Couch Potatoes Beware:
Too Much Time Spent Watching TV
Is Harmful to Heart Health
Spending too much leisure time
in front of a TV or computer screen
appears to dramatically increase the
risk for heart disease and premature
death from any cause, perhaps
regardless of how much exercise
one gets, according to a new study
published in the January 18, 2011,
issue of the Journal of the American
College of Cardiology.
Data show that compared to people who spend less than two
hours each day on screen-based entertainment like watching
TV, using the computer or playing video games, those who
devote more than four hours to these activities are more than
twice as likely to have a major cardiac event that involves
hospitalization, death or both.
The study examines the association between screen time and
non-fatal, as well as fatal cardiovascular events, also suggests
metabolic factors and inflammation may partly explain the link
between prolonged sitting and the risks to heart health.
"People who spend excessive amounts of time in front of a
screen, primarily watching TV, are more likely to die of any
cause and suffer heart-related problems," said researchers
from the Department of Epidemiology and Public Health,
University College London, United Kingdom. "Our analysis
suggests that two or more hours of screen time each day
may place someone atgreater risk for a cardiac event."
In fact, compared with those spending less than two hours
a day on screen-based entertainment, there was a 48%
increased risk of all-cause mortality in those spending four
or more hours a day and an approximately 125% increase in
risk of cardiovascular events in those spending two or more
hours a day. These associations were independent of traditional
risk factors such as smoking, hypertension, Body Mass Index,
social class, as well as exercise.
The findings have prompted authors to advocate for public
health guidelines that expressly address recreational sitting
(defined as during non-work hours), especially as a majority
of working age adults spend long periods being inactive while
commuting or being slouched over a desk or computer.
"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," said researchers. "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."
Biological mediators also appear to play a role. Data indicate
that one fourth of the association between screen time and
cardiovascular events was explained collectively by C-reactive
protein (CRP), body mass index, and high-density lipoprotein
cholesterol suggesting that inflammation and deregulation of
lipids may be one pathway through which prolonged sitting
increases the risk for cardiovascular events. CRP, a well-
established marker of low-grade inflammation, was
approximately two times higher in people spending more
than four hours of screen time per day compared to those
spending less than two hours a day.
The next step will be to try to uncover what prolonged sitting
does to the human body in the short- and long-term, whether
and how exercise can mitigate these consequences, and how
to alter lifestyles to reduce sitting and increase movement and
exercise.
The present study included 4,512 adults who were respondents
of the 2003 Scottish Health Survey, a representative, household-
based survey. A total of 325 all-cause deaths and 215 cardiac
events occurred during an average of 4.3 years of follow up.
Measurement of "screen time" included self-reported TV/DVD
watching, video gaming, as well as leisure-time computer use.
Authors also included multiple measures to rule out the
possibility that ill people spend more time in front of the screen
as opposed to other way around. Authors excluded those who
reported a previous cardiovascular event (before baseline)
and those who died during the first two years of follow up just
in case their underlying disease might have forced them to stay
indoors and watch TV more often. The research team also
adjusted analyses for indicators of poor health (e.g., diabetes,
hypertension).
Story Source:
American College of Cardiology
Journal Reference:
Screen-Based Entertainment Time, All-Cause Mortality, and
Cardiovascular Events: Population-Based Study With Ongoing
Mortality and Hospital Events Follow-Up. Journal of the
American College of Cardiology, Too Much Time Spent
Watching TV Is Harmful to Heart Health 2011;
Disclaimer: This article is not intended to provide medical advice,
diagnosis or treatment.
