About a year ago I decided it was hard to be in the mainstream of 'normal life' if I couldn't stand for a continuous hour. I wanted to have a catch with my grandson, or mill around at a party. So I very gradually worked my way up to being able to do it daily. Some days are more walking than standing, some the other way around, and sometimes I skip a day. But most days I can do my vertical hour. I'm probably on the mild end of the continuum, so I likely have some aerobic conditioning potential without worsening my health.