This is a question I get a lot in clinic. The traditional answer was to use ice for 72 hours for any acute injury or an acute flare up of an existing injury. Use heat for more chronic problems that are nagging and ongoing.
The idea was that icing an injury early on would minimize the inflammation (when inflammation is at its highest) and reduce the pain. Heat promotes healing by increasing blood flow and is generally very soothing – who doesn’t love heat on a sore spot?! Both modalities would typically be applied for 15-20 minutes depending on the size of the body part ie. a finger injury would not generally require as long an application of ice as your low back would.
However, as happens with most things in the health world, the information is changing. Most of the new research is showing that inflammation is an important part of the healing process. If we ice early on to reduce inflammation we reduce the body’s ability to heal properly. Current evidence suggests that we should not take steps to reduce the inflammation of an injury with ice or anti-inflammatory medications. Our body’s innate intelligence is way smarter than we are. Sometimes it is best to just let it do its thing.
In summary, continue to use heat for those nagging and sore ongoing problems. For acute injuries, I recommend using ice as a means of pain reduction and not for inflammation. So if its swelling up but you can deal with the pain, just let the body do its thing. And in the meantime, be as active as you can be to promote healing.
In good health,
Dr Craig