just two hours a day in front of the TV raises your risk of developing type 2 diabetes and heart disease by 20 percent. Add another hour to your viewing time, and you also significantly raise your risk of premature death from any cause.
One researcher, Dr. Aric Sigman, has identified a slew of negative effects he believes can be blamed on watching television:
- Delayed healing
- Heart trouble
- Decreased metabolism
- Damaged eyesight
- Alzheimer's disease
- Decreased attention span
- Hormone disturbances Cancer
- Early puberty
- Sleep difficulties
- Increased appetite
- Limited brain growth
Watching TV also has a major impact on your brain chemistry. In fact, the longer you watch, the easier your brain slips into a receptive, passive mode, meaning that messages are streamed into your brain without any participation from you. (This is an advertiser's dream, and likely one of the reasons why TV advertising—particularly ads directed at children and teens—works so well.)
England’s Chief Medical Officer, Sally Davies, said: ‘Physical activity offers huge benefits and these studies back what we already know – that a sedentary lifestyle carries additional risks. We hope these studies will help more people realize that there are many ways to get exercise.’
Another study shows that exercising for just 15 minutes a day can increase your lifespan by up to three years.
It can reduce the risk of early death by 14 per cent, with each extra 15 minutes reducing all-cause death rates by 4 per cent.
Exercise also protects against cancer, although the benefits peak at 100 minutes a day, says the study in The Lancet medical journal.
It involved more than 400,000 adults taking part in a medical screening programme in Taiwan, whose progress was followed between 1996 and 2008.
The experts found that if individuals engaged in low-volume daily exercise, one in six all-cause deaths could be postponed.
Sources: Daily Mail Online August 16, 2011 and Dr Mercola
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