Screen time is physiologically distinct from other sedentary activities like reading or being read to. And that's a problem. More >
Watching TV May Shorten Your Life
In a recent Australian study, the more time people spent sitting in front of the TV, the more their risk of dying over the next six years went up.
The most likely reason for this isn't the TV, it's the sitting. Societal changes have meant that many people spend more time sitting than they used to. They spend a large portion of the day shifting from the chair in front of the TV to the chair in the car to the chair in front of the computer. And many people have jobs that are mostly spent sitting. The human body is designed for more movement than that.
This isn't even about exercise; it's about incidental, non−sweaty activity that involves moving, bending and stretching. This helps keep the blood circulating and the muscles from losing tone. People do less of this now than they did in the past.
The researchers wanted to find out what happens when people sit too much. They looked at TV watching because it's the most common sedentary activity carried out in the home.
Over the course of the study, people who watched four or more hours of TV daily had a 46% higher risk of death and an 80% higher risk of death from cardiovascular disease than people who watched less than two hours of TV daily. Each daily hour spent in front of the TV increased a person's risk of death by 11% and of death from CV disease by 18%.
The study was performed on 8,800 adults aged 25 and older. They were enrolled from 1999−2000 and followed through 2006. People with a history of cardiovascular disease were excluded. Participants reported their TV watching habits of the previous week and were placed into three groups: those who watched under two hours daily, those who watched between two and four hours and those who watched over four hours. During the course of the study, there were 286 deaths, 87 from cardiovascular disease.
The study message is simple: too much sitting is bad for you. People who do a lot of sitting should make every effort to move around more. At work, short breaks spent walking around every hour are helpful; at home, almost anything you can think of is better for you than just sitting around.
The results of the study were published online ahead of print on January 11, 2010 and will appear in a future issue of the journal Circulation.
February 1, 2010
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