If you’re using a standing desk in an effort to burn more kilojoules, University of Pittsburgh researchers have some bad news for you.

The scientists measured exactly how many calories people expended while sitting or standing for 15 minutes. Standing only used a whopping two extra calories on average, according to the new study.

That translates to an extra 33  to 41 kilojoules for every hour on your feet. The difference was not statistically significant—and it’s probably not enough to affect your weight, say study author Seth Creasy, Ph.D.

Most people think that standing helps you burn kilojoules because it activates the major muscle groups in your legs, Creasy says. But the research suggests that it’s not a big enough stimulus to use up energy.

“People have to move around more in order to really increase energy expenditure,” he says.

Case in point: The researchers also measured how many calories people burned while walking for 15 minutes, and the result was 234 kilojoules, a significant increase over sitting, which burned 83 kilojoules in that same time frame.

This doesn’t mean standing is pointless, though. For one thing, changing your posture from sitting to standing for increments throughout the day can ease back pain, Creasy says.

There are also studies that suggest that by activating the muscles in your legs, standing can improve your blood sugar control, he says.

To take advantage of those benefits and increase your calorie burn throughout the workday, Creasy recommends standing up and moving around every 30 minutes to an hour. That could mean stretching in your office, pacing while you take a phone call, taking a quick lap around your building, or doing sets of jumping jacks, if you work in a very private or non-judgemental office.