Using ice to treat injuries is one of the oldest methods of pain management. Proven to be safe and effective at reducing swelling, relieving pain and decreasing muscle spasms, ice therapy is an easy self-care technique that anyone can administer. Every mother knows to put ice on a bruised knee after a soccer game or on a teething toddler’s tender gums. But do you really know how ice works?
Cold therapy, also known as cryotherapy, works on the principle of heat exchange. This happens when you place a cooler object in direct contact with an object of warmer temperature, such as ice against skin. The cooler object will absorb the heat of the warmer object. Why is this important when it comes to cold therapy?
After an accident, blood vessels that deliver oxygen and nutrients to cells are damaged. The cells around the injury increase their metabolism in an attempt to absorb more oxygen. When all the oxygen is consumed, the cells die. Also, the damaged blood vessels cannot remove waste. Blood cells and fluid seep into spaces around the muscle, leading to swelling and bruising.
When ice is applied, it lowers the temperature of the damaged tissue via heat exchange and constricts local blood vessels. This slows metabolism and the use of oxygen, therefore lowering the rate of cell damage and decreasing fluid build-up. Ice can also numb nerve endings. This prevents the transfer of impulses to the brain that register as pain.
Most therapists and physicians advise to not use heat right after an accident, as this will have the opposite effect of ice. Heat increases blood flow and relaxes muscles. It’s excellent for easing tight muscles, but will only increase the pain and swelling of an accident by accelerating metabolism.
In regards to cooling apparatus, different effects will result because of the device’s ability to exchange heat. Crushed ice packs do a much better job at cooling the body than chemical or gel packs, because they last longer and are able to draw four times the amount of heat from tissue. The important distinction is that ice packs experience phase change, allowing them to last longer at an even temperature, creating a more efficient treatment. Most chemical or one-time-use packs and gel packs don’t undergo phase change. They quickly loose their ability to transfer heat, limiting their effectiveness to reduce swelling. Their brief duration of cold isn’t long enough to produce numbness, also reducing their ability to ease pain.
Cold therapy should always be utilised as soon as possible after an accident occurs and lasted for the subsequent 48 hours at 15 to 20 minute intervals. Remember – if you hurt yourself, you want to ice!
This information isn’t intended as a substitute for professional medical treatment or consultation. Always speak with your physician in case of a severe injury.