Ice Packs for Injuries and Therapy - Reusable Cold Packs

Standard cold packs can be made of water or a non-toxic, slow-flowing refrigerant gel, such as hydroxyethyl cellulose. Sometimes, plastic beads filled with gel are used in cold packs. The ice or gel is contained within a waterproof bag or envelope.

Instant cold packs are made up of two bags—one filled with water that is located inside a bag filled with a chemical, most often ammonium nitrate or urea. Squeezing the pack releases the water and dissolves the solid chemical, which then results in an endothermic reaction, instantly lowering the temperature of the package.

To use a cold pack, apply it to the sore area for 10 minutes every hour for the first three days after the injury happened, or the pain occurred. Always place a layer of cloth between your skin and the cold pack. This prevents frostbite. Starting on day four, apply cold packs to the affected area three times per day for 15 to 20 minutes each time. You should also apply the pack after activities or exercise.

Most gel packs have a lifetime of 18 to 24 months. The instant packs can sit on the shelf for about the same length of time before you need to activate them. Once activated, they stay cold for two to four hours.

Instant cold packs are good for relieving pain and soreness from arthritis and injuries. They're also effective for general musculoskeletal pain, swelling and inflammation.

In areas where ice isn't immediately available, instant ice packs are also a convenient means for treating sports injuries or applying first aid.

Some gel cold packs are reusable and can be used between 30 and 50 times before they lose efficacy. The chemical instant cold packs that use ammonium nitrate, calcium ammonium nitrate, or urea are not reusable. Once you activate the pack, it will stay cold for a few hours, but it will not be effective again if you try to freeze and reuse it. The chemical-based cold packs are best for travel and places where no freezer is accessible.