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No, TV is not “giving kids cancer”

by Sarah Williams | Analysis

8 January 2013

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Child watching TV

Watching TV or playing computer games will not “give kids cancer”. Image from Wikimedia Commons

“TV & COMPUTER CRAZE IS GIVING KIDS CANCER” – The front page of today’s Daily Mirror might give you terrifying visions of cancerous death rays shooting from the screen.

Rest assured this is not happening. But today’s papers paint a muddled picture about something that is a genuine cause for concern – that living a sedentary lifestyle can increase a person’s cancer risk.

First off, let’s establish what this story wasn’t about. Despite the headlines this story is nothing to do with TV or computer screens themselves. It’s about how “experts” are warning  that spending too long sitting down (as opposed to specifically watching TV or playing games) could increase a child’s risk of cancer later in their life, as it can lead to obesity and inactivity.

But as the symbol of our increasingly sedentary lifestyles, time spent in front of a screen is something most of us can relate to. And so researchers have found it useful to ask how long people spend watching TV or using a computer, to measure how sedentary someone is.

What is sedentary behaviour?

Sedentary behaviour means periods of time spent sitting, or even lying down. It isn’t the same thing as being physically inactive. The government recommends adults get at least 2 ½ hours of physical activity a week from things like walking, gardening, playing sports or exercising in a gym. If someone doesn’t spend any time doing these things, they’re said to be ‘physically inactive’.

But everyone, including the most active among us, probably spends some of their day being sedentary. Whether that’s watching TV, reading a book, sitting on a bus or train, or using a computer – including me writing or you reading this blog.

Sitting, health and cancer – what’s the evidence?

Sitting for long periods means our bodies are burning very little energy. This has been linked to an increased risk of obesity, heart disease and cancer. As an area of research it’s pretty new, so there’s still a lot we don’t fully understand. At the moment the best evidence we have for how long periods spent sitting down could increase the risk of developing cancer is the link with obesity. In other words, long periods sitting can make people overweight or obese, and have higher levels of body fat. We know that fat is an active tissue, pumping out a variety of hormones that are known to increase the risk of cancer.

Is this just about children?

As this Government report from 2010 makes clear, children who spend the most time sitting down are more at risk of obesity.

But the research we mentioned above, linking sedentary behaviour to cancer risk, was carried out in adults. At the moment, it isn’t clear how much the amount of time children spend sitting influences their risk of disease in later life. Nor is it clear whether children who tend to spend more time sitting, do so in adult life. But it’s sensible for everyone – adults and kids – to try and spend less time sitting down: apart from anything else, getting children into habits that will help them to lead a healthy adult life can only be a good thing.

So do I need to be more physically active or less sedentary?

The short answer is yes. Both of these things can help you live a healthier lifestyle and reduce the risk of a range of diseases. Eating a healthy, balanced diet will also help. But remember that sitting down and physical activity (such as walking, exercising, gardening etc) aren’t really opposites. You don’t need to swap time sitting for time pounding the pavements – in fact it’s best to tackle it from both angles.

As we’ve mentioned, adults are recommended to do at least 2 ½ hours of physical activity a week, which covers all kinds of activities. But when it comes to combating sedentary behaviour, the key is to break up long periods of time when you’re sitting down.

Sit less, potter more

So, ignoring today’s headlines about TV and computer games, the take home message here, for you and your children, is to get up and move a bit more often. It could be as simple as going to make a cuppa, nipping out to the shops or mixing some chores in with an evening’s TV viewing. And you can find more suggestions on how to increase your pottering potential on our website.

Sarah Williams, Health Information Officer