You might want to sit down for this. It turns out, while too much sitting can be bad for your health, not all kinds of sitting are equal.

How’s that? We’ve all been told that sitting too long raises the risk of cardiovascular disease and other health problems. But new research suggests that leisure-time sitting has a greater risk of heart disease than sitting at work.

For more than eight years, Columbia University researchers followed nearly 4,000 people who reported how much time they spent sitting at home and how much they sat at work. They also reported how much time they spent exercising each week.

Those who watched TV for four or more hours a day had a 50% greater risk of heart problems and death compared with those who spent less than two hours a day in front of the TV. But those who sat the most at work had the same health risks as those who sat the least.

The difference appears to be what you do when you’re not sitting. Even moderate exercise like walking cut the risk of heart attacks and strokes for those who spent the most time sitting around at home. And those who exercised the recommended 150 minutes or more each week had no greater health risks even if they were glued to the tube for four or more hours a day.

The researchers said it could be that people who watch TV for hours rarely get up, while those at work move around more. Any kind of exercise, even walking around at work, is beneficial.

As for those workers who can’t get up and stretch, like truck drivers, the key may be to offset those down hours with as much physical activity as possible. What you do outside of work may be what really counts.