Q: I had a fracture in my ankle about five months back. Under continuous stress, like hanging for an hour or so, it swells. As per doctor’s advice, I undergo wax treatment. What is the basis for using wax? Can one not use hot water instead of wax?
A: The swelling in the ankle and foot is due to increased accumulation of lymphatic fluid around the injured area. This occurs due to the downward pull of gravity when the person hangs their legs down.
The principle behind wax treatment is the latent heat given off by the molten wax (above 45 degrees C) during its cooling process.
This heat enlarges the blood vessels (a process called vasodilation) below the applied area and helps to effectively drain the accumulated fluid.
This temperature is quite bearable and soothing.
But the latent heat given off by hot water, at about 100 degrees C, is totally harmful to the human body.
Hot water can be used at bearable temperatures but it cools down more rapidly than molten wax.
In the case of molten wax, moreover, the latent heat given off during its change of state, from liquid to solid, helps in vasodilation as well.
