[tptacek]

You have to ask yourself, what is the process by which prolonged standing causes or exacerbates atherosclerosis, then try to reason through how much standing you'd need to do to increase your risk significantly. I find stuff like this to be un-encouraging:

A recent study reports a reduction of plasma volume by 500-550ml or about 16% after only 15 minutes of quiet standing. The reduction in plasma volume in turn triggers several changes that can be grouped into hemodynamic and humoral effects, including but not limited to increased hemoconcentration, increased release of catecholamines, changes in pulse pressure, and increased heart rate. For example, one recent study measured a significant increase in heart rate and catecholamines after 10 minutes of standing for men with CVD and also for healthy referents. (em mine)

Increases catecholamines = increased stress.