Quite simply, when we stand still for long periods, the forces of gravity increase the pressure within the veins of the legs where the greater effects happen at the ankle and decreases gradually up the leg and body. This pressure depends on the vertical distance of the column of blood from the heart to the foot. That's why gradient compression stockings are designed with the pressure greatest at the ankle and diminishing as it moves up the leg in order to counter the effects of the higher venous pressures.
Compression therapy products are put on in the morning upon arising, which is typically before any significant swelling would occur, and then removed at night. Throughout the day the compression prevents blood from pooling in leg veins, which in turn helps your overall circulation and lessens or eliminates any leg swelling you may have.
When shopping for compression socks or stockings, it is best to measure earlier in the day before swelling builds in the legs. Measurements taken later in the day after swelling occurs may cause you to choose an item that is too large and then not effective.
There are many types of compression socks and stockings available without a prescription and they do offer wide-ranging benefits. Before wearing a compression therapy of 20 mmHg (Firm Compression) and above, it is generally recommended to consult your health care provider to find out if graduated compression stockings are right for you. If the answer is yes, they can tell you what pressure grade you should buy for maximum benefit and relief.