This is a question which has come up a couple of times lately, and one which I feel that everyone should know the answer to. In fact, not knowing the answer could actually do you some harm. So when should you use cold and when should you use heat, after an injury.
The basic rule to follow is that in the first 48-72 hours of suffering an injury, ice is the way forward.
Cool it down
The aim of applying ice after an injury is to reduce the blood flow to the area to slow any bleeding, as well as slowing the metabolic rate of the tissues to help control inflammation. So, if you’ve gone over on your ankle; fallen hard onto your knees; been kicked in the calf; pulled a hamstring or anything else which happened suddenly, get some ice on it ASAP. It’s also recommended to continue to apply ice every 2-4 hours. Depending on the depth of the injury and size of the area to be treated, keep the ice on for 10-20 minutes. Always use a dry cloth / towel between the skin and the ice to avoid ice burns.
Heat it up
Once you are sure that all bleeding has stopped (no new bruising has appeared for a day) and the injured area no longer feels warm to the touch, then you are safe to apply heat to the area. Usually this will take 2-3 days. In severe injuries it may be as long as a week. The aim of applying heat is to open the blood vessels and encourage a new surge of fresh blood to the area, to help flush out any dead blood and excess fluids. The warmth will also help to reduce muscle spasm. Again, depending on the area being treated, apply for 10-20 minutes at a time.
Never apply heat to a new injury!
Applying heat in the early stages can do more harm than good as it will only increase the bleeding and swelling in the area. If you’re really unlucky, you could end up with something called ‘Myositis Ossificans’.
I won’t go into the details of this but it basically involves growing a new bit of bone within your muscle. And that’s never a good thing!
Mix it up
So you may have also heard people talking about alternating hot and cold. This can be a great treatment to use. Due to the use of heat, this still shouldn’t be done in the first few days, but once bleeding and swelling have stopped it can be really helpful to flush some new blood through the area as the blood vessels constrict and then dilate. This change from one to another also results in a pump like effect to help drain fluids. I would personally use it about a week after an ankle sprain or other injury with some residual swelling to help flush it out. Start with cold for 5 minutes, then warm for 5. Repeat this again (total of 20 minutes) – ending on warm to finish with a nice fresh blood supply.
The only time I can think of when the ‘no heat for 48 hours’ rule doesn’t apply is in the case of cramp, or muscle spasm. When a muscle spasms uncontrollably, this is known as cramp. Because there is no damage to the muscle or bleeding in the area, it’s ok to heat the muscle gently to help reduce the cramp.
There are also some occasions where an older injury may warrant icing rather than heat. For example, when returning to running after a case of achilles or patella tendinopathy, ice may be more suitable than heat, just to calm the injury down and reduce any potential symptoms.
But in general, if you’re unsure – apply ice. When used carefully ice will do no harm, whereas heat could!