Full Segment: The human body isn't designed to sit all day but our jobs often require it. Now new research suggests doing so not only causes weight gain and joint damage but diabetes, heart disease and even cancer. We look into how to help yourself be healthy.

As we work, we sit more than we do anything else. Excessive sitting, defined as nine hours a day, has been called a lethal activity. So four years ago I switched one meeting from a coffee meeting to a walking-meeting, and I've noticed some unanticipated side benefits.

Where do you fall on the sitting spectrum? This study classified low levels of sitting time as under three hours a day, moderate levels of sitting time as three to eight hours, and high levels of sitting as more than eight hours of sitting each day.