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Using ice
to treat injuries is one of the oldest methods of pain control. Proven
to be safe and effective at reducing swelling, relieving pain and
decreasing muscle spasms, ice therapy is an easy self-care technique
that anyone can administer. Every mother knows to put ice on a bruised
knee after a soccer game or on a teething toddler’s tender gums. But do
you really know how ice works?
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Cold therapy, also known as cryotherapy, works on the principle of heat exchange. This occurs when
you place a cooler object in direct contact with an object of warmer
temperature, such as ice against skin. The cooler object will absorb the
heat of the warmer object. Why is this important when it comes to cold
therapy?
After an injury, blood vessels that deliver oxygen and nutrients to
cells are damaged. The cells around the injury increase their metabolism
in an effort to consume more oxygen. When all of the oxygen is used up,
the cells die. Also, the damaged blood vessels cannot remove waste.
Blood cells and fluid seep into spaces around the muscle, resulting in
swelling and bruising. When ice is applied, it lowers the temperature of
the damaged tissue through heat exchange and constricts local blood
vessels. This slows metabolism and the consumption of oxygen, therefore
reducing the rate of cell damage and decreasing fluid build-up. Ice can
also numb nerve endings. This stops the transfer of impulses to the
brain that register as pain.
Most therapists and doctors advise not to use heat right after an
injury, as this will have the opposite effect of ice. Heat increases
blood flow and relaxes muscles. It's good for stretching tight muscles,
but will only increase pain and swelling by accelerating metabolism.
At a recent marathon event, our staff witnessed the effect of ice versus
heat. A petite grandmother danced by our booth. "It worked!" she called
out. "I was using heat on my knee, but it didn't get rid of the pain.
Last night I followed your advice and iced*. Now I'm dancing! Today I
can run the 5K with my grandson." And with that, she happily jogged off
to the starting line – a perfect example of the benefit of icing. |
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When it comes to cooling
devices, different effects will result due to the device’s ability to
exchange heat. Crushed ice packs* do a better job at cooling the body
than chemical/gel packs, because they last longer and are able to draw
four times the amount of heat out of tissue. The important difference is
that ice packs undergo phase change, allowing them to last longer at an
even temperature, creating a more effective treatment. Most chemical/gel
packs do not undergo phase change. They quickly loose their ability to
transfer heat, limiting their effectiveness to reduce swelling. Their
short duration of cold is not long enough to numb nerve endings, also
reducing their ability to relieve pain.
Cold therapy should always be used as soon as possible after an injury
occurs and continued for the following 48 hours at 15–20 minutes
intervals. Remember – if you hurt yourself, you need to ice!
*Note:
SnowPack Cold Therapy acts and
feels just like crushed ice. It freezes at virtually the same
temperature and has the same melting curve as ice. Also like ice, it
goes through phase change, allowing for over 2 hours of treatment.
Sources:
Cold Steerage
by Mack D. Rubley, PhD, ATC; BioMechanics
Cold Comfort: If you've got an ache,
try an ice pack by Virginia Gilbert;St.
Louis Post-Dispatch
Ice Therapy
by Laurel J. Freeman, B.A., Footnotes, Road Runners Club of America
Disclaimer: This information is not intended as a substitute for
professional medical treatment or consultation. Always consult with your
physician in the event of a serious injury. |
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