Common question about using ice or heat
One of the most common questions asked in outpatient physical therapy clinics is, “How long should I ice an injury?” When should ice be applied, and how long should you keep the ice on your injured body part?
Ice should be applied to an acute injury for 10 minutes at a time. Any longer than this could result in tissue damage to the skin by frostbite or lack of blood flow. You can apply ice several times each day.
What does Ice do?
When you injure a body part, your body goes through the inflammatory process to help heal the tissue. Hallmarks of inflammation include:
- Increased tissue temperature
And guess what? Your body is really good at sending blood and cells to an injured body part to heal it. Almost too good. That’s why we use ice to control swelling and pain.
When ice is applied to your body, it causes vasoconstriction, which limits blood flow to a specific body part. That limited circulation helps to keep swelling down. The ice also helps to decrease pain signals that you may be feeling after your injury.
Heat is used to increase blood flow to the area of the body that it is applied to. The blood vessels expand and widen, to allow more blood, oxygen and nutrients to the area. We need all of these elements for healing, so therefore, heat will encourage the healing process.
Heat also helps to relax muscle, so can be quite beneficial for chronic muscle tightness and tension, as well as joint stiffness.
For acute injuries, heat is good to use after the first 48 hours, when you stop using ice, and the acute bruising and swelling has slowed down.
You can use a heat pack for 20-30 minutes at a time, every 2 hours.
Heat can also be helpful to use to warm up an area before exercise, especially if you are recovering from an injury.