What Causes Spider and Varicose Veins?
Blood moves toward the heart by valves in the blood vessel, which controls the one-way flow. Sitting or standing for long periods can cause blood to pool in the leg veins, increasing the pressure within the veins. As a result, the veins can stretch from the increased pressure. This may weaken the walls of the veins and damage the valves, making it harder to control the flow and thus increasing pressure. This pressure ultimately leads to the development of spider and varicose veins.