It's not just how much exercise you get, but also how much time you spend off your bottom that keeps your heart healthy

Another day, another study that confirms the dispiriting reality thatsitting is bad for you. Fortunately, says that same study on heart health published in Mayo Clinic Proceedings, it doesn’t take much to offset the harmful effects of sitting.
Because exercise has a more powerful effect in helping the heart than sitting does in harming it, one hour of physical exercise could counteract the effects of sitting for six to seven hours a day, according to researchers led by Dr. Jarett Berry at UT Southwestern Medical Center.
The data Berry and his team reviewed came from the National Health and Nutrition Examination Survey, an ongoing series of health studies maintained by the Centers for Disease Control. The 2,223 participants between the ages of 12 and 49 wore accelerometers for seven days (except while showering or swimming) to measure their activity levels and sedentary behavior, and the result showed that sitting, regardless of the total amount of physical activity the people did, was linked to lower heart fitness.
But it also found that men and women who logged less time sitting had better fitness, as measured on a treadmill test, than those who spent more hours in a chair or on the couch. So instead of focusing on working out, those worried about their health might think instead about sitting less. “Even people who exercise regularly spend the vast majority of their time not exercising,” says Berry. “And it appears that what we do when we’re not exercising is relevant to our health. Understanding this has the ability to shift the paradigm of thinking about exercise more dramatically than anything else in the field of exercise.”
In general, Berry says, any movement, from walking to taking the stairs and even fidgeting if you absolutely have to be in a chair, is likely better than sitting relatively motionless. “Much more work needs to be done, to develop small scale trials to test the impact that lifestyle changes have irrespective of volitional physical activity,” he says. “We spend so much of our time sitting and doing non-exercise-related activities that it’s relevant for us to understand that better.”