Cooling an area of the body after an injury, also called cryotherapy, helps cut the amount of swelling by reducing blood flow. How long you apply ice is a crucial point in cryotherapy. Ice initially causes a reflex reaction in your blood vessels causing them to contract, for 10-15 minutes, followed by a phase where the blood vessels expand. After 5 more minutes the blood vessels contract again. For this reason, the recommendation is to leave ice on for 20 minutes. Wait at least 10 minutes before applying cold again. Icing is most effective in the first 24 – 48 hours after the injury.
After the initial 3 days, one can switch to a hot/cold contrast. In this case apply cold for 10 minutes followed by 10 minutes of heat; repeat this for a total of 40 minutes. The contraction followed by the expansion of the blood vessels will act like a pump to help flush out any lingering swelling. Blood flow will be promoted by finishing with heat and therefore provide the nutrients necessary for healing.
If you are concerned about an injury or have more questions about ice don't hesitate to ask. We'll help you get back on the right track.
Jenna Nodding - Physiotherapist at Ascent Physical Therapy Canmore