For years, the headlines have shouted that "sitting is the new smoking," spurring folks in desk jobs to ditch their chairs in favor of standing desks. But as it turns out, new research shows that standing all day may actually be worse for your health than sitting.

The study, published in a recent issue of the American Journal of Epidemiology, followed 7,320 participants — half of them men and half women — for 12 years, comparing data about their job types and medical histories. The participants' jobs were grouped by category — those that involved primarily sitting; primarily standing; a combination of sitting, standing and walking; or a combination of other body positions such as crouching and bending.

At the end of the study, researchers found that 3.4 percent of the participants (4.6 percent of men and 2.1 percent of women) had developed heart disease. The likelihood of developing the disease was doubled for those who stood all day when compared with those who sat or did work that involved a combination of standing and sitting or other positions. Even when researchers took into account factors such as body mass index, daily physical activity, and the other physical requirements of the job, the results stayed the same.

Of course, this data shouldn't come as a huge surprise. If you read beyond the headlines of all of those "sitting is the new smoking" articles, you would have seen many that questioned whether standing was really any better than sitting. Standing in one position all day allows blood to pool in the legs, so it's no wonder that it can be hard on the heart to pump it back up.

But the really interesting takeaway from the study was the look at the combination jobs — those that involved either sitting and standing or a mix of other body positions. Overall, participants in these jobs did not have any higher likelihood of developing heart disease than those who sat all day. But when teased out by gender, men in combination jobs reduced their risk of heart disease by 39 percent compared to those in sitting jobs; women in combo jobs were 80 percent more likely to develop heart disease than those whose jobs involved more seat time.

The research did not draw any conclusions as to why these gender differences might exist. But the study's authors did speculate that the types of combination jobs most frequently worked by men and women might have something to do with it. For men, those jobs tended to be occupations such as courier drivers or retail managers. For women, participants whose jobs involved a combination of standing, sitting and other positions were most likely nurses, teachers and cashiers — jobs that can involve a high level of physical demands and stress.

What's the solution? As MNN's Lloyd Alter put it, you don't need to pack away that standing desk just yet. If this study proves anything, it's that staying in any one position — whether that is standing or sitting — is bad for your health. The key is alternating between those positions and incorporating other stress-relieving movement, like walking or stretching as often as possible throughout the day.