The Basics of Cold Therapy

Cold therapy is recommended during the first one to three days after an injury (depending on its severity) in what's known as the “acute” phase of the injury. During this time, the blood vessels around the injured tissues open up, rushing blood, nutrients and fluids to the area to help tissues healing. The problem is that the increased blood flow often causes the healthy tissues surrounding the injury to swell and become inflamed. If swelling and inflammation aren't stopped or slowed, more extensive tissue damage may occur and the injury may take longer to heal. To add insult to injury, the additional fluids in the swollen tissues may press on nerves around the injury site, increasing pain.

Cold therapy reduces swelling and inflammation in a number of ways:

• it lowers the skin temperature, which helps to constrict (narrow) the blood vessels (vascoconstriction);
• it slows the metabolic rate of the injured tissues;
• it slows the body's release of chemicals that dilate the blood vessels (vasodilation), further helping to reduce blood flow to the area.

Cold therapy also numbs the inured tissues and reduces muscle spasm, both of which help to relieve pain.

You should be aware that cold therapy can't reverse swelling that occurs before an injury is treated. But promptly treating an injury with cold therapy can help to reduce further swelling and inflammation of the surrounding tissues.

Using heat during this acute phase of an injury is not recommended because it increases blood flow, which can aggravate swelling. Heat therapy is typically started at least 72 hours after the injury occurrence and is often applied in conjunction with cold therapy (alternating cold/hot/cold applications, each for approximately 10 minutes, repeated up to three times daily).

Useful Products

Gel Packs: These are available in four sizes – small, large, jumbo and long

• Small – 5 x 6 1/2”
• Large – 5 x 12”
• Jumbo – 10 x 12”
• Long - 4 x 22”

These are most practical for localized strains and sprains because they can be easily contoured (molded) to the injured area of the body (such as around the knee or ankle) and are appropriate when it is also necessary to apply compression and to elevate the injury, both of which further reduces swelling. Gel packs are re-useable and can serve both hot and cold therapy needs. Their use for cold therapy requires some forethought as they must be stored in the freezer for several hours prior to use.

Instant cold packs: These are available in two sizes – small and large

• Small – 4 x 6” (2 oz)
• Large – 6 x 10” (5 oz)

Instant cold packs are also ideal, and have the advantage of being less messy than homemade ice packs. They can be stored almost anywhere and can be activated when required. These single use cold packs are often found in first aid kits.

Plastic bag filled with ice or snow (bag of frozen peas)

This is an inexpensive and effective cold therapy treatment, but has the disadvantage of not always having the appropriate cold material available.

Treatment Recomendations

Cold packs should never be used for more than 30 minutes at a time (15 minutes is ideal). Deep tissue injuries take longer to cool than surface tissues. So, for example, apply cold for a longer period of time to a hamstring strain than an ankle sprain. Because muscles have a high water content and are good heat conductors, a heavier person with more body fat will require a longer cold treatment than a thin person with the same injury. If cold is kept on longer, the body thinks that it is going to freeze, so there is an opposite effect. Instead of the vessels constricting they actually dilate. Blood is shunted to that area causing skin discoloration and sometimes even frostbite.

The pack should not be placed directly on the skin. To reduce the risk of frostbite, place a damp towel or cloth between the pack and the skin. Our ice pack covers (shoulder, back, black Velcro and blue double) are ideal. Since too much cold can lead to frostbite and possibly nerve damage, discontinue the treatment when the skin turns numb and do not reapply cold until the skin has returned to a normal temperature.

Cold treatment should be repeated at regular intervals during the waking hours for the first 24 to 72 hours after sustaining an injury, or until the swelling goes down.

You should be aware that cold therapy is not for everyone. It should not be used in the very young and the very old. If you have impaired blood circulation, cold hypersensitivity, hypertension, and/or diminished or absent sensation, you should avoid cold therapy.

Generally speaking, use cold therapy to reduce swelling immediately after sustaining an injury. Use heat therapy only after the swelling has subsided (see Heat Therapy). Alternating hot and cold therapy can be a useful treatment strategy but ensure that the tissue has returned to normal ambient temperature before applying the alternative therapy.

To further reduce swelling and encourage healing during the first 24-72 hours, remember --- R – I – C – E

Rest
Ice
Compression
Elevation