• opening of blood vessels of microcirculation leading to increased blood flow to area
• increased vascular permeability to protein
• filtration of fluid into the tissue with resultant swelling
• white blood cells (cells responsible for tissue healing) move from vessels to tissues
• tissue repair

Depending upon the tissue involved, regeneration of organ specific cells may or may not occur. Tissues such as skin cell tend to regenerate well, whereas cardiac muscle does not. Where cells are unable to regenerate, collagen cells are secreted and scar tissue is formed.

Throughout history, cold in the form of snow, ice or cold drinkss and water has been used to treat various illnesses in which inflammation, fever, or burning pain is the main manifestation. More scientifically, ice has been used to produce decreased blood flow to an area, analgesia and reduce inflammation.

Cold reduces enzyme function and therefore decreases metabolism. Cold also produces blood vessel narrowing, therefore reducing the size of haematoma formation, but does not occur quickly enough to prevent local bleeding following an injury or operation. Inflammation is delayed by the cold, but is not eliminated. Likewise, swelling is not totally eliminated but in combination with rest and elevation can be controlled.

Typically ice is applied in the form of gel packs, ice blocks in a plastic bag or even frozen peas. Put it inside of a pillow slip or towel so as to not get a frost burn, and place it gently over the effected area for 20 minutes. This can be done every two hours, any more than this is ineffectual. Ice is most effective in the first 24-72 hours following an injury but can provide pain relief for longer with musculoskeletal problems.