Abstract: A portable apparatus for applying cyclic pressure to veins within a person's leg by applying cyclic pressure to an outer surface of the leg, the apparatus comprising a first air chamber having a flexible wall portion adapted to be situated adjacent an outer surface of the leg, a second air chamber adapted to be positioned beneath the person's heel, this second chamber being compressible to force air out of it when the person's heel bears downward thereon and returnable to its uncompressed state when the downward heel force is removed therefrom, and conduit means for permitting air flow between the first and second air chambers, whereby air flows from the second chamber into the first chamber and pressure is cyclically increased in the first chamber urging the wall portion against the leg when the person's heel presses downward on the second chamber, and air flows from the first to second chamber and pressure on the leg is reduced when the person's heel stops pressing on the second chamber.