Everything you Need to Know About Icing an Injury

After speaking to hundreds of clients in Mississauga about their training injuries over the past year, I realized that nearly everyone used cold application differently. A popular misconception is that you are reaping all the benefits from icing as long as you apply some form of it to any type of injury. Not only can incorrect application of ice prove to be ineffective, it may even do the opposite of what was intended and become damaging to the body. Yes, there are some inherent physical differences in people that call for more or less cold application. Apart from that research has come up with ideal parameters including temperature, duration, method, and purpose for icing that everyone should be aware of.

These parameters optimize the benefits of icing while reducing the risks. Understanding the current evidence behind cryotherapy (cold application for therapeutic benefit) is highly relevant since nearly everyone has used some form of icing for their training injuries. Such evidence provides icing guidelines to more effectively relieve pain, decrease the chance of re-injury, and improve healing time to get you back to the activities you love. Here we examine everything about cryotherapy including the body’s response to it, the clinical reasoning behind its use, correct parameters to follow, effective techniques, and precautions and risks. It is my hope you realize the powerful benefits of this form of therapy by putting it into practice and helping others understand how to use icing for injuries.

Proper Icing Can: Reduce Swelling

Most of us have been in that moment on the floor after a sprained ankle thinking this is going to suck, and it usually does. One wrong or poorly timed step, and you can damage ligaments, tendons, vessels, bones, cartilage, muscles, and the list goes on. Seconds after this occurs, your body initiates the first process of healing known as hemostasis to prevent excess bleeding from damaged blood vessels. As this happens, blood will pool into the tissue surrounding the injury creating a hematoma (blood accumulation outside of its vessels) to occur. The result is an abnormally enlarged body part from all the fluid accumulation, commonly referred to as swelling. You want to minimize swelling because it puts pressure on the surrounding tissue, decreases a muscle’s ability to contract, and hinders range of motion at a joint.

One of the main goals of cryotherapy is to reduce the hematoma at the site of injury. When an area of your skin is exposed to low external temperatures for long enough your body initiates a hemodynamic response. This involves a reflexive vasoconstriction (decreased diameter) in the nearby blood vessels and an increase in blood viscosity (thickness). Both of these processes reduce the flow of blood in the region which effectively minimizes swelling. To picture how the hemodynamic response reduces flow, imagine going from drinking water with a wide straw to drinking a thick milkshake with a thinner straw. Local reduction in blood flow also keeps the cold temperatures contained within the area being iced. The body does this because it will do anything to maintain its core temperature at an equilibrium of approximately 37 degrees Celsius. We as therapists, personal trainers, and athletes take advantage of this ability of the human body. You can be confident that an area of ice application will remain cold without quickly dissipating and affecting your core temperature.

Continue to page 2 to read about how icing can decrease pain and muscle spasms

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.

A solid garden wall with open metal gates with a blue sky in the background and isolated on a white foreground

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

How to Correctly use Ice

Since the majority of the bleeding occurs within the first few minutes of injury, ice should be applied immediately afterwards. Around the first 15 to 30 minutes of cold application, local vasoconstriction decreases blood flow and subsequently reduces swelling. Applying ice for a longer period of time will initiate the hunting response. This is the body’s complete switch from vasoconstriction to vasodilation in the region as blood vessels increase in diameter and allow more blood flow. This happens after approximately 15 to 30 minutes of icing the extremities depending on the individual, and continues to cycle between vasoconstriction and vasodilation. It is the body’s protective mechanism to prevent cell death in the limbs and extremities from ischemia (low oxygen) related to decreased blood flow. This means that after long exposure to cold temperatures, the body will reintroduce blood flow in order to feed the tissue with more oxygen. This protective vasodilation lasts approximately four to six minutes, and promotes swelling which is typically counterproductive.

