m closer to the surface (0.17 mm) than the heat (0,3
  mm). The total number of thermoreceptors about 280,000, including 250,000 cold.
  The predominance of cold receptors suggests that exposure to low
  temperatures can have a greater stimulating effect. Method of placement
  receptors provides accurate monitoring of changes in surface temperature
  epithelium, which is determined by the intensity of the withdrawal of heat to the cooling medium.

known that the shell of the body easily withstand hypothermia and tissue cooling
  10 - 12 C ceased normal operations. For wide application of cryogenic
  physiotherapy, distribution areas should limit the amount of supercooling
  nucleus.

  Cold receptors encode information about the temperature of the skin, it transforms
  in the universal signal for the brain - nerve impulses. Increased intensity
  stimulus associated with an increased frequency of impulse activity.

Quantitative relationship between stimulus intensity and frequency signals
  determined by the law of Stevenson, who argues that between feeling and intensity
  physical stimulus, there is a power law. As a factor
  annoying system of thermoregulation invited to consider the threshold signal,
  ie signal associated with the approach of the temperature recorded by the receptors,
  to the value corresponding to the terminal threshold tterm = -2.5