What is the effect of incompetent valves on post-exercise venous pressures?

Incompetent valves in the venous system lead to a significant increase in post-exercise venous pressures. Normally, during physical activity, the skeletal muscle pump assists in propelling blood upward towards the heart, aided by competent valves that prevent backflow. When valves are incompetent, this mechanism is disrupted.

During exercise, when the muscles contract, blood is forced upward, but the incompetent valves allow some of the blood to flow back down towards the feet, leading to a pooling effect. As a result, there is a higher accumulation of blood in the venous system of the lower extremities, which subsequently causes an increase in venous pressures. This raised pressure can result in symptoms associated with venous insufficiency, like swelling or discomfort.

Thus, the presence of incompetent valves significantly affects venous return dynamics, contributing to elevated venous pressures especially noticeable after exercise, when the muscles have been actively pumping but the backflow from incompetent valves hampers effective circulation.