Before you despair and hunker down (remote in hand) at the TV, take heart. A growing school of thought says frequent bouts of low-intensity activity - say, walking to the water cooler or up a flight of stairs - can make a difference.
So far, the science supporting this is sketchy. But the concept is prompting studies, influencing health advice, and driving a market for low-cost, compact devices that get the heart pumping, at least a little.
At Pennsylvania State University, for example, researchers tested a compact elliptical (stair-stepping) device that can be used while watching TV or working at a desk. Even though the participants - 32 overweight, inactive adults - put the $100 gizmo on a low-exertion setting, they burned more calories than sitting still.
Using the device an hour a day, which would burn an extra 50 calories, might prevent the annual few-pound weight gain that plagues Americans, the researchers wrote.
Lead scientist Liza Rovniak, who studies physical activity and behavior change, said even such mild activity may improve blood glucose and lipid profiles linked "with premature mortality."
The connections between our derrieres, deterioration, and death are complex, but hard to deny.
Consider that from 1970 to 2000, the percentage of Americans with desk jobs doubled, from 20 percent to 40 percent. By 2010, a Bureau of Labor Statistics survey found, only 5 percent reported any vigorous physical activity, and the most frequently mentioned "moderate" activity was "food and drink preparation and cleanup."
Studies have found varying amounts of sitting may be harmful, but 11 hours seems to be a threshold - an easy one to reach if you drive to a desk job and watch TV or surf the Internet after work.
Two years ago, an Australian study of self-reported data from 222,500 people over age 44 found that those who sat for 11 hours or more a day were 40 percent more likely to die over the next three years, whether or not they were physically active the rest of the time. For those sitting eight to 11 hours a day, the death risk was 15 percent higher.
The Cornell study of premenopausal women - which analyzed data from 92,300 women followed for 12 years - found that sitting at least 11 hours daily increased risk of death only slightly, 12 percent.
However, that link was strong even after the researchers made statistical adjustments to account for age, weight, race, and physical activity.
Exercising "protects you somewhat, but not completely" from being sedentary, said Rebecca Seguin, a Cornell University exercise physiologist and nutritionist who led the study.
As experts confront the possibility that hitting the gym after work isn't a panacea for a sedentary lifestyle, they are rethinking the importance of activity throughout the day.
James Levine, a Mayo Clinic endocrinologist, was among the first proponents of what he calls "non-exercise activity thermogenesis" - any physical activity that increases metabolic rate, including such trivial acts as fidgeting or standing up.
Powell in Pittsburgh is a disciple: "One thing I like to recommend that you can do at home or in the office, is squat down a few inches and then stand back up. It works your hips and thighs and helps with balance, and as you sink down farther, it requires more effort."
Levine's work inspired the invention of the "treadmill desk." Although it hasn't caught on mostly because of cost, the concept of working out while you work is gaining favor.
Rovniak found dozens of compact exercise devices online before picking one for her study. (Buyer beware: She said some "rocked like a freight train" or were "as loud as a vacuum cleaner.")
"I advocate any strategy that can help people safely increase their physical activity," she said. "A simple, low-cost strategy I regularly use is a free computer program that prompts me to stand up at my computer and take regular stretch breaks."
For one company's way to fight the battle of the boomer bulge, go to www.inquirer.com/bulge