I have varicose veins on one of my legs (lower left leg). I have been told, more than once, that I should avoid running (or other high-impact exercises) as that might make them worse. I heard this not only from "lay persons" but also from fitness instructors. I also heard the opposite - that it would improve musculature and circulation on my legs and might help make the veins smaller (or at least stop them from growing).
I couldn't find any seemingly reliable reference to this online, though - the closest I got was a WebMD article saying that running "might be uncomfortable" for people with the condition. I'm ok with uncomfortable, as long as I'm not actually hurting myself. Does anyone have any experience or some good source of information on this?