Does running worsen varicose veins on legs?

Sort of: Generally, exercise is good for veins. Many times runners who have slender legs will develop very prominent veins that are normal. Veins enlarge because of their need to return more blood from your legs to your heart when you exercise. When you already have bad veins, exercise can sometimes make your legs feel worse. The real issue, though, in developing varicose veins is heredity, not exercise.

Not really: Running/walking activates the calf muscle pump which propels the blood return from the legs. The exercise activity dilates the vv and makes them more prominent and may result in increased sensitivity and the use of compression hose will lessen the discomfort. Running will not worsen the vv, but standing, sitting long periods will do so.

Difficult to say : I do see a lot of hard core athletes get reflux in their ssv this may be due to muscle hypertrophy blocking the ssv from emptying. But as the other doc stated muscle helps propel blood flow back to heart. I think this needs to be further studied.

Running ; veins: If you are predisposed to vein disease and run, the impact at foot strike generates significant torque transmitted to venous valves in the legs. Since these valves are genetically likely to fail, you may be accelerating the process. It is unknown what if any protective effect compression provides. Walking at incline can generate similar mets of exercise with less risk.