Sitting at your job for long periods of time can have profound health effects

So many people have jobs that require sitting behind a desk for much of the day, that they've come to be known as "desk jockeys.'' Plenty of them keep on sitting after the workday is over, sitting at dinner, watching television and sitting at a computer. As you might guess, all this sitting is contributing to obesity.

Logic seems to say that adding a regular exercise routine to a sedentary day would keep a person lean and healthy. But research is suggesting that it's not that simple -- that sitting for extended periods of time is so unhealthy, you can't make up for it just with regular exercise.

That's not great news, but it helps explain why so many desk jockeys have been frustrated by attempts to control their weight through exercise. The good news is that understanding the cause of a problem is the first step in solving it.

Here's what some of the research seems to show about the effects of extended sitting:

-- The electrical activity of muscles appears to drop severely, so that few calories are burned (sitting burns only about a third of the calories used when walking). If you're sitting for most of your waking hours, that doesn't leave much time to burn enough calories during exercise to stay lean.

-- The body's system of handling blood sugar becomes less effective, increasing the risk of diabetes.

-- The body becomes less effective at breaking down "bad" fats, causing HDL cholesterol levels (the good cholesterol) to go down.

One study that looked at why some people gain weight and others don't -- even when they ate the same number of calories -- found that the "non-gainers" were moving more without realizing it. The "gainers" sat two hours more a day than the "non-gainers."

Apparently, lean people move their bodies more, in general, than overweight people. That supports other studies showing that if two people are sitting, the leaner person is probably moving around more in her seat -- fidgeting, talking with her hands and changing positions often. Although both are doing the same thing -- sitting -- in reality, there are major differences in their energy burn.

So, what can less-boisterous desk jockeys do to get their bodies in motion? Here are a few tips:

-- Be consistent. If you're consistently sitting for many hours, you must consistently move the rest of the time.

-- Try to be more active when you have to sit (shift positions, stretch, move the legs).

-- Take frequent active breaks (take the stairs up a floor to go to the bathroom, step outside for some fresh air or walk around the building).

-- If you have to meet with someone, why not do it while walking around rather than sitting in a conference room?

-- Consider using a taller desk designed for working while standing.

-- If you're talking on the phone but not using the computer, try standing during your conversations.

-- Rather than calling or instant-messaging colleagues in your building, take a walk and visit them.

-- Consider using a stability ball rather than a desk chair. Staying balanced on it will get you to use your muscles differently.

-- Make sure to have an active lifestyle when not at work. Develop active hobbies and after-work activities.

-- Do your own household chores. Do you really have to have someone mow your lawn or clean your house?

Accept limitations, but don't give up. Let's be realistic. Maybe you can't look like a personal trainer whose job it is to be in the best of shape, but you can certainly aim to improve.

(Lavinia Rodriguez is a Tampa, Fla., clinical psychologist who specializes in weight management. Contact her at drrod@fatmatters.com .)