< Five at 8 - 1/12/10: The Legacy amendment reconsidered | Main | The state of black America >

Study links TV and heart disease

Posted at 10:47 AM on January 12, 2010 by Bob Collins (6 Comments)
Filed under: Health

A study from Australia reports that every hour you spend watching television increases your risk of heart disease by 18%. "What has happened is that a lot of the normal activities of daily living that involved standing up and moving the muscles in the body have been converted to sitting," Dr. David Dunstan says in a news release.

It also contends that each hour of TV is also associated with an 11% increased risk of death from all causes, and a 9% increased risk of cancer death.

Let's do the math. The average person watches five hours of television per day. If Dr. Dunstan's theory is true, our risk of heart disease nearly doubles each day.

It's a good example of framing a study in a way to get the most media coverage. The study is actually about the lack of exercise that people get. It's true, much of their day is spent sitting watching TV, but a lot of people in America's cubicle farms -- work -- are sitting, too. Theoretically is your work increasing the chance of death? Yes.

But the authors said they focused on TV because it's a leisure activity. Still, sitting and reading a book for an hour, could also increase your risk of death.

Comments (6)

Is he saying that each hour contributes to your baseline risk or heart disease, or to the level of risk you have at the beginning of the hour? Basically what I'm asking is: Is this calculated like compound interest? If a person watches 5 hours a day, and lives for, say, 70 years, how long does it take to hit 100% risk of heart disease? For that matter, what is the average person's risk, percentage-wise?

Posted by Brian F | January 12, 2010 11:19 AM

"It's a good example of framing a study in a way to get the most media coverage."

An underreported angle.

another possible angle: to whom is this news?

thought #3: Could he have released this in the early 50s, substituting radio listening for TV watching?

Posted by bsimon | January 12, 2010 11:45 AM

My parents lied to me. They said all the hours I spent reading as a kid were good for me. Turns out, I should probably be dead by now.

Posted by John P. | January 12, 2010 12:09 PM

Not having read the original study, only the CBS News link, I believe the study concludes that the risk increases based on the number of hours of TV watched per day, not with each cumulative hour of TV-watching over a lifetime. In other words, the average number of hours of TV watched per day.

So, if a person watches an average of five hours of TV per day, their overall risk of heart disease is about 2.3 times what it would be if they didn't watch TV. (Baseline risk x 1.18^5)

That means that even if a person averaged 18 hours of TV-watching per day, their risk of heart disease would be (only) about 20 times their baseline risk.

Posted by Alexis | January 12, 2010 12:44 PM

Alexis - That sounds more reasonable, and I'm guessing that's the most likely finding. Unfortunately, the wording is not entirely clear.
Thanks for sharing your different (and probably correct) perspective!

Posted by Brian F | January 12, 2010 1:06 PM

The phrasing of the CBS lede is:

They found that each hour spent watching television on a daily basis is associated with an 18% increased risk of death from cardiovascular disease.

The link to the authors' Web site, which provides a WSJ article for some reason, says:

for more than four hours a day were 46% more likely to die of any cause and 80% more likely to die of cardiovascular disease than people who reported spending less than two hours a day in front of the tube.

Posted by Bob Collins | January 12, 2010 1:34 PM