Pedometer Counts Confirm TV Watchers Stay Put

BOSTON, July 27 -- It may seem axiomatic, but a pedometer-based study here has provided empirical confirmation that adults who watch more television are less physically active.

Previous studies relied on individual's self-reports of physical activity, which are subject to recall bias, said Gary G. Bennett, Ph.D., of the Dana-Farber Cancer Institute here.

"Although television viewing has been previously identified as a primary sedentary pursuit, surprisingly few studies have systematically reported its association with physical activity patterns among adults, and none have used an objective measure of total accumulated physical activity," Dr. Bennett and colleagues reported online today in the American Journal of Public Health.

The current study involved 486 primarily black and Hispanic low-income housing residents in Boston. Two-thirds were overweight or obese. All were 18 or older.

Participants wore pedometers during their waking hours to count the number of steps they took every day for one week. The pedometers were "blinded" to prevent participants from knowing how many steps they had taken and possibly altering their normal activity patterns. Participants also reported the number of hours they watched television during the week.

The average participant watched 3.6 hours of television per day, with a range from 0 to 14.5 hours.

Each hour of television viewing was associated with taking 144 fewer steps per day (95% confidence interval=-276 to -12).

Each hour of TV watching was also associated with a 16% reduction in the likelihood an individual would achieve 10,000 steps per day, a figure that roughly correlates to national physical activity guidelines (OR=0.84; 95% CI=0.71 to 0.99), the researchers said.

Although the study did not report the average steps taken per day for the study group at large, subgroup analysis indicated many individuals fell far short of that goal, with males taking an average of 5,857 steps per day and females 5,034.

"The amount of time Americans spend watching television weekly is rapidly approaching the length of the average workweek. Accumulating evidence clearly supports the recommendation to reduce hours of television watching as part of a comprehensive plan to increase physical activity (and to reduce obesity)," the investigators said.

"However, such plans should also include specific recommendations for television replacement strategies that require the exertion of physical activity," they added.