Since chronic venous insufficiency is a constitutional disorder, the principles of healthy living can be of major importance in its prevention and treatment. Among these, the influence of physical activities has attracted the attention of the author, who has attempted to analyze the mechanisms of each sport in order to study its effects on the peripheral vessels. As a result of long terme comparative studies, he has been able to classify the various sports into two categories, the sports which are beneficial and those which are harmful in subjects with vulnerable veins. Into the first category come those activities which assist the physiological mechanisms assuring the return of venous blood, in particular walking, swimming, cycling and gymnastics. Into the second category come sports which involve risks of constriction, trauma, and jolting of the vertebral column (skating, rugby, tennis, etc.), as well as all competitive sports because of the risks of thromboses, often unrecognized, and of excessive efforts which strain the valvular mechanism.