One common habit that can harden your arteries

Watch enough TV, and you're bound to see an ad for a funeral home urging you to make your burial arrangements in advance.

Don't change the channel, because they're talking to you.

Parking yourself in front of the boob tube is one of the worst things you could do to yourself, and not just because of the idiotic programming that kills brain cells.

Being sedentary can kill the rest of your body, too -- slowing your metabolism and wrecking your health. As a result, new research in the British Journal of Sports Medicine finds that watching too much of the tube can cause your arteries to stiffen.

Ready for the worst part? You don't need to be a TV junkie for your own arteries to turn rock hard -- just 20 extra minutes a day, according to the study.

The study was done on 30-somethings, but believe me this is true at any age, which is why being sedentary -- whether it's plopped in front of a TV or parked in an office chair -- can increase your risk of diabetes, heart disease, cancer and an early death.

There's a pretty clear answer here, and that's to turn off the TV or computer, get out of your chair -- whether it's a sofa, easy chair or office chair -- and get yourself moving.

Don't bother with a gym, unless you're fond of flushing money down the drain. As I've said before, 30 minutes on a hamster wheel won't undo the damage caused by hours of sitting. The study proves it (again), because daily exercisers who watched too much TV still had stiffer arteries.

The real answer is to get natural movements throughout the day. Get up, go for a walk -- around the block or even around the room -- just keep your meat out of your seat.

While you're at it, try a hobby that has some movement built in: gardening, hiking, walking, golf, tennis -- whatever it is, make it something pleasant, and make it a habit.