Written by Dr. Aron Low, PT, DPT, MEd, ATC
Ice or heat? As a physical therapist, that is one of the questions I hear more than any other. Frequently, my patients are surprised by my answer, which is “Which one makes you feel better?” There are a ton of reasons as to why this is my answer, but most important to me is that if it makes you feel good, you should utilize it, especially if it doesn’t have any negative side effects.
First, I want to go over a few myths about both Ice and Heat, and give you some information about both that might help you pick the treatment that is best for you.
There is limited evidence that the use of cryotherapy can decrease edema (swelling). Some studies are showing that when used directly following surgery, there is a decrease in pain, improved ROM, and better adherence to physical therapy, but there is not a decrease in circumferential measurements compared to those who are not treated with cryotherapy. In essence, using ice does not make the swelling going down, especially if you stand back up, as gravity will pull fluid right back to where you MAY have reduced it.
Uses: pain modulation, decreasing secondary hypoxic injury, muscle spasm reduction.
Next Myth: Heat will increase swelling. Using heat, another form of thermotherapy , results in the increase in temperature of the skin due to some external source that is hotter than the temperature of the skin. Physiologic changes to human tissue when heated include increased cellular metabolism, increased blood flow and tissue oxygenation secondary to vasodialation, and increase tissue (collagen) extensibility, meaning it is “stretchier”. Heat therapy can also create relaxation, which can reduce muscle spasms and even decrease pain. Using heat does not increase arterial blood flow and restrict venous blood flow, in fact, it is more likely to do the opposite. Since arterial blood flow usually occurs deeper than the structures you are trying to heat, only the venous blood vessels will dilate, causing increased blood flow FROM the site of injury, taking with it all the waste products from healing.
Uses: prior to stretching/exercise, increase tissue temperature, decrease pain/muscle spasm, increase collagen extensibility, increase peripheral blood flow.
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