Trade in time spent sitting for something else.
"Too much TV may lead to shorter life." Headlines like that one flooded the media after the publication of an Australian study linking time spent watching television with higher chances of dying from cardiovascular disease. Television watching in itself probably wasn't to blame, unless a steady visual diet of reality shows, crime dramas, and sitcoms damages the heart by numbing the mind. Sitting is the more likely culprit.
If you are like most Americans, you sit for most of the hours you are awake. A handful of studies on inactivity and health might get you to reconsider that position.
From the journals
Researchers have long focused on the health benefits of physical activity. Studies looking at the flip side are now highlighting the costs of inactivity.
The Australian researchers who made headlines followed the health and habits of nearly 9,000 adults, all initially free of cardiovascular disease, for almost seven years. Those who watched television for four or more hours a day were almost 80% more likely to have died of cardiovascular disease over the course of the study than those who watched fewer than two hours a day (Circulation, Jan. 26, 2010).
Ten healthy Danish men volunteered to cut the number of steps they took each day from about 10,000 to under 1,500. In just two weeks, their muscles had become less sensitive to insulin (an early step toward diabetes), they had gained extra fat in the abdomen, and they had lost a significant amount of leg muscle (Journal of Applied Physiology, May 2010).
In a study of 1,700 Canadian adults, those who said they sat for most of the day were 54% more likely to have died during the 11-year study than those who sat less than half of the time. The researchers saw the same trend of more deaths with more sitting even when they looked only at people who reported that they exercised regularly (Medicine and Science in Sports and Exercise, May 2009).
Thinking on my feet
As editor of the Harvard Heart Letter, I used to sit down on the job. I don't mean I shirked my duties, but I did them with my derriere planted firmly in a chair. Frustrated by all this sitting, I recently retired my chair and bought an inexpensive stand-up desk. Now I am on my feet for most of the time I'm at work. I use my legs more and take several thousand extra steps each day. I feel more alert (especially during afternoons following nights when I didn't sleep well), it seems like I am getting more done each day, and my back isn't so achy.
Stand-up desks come in all shapes, sizes, and prices. I adapted the adjustable Fredrik desk from Ikea ($149), but you can build one out of two sawhorses and a plank of wood, or plunk down several thousand dollars for a custom-made model. (A list of stand-up desk options is posted at health.harvard.edu/162.)
You can use a stand-up desk at home for reading the newspaper, paying bills, writing letters, or other sit-down tasks. It isn't a magic bullet against heart disease, and it certainly isn't a substitute for exercise, but it's a decent heart-healthy habit. — P.J. Skerrett
Stand or move
The message from these studies and a host of others is that activity trumps sitting. That doesn't mean you need to spend several hours a day exercising. But the more standing and walking you do, the better. Adding activity to the day is good for almost everyone. But it has the biggest payoff for people who aren't already active.
In an eye-opening study of military veterans living in California, researchers divided the 4,384 participants into five groups based on the amount of physical activity they got each week. As expected, the number of deaths during the eight-year study decreased from the least active group to the most. The unexpected finding was that the biggest decrease was seen between the least active group and the group just above it (Medicine and Science in Sports and Exercise, August 2009). This suggests that for people who aren't active, the investment of even a small amount of time in extra activity can pay big dividends.
If you sit for most of the day when you aren't sleeping, even if you exercise, anything you can do to be more active will be good for your heart, arteries, muscles, and bones. That includes going out for a walk, working in the garden, or standing while you read, watch television, or work (see sidebar).