TV Watching: Cost in Fitness Adds Up

July 27, 2006 -- Unless you pace the floor (or a treadmill) while watching TV, your tube time could be making your fitness profile a little fluffy.

It's not exactly breaking news that TV usually goes with couch-potato behavior, not workouts. Now, researchers are backing up that commonsense belief with scientific muscle.

For every hour spent watching television, people walk 144 fewer steps, says a study published in September's American Journal of Public Health. And, they're 16% less likely to reach the widely-touted goal of walking at least 10,000 steps per day.

The study comes from Harvard School of Public Health's Gary Bennett, PhD, and colleagues.

This news not enough to make you ditch the remote -- even briefly?

Consider this: "The amount of time Americans spend watching television weekly is rapidly approaching the length of the average workweek," Bennett's team writes.

If so, many people truly have miles to go before they sleep in order to reach daily walking goals.

While stride lengths vary, it takes about 2,000 steps to cover a mile. So the recommended 10,000 steps would have you walking five miles per day.

Counting Steps

Bennett's team studied 486 adults living in Boston in 2005.

Participants -- most of whom lived in low-income public housing -- did two things for the study:

• Report their average weekday and weekend hours of watching TV
• Wear a pedometer on their hips for five days to count their steps

The researchers made the pedometers blind. That way, participants couldn't check their steps and walk more to improve their record.

Bennett's team didn't tell participants to walk. They wanted to see how participants behaved without a specific goal.

They found that on an average day, participants watched 3.6 hours of TV and walked 5,329 steps. Tube time was similar on weekdays and weekends.

American Idle

The more TV people watched, the less likely they were to walk 10,000 steps per day.

"Average daily television viewing was associated with a reduction of approximately 520 steps," the researchers write.

That's nearly 10% of the group's average steps per day.

It's not clear if the findings apply to other groups. But Bennett's team isn't letting anyone off the hook.

The results could be even worse for people with higher incomes, who may have more free time and be less likely to walk for transportation, the researchers note.

The study's limits also include the self-reported TV time; self-reported data isn't always perfect.

But the walking data was objective, thanks to the pedometers.

When experts advise people to watch less TV, they should also provide specific recommendations on replacing television viewing with physical activity, write Bennett and colleagues.

Of course, if you've been inactive lately, consult your doctor first.