Thermo vs. Cryo
Submitted By abefroman
The debate between the applications of thermotherapy (hot) versus cryotherapy (cold) in the treatment of patients in the acute inflammatory phase following injury continues to wage on in the realm of professional healthcare and rehabilitation. For many athletic trainers, whether to use heat or cold therapy is often a personal choice, although cold therapy seems to be more effective for acute pain (Itoh & Lee, 2007). However, for many patients/clients concerned with the effectiveness of a specific treatment coupled with the rate of recovery, hard evidence derived from reliable and consistent research in support of one modality as the most effective, is in high demand. While both hot and cold treatments may be used to alleviate pain and inflammation, the various physical and chemical aspects of these two treatments have vitally different effects on the human body in regards to treatment of inflammation (Itoh & Lee, 2007). In general, temperature alterations have four main effects on surface body tissues, including pain relief (analgesia), muscle relaxation, blood vessel alterations, and connective tissue effects (Wnorowski, 2011). When treating a patient, it is important to know both the effects of the medium or modality being used on the body, as well as the consequences that it will bring to bear in relation to the physiological effects the body is already experiencing due to the mechanism of injury. The inflammatory response is divided into acute inflammation, which occurs over seconds, minutes, hours, and days, and chronic inflammation, which occurs over longer times. During the acute stage of inflammation, the arterioles in the body region that experienced the injury dilate, allowing increased blood flow to the area. As blood rushes to the site of injury, the area swells as additional fluid accumulates in the interstitial spaces of the region, a condition known as edema. The four cardinal signs of an acute inflammatory response are: pain, heat, redness, and swelling. While inflammation is a normal biological response to injury and is vital to the healing process, too much inflammation hinders the healing process and inhibits the flow of nutrients, proteins, and clotting factors in the blood from reaching the area of injury (King, 2007). Therefore, it is important to reduce swelling in order to maintain range of motion in the area, relieve pain, and induce a faster rate of healing. The big question remains: is the use of cryotherapy of thermotherapy more beneficial when reducing inflammation? Cryotherapy is defined as the use of cold temperature as a form of treatment for an injury. Cold may be applied using an ice bag, cold pack, or fluids (such as ethyl chloride) that cool by evaporation (Itoh & Lee, 2007). Physiologically, applying an ice bag an area of inflammation lowers tissue temperature by the withdrawal of heat energy from the body to achieve a therapeutic effect (Kennet, Hardaker, Hobbs & Selfe, 2007). This phenomenon is explained by the Second Law of Thermodynamics which states that all temperature changes result from transfer of thermal energy from high to low across a temperature gradient (Dykstra, Hill, Miller, Cheatham, Michael & Baker, 2009). In other words, heat travels from hot to cold; in this case, from the heat associated as a byproduct of inflammation of the tissue, to the lower temperature of the ice bag. The effects of treatment using cold reach far beyond the superficial surface of the skin, having numerous biological effects on the intricate inner physiological workings of the human body. With regard to the circulatory system, cold causes constriction of small arteries and veins by direct stimulation of the smooth muscle lining these vessels. The benefits of vasoconstriction include decreased hemorrhage and swelling within injured tissues (Wnorowski, 2011). The tangible, physical effects of application of cold may help numb tissues and relieve muscle spasms, acute low back pain, and acute inflammation (Itoh & Lee, 2007). Thermotherapy can have a completely different effect on body tissue. Thermotherapy is defined as the application of heat to treat a disease or disorder by use of heating pads, hot compresses or hot water bottles. Other types of heat therapy might be diathermy or high frequency sounds waves known as ultrasound. According to Itoh and Lee, the application of heat can help increase blood flow due to the relaxation of the smooth muscle in the blood vessels, also known as vasodilation, which causes more blood flow to the injured region. Therefore, the function of heat would be best used after the acute stages of injury and inflammation since heat can increase swelling to the injured area (Wnorowski, 2007). To prove the highly debated question of whether heat or ice therapy is more efficient in the treatment of acute inflammation, consider the following scenario. Olympic gold medalist, Usain Bolt, is running the 100 meter dash. During the middle of the race he falls victim to a strained hamstring and collapses on the track. The athletic trainer immediately rushes to the fallen athlete’s side and notices that his hamstring is warm to the touch, red and slightly swollen; he/she deduces that it is a hamstring strain with acute inflammation. Now the athletic trainer must make an infomed decision whether to use cryotherapy or thermotherapy to treat the injury. In this situation cryotherapy would be the better choice for the acute inflammation of the hamstring strain. Cold therapy with ice is the best immediate treatment for acute injuries because it reduces swelling and pain. Ice is a vasoconstrictor (causes the blood vessels to narrow) and limits internal bleeding at the injury site (Quinn 2007). Vasoconstriction by the blood vessels reduces blood access to the injury site and as a result limits the amount of inflammation. Heat, on the other hand, increases circulation and raises skin temperature (Quinn 2007); therefore the application of heat to manage acute inflammation is counterintuitive. Doctor Dan Wnorowski supports this concept in his article, “Heat and Cold Therapy”, by stating that, “application of heat in the acute stages of injury while swelling is still prominent can actually increase pain and swelling because of the effects of heat on blood vessels.” In other words, the dilation of blood vessels in the presence of heat application can actually be counterproductive in the management of injury during the acute phase of inflammation. In athletic training, it is crucial to employ evidence-based practice and critical thinking skills in order to react appropriately to various injuries that a patient may experience. Evidence-based practice employs the use of the PICO components. PICO is an acronym that stands for patient, intervention, comparison, and outcome. In the scenario above, the athletic trainer examined the patient’s condition, determined the intervention was needed to reduce the swelling of the tissue, compared the benefits of thermotherapy and cryotherapy to the immediate situation, and determined which medium would have the greatest affect to bring about the desired outcome (reduction in swelling). Research provides evidence in support of cryotherapy as the best treatment in the reduction of swelling during the acute phase of inflammation following injury due to the physiological effect of vasoconstriction cold induces within the arterioles. The debate between the use of cryotherapy and thermotherapy in the treatment of inflammation is a classic example of the importance of evidence-based practice and its usefulness to form an educated conclusion and plan of action in the treatment of injury.