The ice or heat?: A common dilemma

Should I use ice or heat? This is one of the most of the most frequently asked questions in our clinic. Consider this common scenario: a patient enters the emergency department with severe back pain. The emergency doctor examines the patient and may even take some x-rays. He then determines that the severe pain is resulting from severe muscle spasms in the low back. He treats the patient with an injection of pain medication and releases the patient with a prescription for pain medications and instructions to apply a heating pad to the low back to alleviate the muscle spasms. (Yikes!). The patient then presents to our office a few days later because of persistent pain. We tell the patient to apply ice to the low back. Huh? How confusing!

A commonly-used rule of thumb is to apply ice for the first 48 hours after an injury, then apply heat as the inflammation subsides. So why do emergency room doctors tell people with acute back pain to use heat? The reason is because it is a common misconception that the use of heat has a relaxing effect. (Let’s be honest -- a heating pad just sounds better, doesn’t it?) But in fact when an injury occurs, muscles surrounding the site of injury (e.g., an ankle or shoulder or low back) go into “splinting” mode -- they contract or spasm in an effort to stabilize and/or protect the inflamed area. The key word here is INFLAMMATION. Applying heat to an acute strain or sprain -- an area of INFLAMMATION -- will actually INCREASE the inflammation because heat is pro-inflammatory. So, while it feels good while it is being applied, a heating pad can actually take an injury that would normally resolve nicely in 3 days and turn it into a problem that doesn’t resolve for weeks! It is vital to treat the underlying injury and inflammation since that is what is causing the muscles to go into spasm in the first place. When the inflammation subsides, so does the muscle spasm.

Cold slows chemical reactions and slows the transmission of pain signals to the brain. Ice causes blood vessels to constrict, decreasing blood flow and helping to limit the amount of swelling (edema). Swelling impairs the metabolism of the tissue surrounding the injury, decreasing the delivery of nutrients needed for healing as well as the removal of inflammation from the area, which in turns, reduces pain. In addition, ice helps decrease decrease the pain by numbing sore tissues and slow nerve impulses, which interrupts the spasm reaction between nerves.

However, inappropriate icing may make an injury worse rather than better. For some people, spending over 20 - 30 minutes continuously applying ice can be counterproductive. Have you noticed that when you play in the snow throwing snowballs with your bare hands that initially the hands are blanched and chilled by the snow? Then eventually your hands start to turn bright red and warm despite the continued contact with the snow. This redness and warmth indicates that prolonged exposure to the icy snow is actually increasing blood flow to the hands. Basically, when body tissues are cooled, nerve cells in the chilled area initially force adjacent blood vessels to constrict, leading to a marked reduction in blood flow in that portion of the body. However, if the temperature of the affected area continues to drop the blood vessels begin to open up again to prevent freezing of tissue, even though cold is still being applied. This prolonged exposure to cold may actually increase inflammation and pain as the circulation returns to the tissues. So don’t fall asleep on that ice pack!

How to appropriately apply ice:

• Apply ice to the injured area for 15 minutes each once or twice hourly.
• A 15-30 minute minimum interval between each application will allow sufficient time for tissues to “re-set.”
• Before the tissue warms up fully, apply the ice again. Do this more frequently the first 48 hours and then decrease to 3-5 times per day until the injury resolves.
• Icing frequently in the acute stage can speed up the healing process.
• Some individuals with certain circulatory abnormalities should avoid the use of ice.

Re-freezable gel packs are the most common type of application for ice. They’re convenient, easy to use and mold to any body part. To prevent frost bite remove all frost from the gel pack or other source of cold. Consider placing a moist paper towel between the ice pack and your skin. A barrier too thick will not allow for sufficient cooling.

Ice cups are useful for ice massage around smaller areas of the body including hands, feet, ankles, elbows, shoulders and knees. Fill a Styrofoam or a paper cup with water and place it in the freezer. Once frozen, peel away the styrofoam/paper around the top of the cup, exposing a solid 'bulb' of pure ice.

An ice bag with ice cubes or crushed ice also works, but can be messy if it leaks. Use a damp towel under this type of ice bag to prevent damage to the skin, particularly in older persons and those with diabetes.

Heat
Heat is beneficial for use on chronic and non-inflammatory injuries. Moist heat therapy is characterized by the application of warm, moist compresses to the body as a natural remedy for the relief of pain and a renewed sense of health. Just as with ice, there are various modes of application.

Methods of heat application consist of hot water (hot tub/Jacuzzi), a soaking soothing cloth, ultrasound, or a microwaveable moist heating pad. Moist heat is more beneficial. A dry heating pad should be avoided. Using a hot wet towel or a wet towel between your skin and the heating pad is a good way to produce moist heat. (Warning: do not use wet towels or anything that contains water with an electric heating pad or blankets! Do not use a dry heating pad!).

Moist heat therapy stimulates the thermoreceptors in the body. Thermoreceptors work by blocking the body's pain transmitters from making their way to brain-and the end result is a significant decrease in painful sensations. Moist heat can help decrease joint and muscle stiffness, relax sore muscles, and provide soothing comfort, especially in arthritic joints.

Warming therapies are not recommended to be used on acute inflammation or trauma because a boost in circulation and warmer temperature of the limb is like pouring gasoline on a fire. Applying heat too early can worsen the inflammation and make the pain more severe. Do not use heat on open wounds or if you have areas of numbness (cannot feel if it is too hot -- as in diabetes, for example), increased sensitivity to heat, circulatory problems, infections or malignant tumors.

So, the take home message here is if the affected area feels or appears hot, swollen and tender to the touch, ice. If the affected ares is stiff and it takes firm pressure before pain is felt, heat.