Prolonged TV watching 'raises diabetes risk'
Couch potatoes beware, say researchers who link prolonged TV watching with an increased risk of diabetes and heart disease.
Every additional two hours spent in front of the box each day raises the diabetes risk by a fifth and heart disease risk by 15%, a study found.
Switching it off and doing something more strenuous instead could stop two people in every thousand developing these conditions, the authors say.
The work appears in the journal JAMA.
"The message is simple. Cutting back on TV watching can significantly reduce risk of type-2 diabetes, heart disease and premature mortality," said lead researcher Professor Frank Hu, of the Harvard School of Public Health.
The researchers say it is not TV viewing per se that is the problem, but that people who spend hours watching programmes are less likely to lead an active lifestyle as a result and, in turn, are more likely to be overweight or obese.
They say other sedentary activities, like sitting in front of a computer playing games or surfing the internet, might have a similar effect, and this should be studied.
The investigators examined the findings of eight large studies that included over 175,000 people and looked at the health risks associated with TV viewing.
The results showed that more than two hours of TV viewing per day increased risk of type-2 diabetes and cardiovascular disease, and more than three hours of daily viewing increased risk of premature death.
The researchers estimate that for every additional two hours of TV watched a day there is an increased risk of an extra 38 people in every 100,000 in the US dying from heart and circulatory disease and 176 people in every 100,000 developing diabetes.
Dr Iain Frame, of Diabetes UK, said the findings should be a wake-up call about the risk of leading a sedentary lifestyle. He said evidence suggests physical activity can reduce the risk of type-2 diabetes by over 60%.
Maureen Talbot, of the British Heart Foundation, said: "I'm sure we've all unintentionally lost evenings slumped on the sofa in front of the TV snacking on crisps and biscuits and drinking sugary drinks or alcohol. But it's important that this doesn't become a regular activity.
"We should try to be selective in how much time we spend watching the TV, and try to be more physically active instead.
"We need 30 minutes of physical activity at least five days a week to keep our hearts healthy, so why not take a walk after work, join a sports team or even just get out for a bit of gardening in the evenings. It's bound to be a lot more rewarding than staring at the box."
According to the researchers, people in European countries spend around three-to-four hours a day on average watching TV, while people in the US do so for five hours a day.