Proper Icing Can: Decrease Pain & Muscle Spasms
The inflammatory period of healing should last between one to three days after injury. It is accompanied by the five cardinal signs of redness, heat, swelling, pain, and loss of function. Pain during this time frame is related to two factors. First, the mechanical distension (outward expansion) caused by swelling puts a lot of pressure on the surrounding soft tissue. Then, irritation of nociceptive (pain) sensory nerve fibers at the site of injury also causes pain. These nerves are irritated by chemicals released from damaged tissue.
Cryotherapy can decrease pain by influencing chemicals known as prostaglandins which are lipid compounds released during inflammation. Prostaglandins are produced at the site of injury and function primarily to progress damaged tissues through the healing process. The issue is they also sensitize pain receptors in the area which decreases your threshold to pain. Icing works to reduce this pain sensitization by decreasing the production and release of prostaglandins. NSAIDs (non-steroid anti-inflammatory drugs) such as ibuprofen, aspirin, and naproxen work the same way to decrease pain.
Cryotherapy can also reduce pain by decreasing the speed of nerve conduction. In fact, it is best at decreasing nociceptive (pain) sensory nerve conduction speed. Since these pain sensory nerves are generally smaller in diameter, they are more affected by exposure to lower temperatures than the larger fibers of gentle-touch sensory nerves. Reducing nerve conduction speed inhibits the nerve’s ability to transmit pain signals to your spinal cord. Of course, all sensory nerves are affected to some degree by icing, but it is always nice to know that the pain fibers are the ones affected most! The bonus effect of decreasing nerve conduction speed is that it can also reduce muscle spasms. Spasms are the result of hyper-active nerve fibers that are firing involuntary, and often too frequently. Cold application can decrease the conduction speed of these hyper-active nerves, thereby reducing muscle spasms.
Lastly, cryotherapy follows the gate control theory of pain modulation. To describe this theory in short, let us talk about a scenario we have all been in. Remember the last time you banged your elbow or stubbed your toe and were fortunate enough to live another day? Your first inclination after feeling the tremendous amount of pain was probably to rub it with your hands in an attempt to make it feel better. Believe it or not, your instinct was absolutely correct. By providing the area of pain with another more pleasant form of sensation, you are sending a distraction signal to the spinal cord where all the afferent (sensory) signals meet before they get sent to the brain. Your brain can only focus on so many signals it receives from the spinal cord at the same time. Adding the pleasant sensation of ice on top of the same part of the body where pain is being felt will take a portion of your brain’s focus away from the pain experience. This increases the pain threshold of your body which means you will experience less overall pain.
Continue to page 3 to learn about how long you should be applying ice for