This is not the case of more is better or personal preference. With regard to the above information, we recommend that you ice an injury no more than 15 to 30 minutes at a time. Afterwards, remove the ice and allow the tissue to gradually rewarm at room temperature and regain its normal homeostasis (biological balance). Giving the limb a break is important. Icing for too long delays the healing process since it reduces local metabolic rate, including metabolites involved in healing. After two hours, you may use ice again and repeat the same steps.  The first three minutes of icing should feel cold, followed by 15 to 30 minutes of analgesia (pain relief) where the pain threshold is increased. The time frames can be quicker or longer in some individuals depending on body type and/or the size of cold application. The longer you apply the ice for the further the cold will penetrate your body which is helpful for deeper injuries. Therefore, it is a good idea to adjust duration of application according to what works best for you and your situation. You may also notice that your skin is a pinkish-red color right after removal, and this is mistakenly presumed to be vasodilation. It is actually an increase of oxygenized hemoglobin (oxygen-carrying molecules of your red blood cells) at the site of application.

Continue to page 4 to know when to use ice and when to avoid it

When to Use Ice and When to Avoid It

Cryotherapy is useful for controlling the symptoms of inflammation immediately after a training injury. Cryotherapy’s ability to decrease nerve conduction speed makes it a great tool to relieve pain and reduce muscle spasms. There seems to be a lot of confusion on whether to use heat or ice when dealing with an injury. They both work for pain control, but heat should be avoided for instances of acute inflammation as it increases blood flow which promotes swelling. Cold application on the other hand can reduce swelling. The following are some cautions and situations where you should avoid using ice.

caution, police, do not enter, risky, risk

Precautions:

There are precautions and safety considerations for cryotherapy that you should be aware of:

1. Before exercise. An athlete or trainer applying ice before exercise can risk further injury for a couple of reasons. One is soft tissue stiffening, primarily in the collagen fibers. If you can imagine what a frozen elastic band will do once you stretch it, the same can be said about your soft tissue when it is cold. Reduced elasticity of muscles and tendons due to cold exposure can increase the risk of a strain while exercising. The other reason is altered proprioception. This is your body’s ability to know where any part of it is in space without needing visual input and it is governed by feedback from proprioceptors. These are nerve receptors that are found in skeletal muscles (muscle spindles), tendons (Golgi tendon organs), and fibrous joint capsules. Sensory nerves decrease in their conduction speed when exposed to cold temperatures, and proprioceptors are no different. To put this into perspective, icing can slow down the nerves that tell you where your body is in space. Colder limbs are more likely to get into risky or incorrect positions while exercising which can increase your risk of injury.
2. Poor/altered sensation. Use caution when the sensation in an injured limb or extremity is already poor or altered. The loss of intact skin from an open wound can also alter it. Altered sensation can become problematic since the person using the ice may not be able to know or report how well it is working. I have seen good physiotherapists and personal trainers in Mississauga do a quick warm & cold differentiation test around the affected area beforehand to make sure that sensation is intact. If you lack a degree of sensation, you risk overdoing the amount of cold application which can become damaging to soft tissue and superficial nerves. A good way to deal with this is to remove the application every five minutes of treatment. Quickly inspect the skin for any abnormal changes in color and test for sensation.
3. Hypertension. High blood pressure is a precaution since the vasoconstriction caused by icing can further increase blood pressure. As you can imagine, when blood vessels decrease in diameter, blood must push with a higher driving pressure to achieve the same flow rate. An increase in blood pressure can cause these individuals to feel unwell or faint, so be sure to monitor for these changes.
4. Children and elders. Younger and older individuals have lower skin integrity and less insulation compared to adults. Ice transfers through their tissue more effectively as a result, meaning they will not require the same extent of cold application.

epa03910744 A stork perches on a stop sign near Immerath, Germany, 15 October 2013, before continuing his journey to search for his favourite food targets - mice, frogs and other small animals. EPA/FEDERICO GAMBARINI

Contraindications:

Cryotherapy however, is contraindicated (not to be used) under the following circumstances:

