The severity of inflammation, of capillary permeability, off cells response, is directly related to the temperature of the tissue.
The rapid application of cold causes a decrease in the production of chemical mediators of inflammation.
This reduces from 70 to 80% the amount of algogenic substances and therefore reduces inflammation. This phenomenon is called vasoconstriction and contrasts the vasodilatation of the inflammatory reaction, reducing or limiting the formation of edema.
This vasoconstriction is responsible for a decrease in blood flow output and, consequently, a decrease in fluid output, thus limiting the plasma extravasation responsible for the volume of the edema.

It should be noted that cold does not prevent the release of fluids essential for tissue repair, but only slows it down. This slowdown is largely compensated for by the reduction of the negative effects of the edema and makes it possible to begin rehabilitation much earlier through movement.

Action capable of relieving muscle contractures.

• Vasomotor action

Vasomotor action, regulates the blood flow in the different parts of the body by increasing blood circulation, due to the effect of thermal shock.