What happens when I spend the day sitting around?

The inside story: Remember that old saying "the devil finds work for idle hands"? Spending a lazy day on the sofa may not seem evil to you, but your body finds plenty of ways to make trouble with the sugar, or glucose idling in your bloodstream. Taking a walk or getting any other type of physical activity forces muscle cells to soak up glucose, which it uses to produce energy. On a day when you don't give your muscles enough work to do, glucose goes unused. Over time, a sit-around lifestyle encourages two major problems:

* Your body converts some unused sugar to fat. Build up too much and your butt, thighs, and belly will expand. The latter flab depository is the most worrisome; research shows that fat cells around the waistline produce chemicals that cause insulin resistance and low-grade inflammation, which promotes heart disease and other conditions.

* Having lots of glucose lingering in the blood increases levels of dangerous compounds called AGEs that damage nerves and blood cells. That's why high blood sugar causes diabetes complications such as blindness and kidney disease.

Getting up off the sofa and heading out the door for a walk can help you to avoid these fates, of course. Exercise is a reliable fat burner and research shows that physical activity lowers levels of AGEs, too - among many other benefits.

Conclusion: Sitting around all day may help you get caught up on your favorite cable shows, but it is also a set-up for bad blood sugar, weight gain, and all the problems they can cause.