1. Vasospastic pathologies. These conditions alter the body's ability to react to cold temperatures. Raynaud’s syndrome, a disorder that affects blood vessels in the extremities (fingers and toes) is an important one to consider. When exposed to low temperatures (even if insignificant), these individuals can experience pallor (whiteness) or cyanosis (bluish discoloration) in the extremities due to a sudden, reflexive reduction in blood flow. This cut in blood flow can become dangerous when sustained for too long.
2. Cold-hypersensitivity and intolerance. Intolerance typically refers to symptoms of pain, numbness, and/or color changes that are more pronounced and come on faster than normal in response to cold exposure. Hypersensitivity is more of an allergic reaction to low temperatures, and involves symptoms of redness and itchiness.
3. Impaired circulation. Avoid icing on top of areas of impaired circulation. The body does not have an effective way to manage a hemodynamic response in this area, and you run the risk of tissue ischemia. Cryoglobulinemia and Hemoglobulinemia are two really long names for rare blood conditions that affect circulation and should be considered before icing. The first is a condition in which the blood contains large amounts of a protein called cryoglobulin. When blood temperature drops below 37 degrees Celsius, precipitation of this protein can block blood vessels. Blockage can become significant enough to cause tissue ischemia and gangrene in severe cases. The second condition is related to an interesting reaction to cold exposure. Upon a drop in blood temperature, individuals with hemoglobulinemia will have their urine change to a purple color. This occurs because hemoglobin is broken down and released into the urine.

Risks:

The risks of cryotherapy include pain, fainting, and frost bite. Fainting is a risk since local vasoconstriction can increase blood pressure, and is more likely to happen in those who already have high blood pressure. Symptoms of pins, needles and tingling can also occur. Cold application should be removed immediately if this progresses to painful tingling or loss of sensation. You can reduce these risks by checking your skin every five minutes, wrapping your gel pack or ice bags with a towel, and applying the pack or bag in a position where it is easy to remove if necessary. If you are using an ice bath for your feet, remove them every five minutes to move your toes around. This will make sure the motor nerves that control their movement are not being affected by the treatment.

Continue to page 5 to read about different methods available and how to use them

Different Options Available for Icing

Reading through this article, you are probably aware by now that there are a number of important things to consider before using cryotherapy. You can add body characteristics and icing methods to the list of factors that influence how well cold application can penetrate through your skin. Icing can penetrate more deeply if your body has low subcutaneous fat content in the way. Cold will also penetrate deeper if your skin integrity is compromised (e.g. an open cut) and if local circulation is poor.

The three general methods for icing, ordered from superficial to deep cold penetration are cold gel packs, ice-filled bags, and ice bath. Each method has its own pros and cons I want you to take advantage of when you need to use cold application. Gel packs are the cheapest, easiest, and most convenient to use. Most people have at least one pack at home, and they can be reused by simply throwing them back in the freezer. Ice bags can reach a better depth of penetration into your soft tissue. Using grinded ice to fill the bag is ideal, but ice cubes can work too. They also offer the advantage of molding around a limb better than a gel pack which improves the surface area of contact. The cold from an ice bath penetrates the body deepest because water is a better conductor of heat than air. These are most useful when cooling the extremities since the water can completely envelope every gap and curve of your fingers and toes. However, unlike gel packs and ice bags, you cannot elevate the limb while using an ice bath in most cases. You must also be aware that an ice bath with moving water will create a cooler effect on your skin than still water. Convection (heat transfer by movement of water/air) does not give your skin a chance to reach a homeostasis with the water immediately surrounding it. Water that is warmed by the surface of your skin constantly gets pushed away by colder water, leading to a greater cooling effect.

What to Take from This Guide

Cryotherapy is an effective treatment option to reduce swelling and pain, and improve function after injury. By understanding its effects on the human body, you are better equipped to reason when to use icing. Keep in mind the methods available, duration, cold penetration, contraindications, precautions, and risks involved. Cryotherapy provides the most value when all of these factors are considered.