Stand up while you read this

I know it's hard to believe, but one of the worst things you can do to yourself is nothing at all.

The simple act of sitting down is a major risk factor for disease and an early death -- and a new look at data on nearly 800,000 people who took part in 18 studies confirms that sitting can actually double your risk of diabetes and heart disease.

Too much sitting down can also raise the risk of kidney disease, especially for women. And to top it all off, people who are sitting down the most have the highest risk of death from all causes, according to the study in the journal Diabetologia.

Now, I know some people think this doesn't apply to them -- they exercise.

But that's not quite how it works. Even if you jog, run, or spend time in the gym each day, sitting down the rest of the time will more than cancel out all your hard work -- and the new study proves it: Even people who engaged in moderate or vigorous exercise shared the risk of diabetes and heart disease if they spent most of the rest of the time sitting down.

And that's why being active means so much more than getting a burst of exercise in the morning or in the evening. It also means getting yourself moving during the day -- simple stuff like standing up for a stretch or a brief walk.

That's easy enough for couch potatoes. You don't even have to turn off the TV to get a little more movement (although you should). Just get up and move around the room.

For office workers, it's a little tougher...but it's certainly not impossible.

Try walking across the office to visit a co-worker instead of solely relying on phone calls and email. Take the stairs instead of the elevator. And just get up and stroll the corridor for a few minutes here and there (as long as that trip doesn't end up in front of the vending machine).

Make getting more movement a priority as if your life depends on it -- because in many ways, it really does.