Inflammation is no fun. Alongside the pain it brings, hallmarks of inflammation are swelling, red coloring or flushing, and stiffness in the affected area. Joint inflammation in particular can make motion difficult, hindering normal physical activities. From acute injuries from wrenching a joint to repetitive strain injuries from appendage overuse, the standard treatment that we hear about for joint injuries resulting in inflammation is alternating heat and ice. Indeed, physical therapists at Blue Hills Sports & Spine Rehabilitation frequently use precision icing and heating as a part of their prescribed therapy regimens. But what exactly do high and low temperatures do to inflammation, and why is this simple remedy so seemingly effective in treating joint injuries?
Firstly, it helps to understand a bit about what does inflammation mean. Inflammation is actually a response from the body’s immune system, and in the days before modern medicine, inflammation was one of the body’s main methods for fighting invading pathogens. When an injury occurs, the bloodstream immediately responds to begin healing the wound and to dispense of any bacteria, viruses, or parasites that may have entered the body as a result.
Blood vessels at the injured area dilate, allowing greater blood flow and causing the red coloration that is often seen at the skin surface surrounding the injury. Immune cells to fight potentially dangerous diseases and new cells to replace those that were damaged are recruited into the area. This causes the swelling, and the increased volume places greater pressure on local nerves and muscles, contributing to the pain felt.
The rules to remember for ice and heat therapy are these: ice helps minimize swelling, while heat helps muscles relax.
Heat should not be applied to an open wound or to an injury that is heavily swollen, and ice should not be used on joints that are stiff and not bending well. The source of heat or cold should not be applied directly to the skin; rather, use a cloth or an item of clothing to buffer the extreme temperature. Likewise, any heat used should not be scalding hot, but should be pleasantly warm. A maximum of 20 minutes at a time for hot or cold point therapy is recommended; body-wide warmth therapy in a sauna or in a bath or shower can be done for longer.
Heat therapy works in part by enhancing circulation to the area to which it is applied. The increased temperature causes the blood vessels to widen, and blood flow is further increased. Among other things in the blood stream, this helps to bring white blood cells and stem cells into the area, dispensing of any infections and increasing the speed at which new tissue can be formed to repair the old. Heat also helps muscle fibers to relax and lengthen, reducing complications that arise from muscle tightening or stiffening.
Likewise, increased flow of oxygen and metabolic nutrients into the site can help to improve cellular health and promote wound healing. Heating pads, towels soaked in warm water, or therapeutic heat wraps are good methods for applying localized heat. Warm baths, saunas, or heated pools are good for larger areas or general pain or muscle stiffness.
In contrast, cold therapy can act to shrink blood vessels and reduce the local invasion of blood cells, swelling, and heat associated with inflammation. In situations where swelling is excessive, this can help bring the size of the area and the local blood flow back down to normal levels. Cold also helps to lower general pain from injuries and inflammation. Options for cold therapy include damp towels, frozen peas, ice wrapped in a cloth, or a therapeutic ice pack, which provide buffers from direct cold to avoid freezing the skin.
In certain injuries where there is both swelling and muscle soreness, both ice and heat may be beneficial. Alternating between cold and hot packs for no more than 20 minutes at a time with ample time to return to normal temperature in between can be useful here. Cold therapy will help bring swelling and pain down, and heat will help promote healing and keep muscles from stiffening. As always, it is a good idea to check with your doctor or physical therapist in Boston, Massachusetts on how to care for your specific injury, depending on your injury type, current health status, and medical history.