Varicose/Spider Veins
Veins bring blood bag to the heart. Veins have internal one-way valves which, when working properly, allow blood to go towards the head but prevent it from dropping back down.
If the the vein valves go bad, blood does not return back up to the heart, causing pooling and engorgement of the vein. Engorged veins start out small (spider veins) and become larger with time (varicose veins).
Once established, spider veins and varicose veins never get better with time-only worse. pooling of blood makes the heart work harder to circulate because circulation of a varicose vein is severely reduced. Prolonged standing or sitting, obesity and pregnancy are common conditions which cause varicose veins.