A new study confirms and explains what we've been hearing for a while now: sitting is really, really bad for you. Researchers at the University of Texas Southwestern Medical Center examined data from over 2,000 participants in the National Health and Nutrition Examination Survey (NHANES). They used accelerometer data to determine what the people were doing during their days. And, as it turns out, "sedentary behavior may be an important determinant of cardiorespiratory fitness, independent of exercise." That means sitting is harmful even to those who get plenty of exercise.
As reported in the Mayo Clinic Proceedings, this team's evidence suggests that sedentary activities are harmful because they impact cardiovascular fitness directly. In other words, while activities like walking improve your cardiovascular fitness, sedentary time isn't just neutral — it actually chips away at your fitness gains.
UT Southwestern Medical Center researchers estimate that two hours spent sedentary do as much harm for your fitness as 20 minutes of exercises benefits you. I don't like that math: that means that even if you're fitting in an hour-long daily workout, you undo all those gains with a workday spent at your desk.
If there's any good news in this, it's that the researchers also found that "any movement is good movement." So those dumb tips about taking little work breaks to walk to the water cooler, stretching your legs under your desk, lifting heavy books for a few minutes, etc? Take them. It's not marathon or body builder training, but even small motions can limit how much your sedentary lifestyle harms you.
You might also consider trying a standing desk for at least parts of your workday — if you don't want it taking up space, an ironing board will suffice in a pinch, or you can buy a nifty behind-the-door model. Sitting is also linked to disabilities in old age, so you can thank me later.