Too Much TV, Computer Time May Hurt the Heart
Study Shows Sitting in Front of a Screen May Be Linked to Heart Risks
WebMD News Archive
Heart Health Goes Down the Tubes continued...
Those risks remained even after scientists accounted for other things known to influence heart health, like high blood pressure, diabetes, socioeconomic and martial status, smoking and surprisingly, even regular exercise.
“It is all a matter of habit. Many of us have learned to go back home, turn the TV set on and sit down for several hours -- it’s convenient and easy to do. But doing so is bad for the heart and our health in general,” says Emmanuel Stamatakis, PhD, a senior research fellow in the department of epidemiology and public health, University College London, in a news release.
“And according to what we know so far, these health risks may not be mitigated by exercise, a finding that underscores the urgent need for public health recommendations to include guidelines for limiting recreational sitting and other sedentary behaviors, in addition to improving physical activity,” he says.
How Sitting Harms the Heart
Though previous studies have found the similar associations between time spent sitting and the risks for heart attacks and strokes, scientists still aren’t sure why being sedentary appears to be so bad for the body.
The current study, however, offers new clues.
Four factors, in particular, seemed to explain about one-quarter of the association between screen time and cardiovascular risks. Those were body mass index (BMI), total cholesterol, HDL “good” cholesterol levels, and C-reactive protein (CRP), which is a marker of low-grade inflammation.
In fact, CRP alone explained 18% of this association.
CRP levels were about 300% higher in people who reported spending at least four hours a day watching a screen compared with those spent less than two hours front of a TV or computer, suggesting that being sedentary may contribute to a kind of chronic, low-grade inflammation.
The study also notes that levels of a key enzyme that breaks down blood fats have been shown to drop by 80% to 90% during sitting, another mechanism that may contribute to heart risks.
“We know that with obesity for example, we know there’s an increase in CRP, and now we’re seeing that sitting has the same ability to elevate CRP,” Steinbaum says.
“As risk factors go, I think that makes it very compelling,” she says.