Ice vs Heat

Updated: Aug 21, 2021

What to use when you get injured!


June 6th, 2020

Ahhh…the age-old question of “should I ice or heat after an injury”?

Well let me say that this debate gets pretty heated in the sports medicine world so let me start with some history on where this all began…

It all starts with the RICE principle (rest, ice, compression, elevation) for acute injuries, which was devised in 1978 and has been popular due to its ease in remembering. RICE so ingrained now that we reach straight for an ice pack after injury. Interestingly, the main creator of the RICE principle has since become outspoken against the use of ice and rest with an injury, and he now wants the RICE principle changed and gone from our brains. But the mnemonic has stuck and the RICE principle and its variations as shown below still remain commonplace in first aid today!

FIGURE 1, 2, & 3: RICE, PRICE & POLICE PRINCIPLES


‘The creator of the RICE principle is now outspoken against rest and ice and wants it changed!’

So to figure out what is best for us after an injury, we need to delve into how ice and heat actually work...

ICE and how it works

When we injure ourselves, there is an increase in blood flow to the area and an influx of inflammatory cells which contribute to swelling and irritation of the nerve endings. This leads to the sensation of pain. Ice acts to cool the outer layers of the skin, creating a numbing effect to the nerves and constriction in the skin’s blood vessels. This was originally thought to be quite helpful in slowing down blood flow and reducing inflammation of the injury.

For ice to ‘work’ it would need to cool the muscle down to around 5 to 10 degrees from the approximately 35 degrees it sits at during rest. However, this physically isn’t possible in 20 minutes. In fact in no study to date has ice even begun to cool past the skin and fat tissue into the muscle/ligament within 20 minutes, therefore the cooling effects are not even getting close to the site of injury!

‘Ice was originally thought to be helpful in slowing down blood flow and reducing inflammation, but no study to date has even shown the ability of ice to even penetrate past the skin and cool down the muscle’

So, if the ice doesn’t even make it to the muscles and ligaments, why do we still ice???

Well make no mistake, the one thing that ice has been shown to do time and time again is to numb the skin over the injury site and reduce pain. But there is no evidence to suggest it helps the inflammatory process and removal of swelling. There are even thoughts it may hinder the recovery process. There is still much ongoing research into this area. 

Wait, what? There’s potential that ice is making my injury worse?

Absolutely. And this is where the debate can get very heated surrounding the lack of evidence. Ice is thought to:

  • delay the inflammation process required

  • make swelling thicker and harder to remove

  • cause more swelling by damaging local cells

  • put us at risk of over doing an activity and potentially creating more damage to the area by numbing the pain

  • increase local cell death by starving the area of oxygen

These things are all very counter productive to our healing process!

Personally, I’m a strong believer in our body’s natural inflammatory response. Our bodies have super hero fighting abilities. Just like our body fights off an infection by increasing body temperature, our body uses inflammation as the first step to repair and remodel injured tissue. Without inflammation the healing process cannot occur, so I try to minimise the use of ice when possible.

So when is it ok to use ice? And how should I use it?

Well ideally, you don’t ice and skip it altogether. Or you use it sparingly. If you do choose to use it to help an acute or chronic injury, I would recommend using it for no longer than 5 minutes or until the area is lightly numb through a towel or bag. Definitely no longer than 20 minutes. And give your skin plenty of time to cool down between uses, otherwise you risk an ice burn.

If you’re actually not in a great deal of pain, then great! Forget the ice!

Cool cool.. so we now know we can ditch the ice, can I use a heat pack instead?

HEAT and how it works

I’m a big fan of a good old fashioned hot water bottle or heat pack and will happily tell you that heat is not only for chronic injuries. Acute injuries that respond best to heat are ones that aren’t considerably swollen, like a back spasm, as heat over a very swollen joint can make the swelling worse. It is hypothesised that heat reduces local nerve irritation, relaxes muscles that are in spasm, and increases blood flow to the injured site to help stimulate healing. In reality it is most likely sending positive messages to the brain that helps calm the pain response. Heat packs should be applied at a mild comfortable warmth for no more than 20 minutes at a time and with rest in between use to allow the skin temperature to return to normal otherwise you risk a heat burn.

The answer to the great debate: Is ice or heat better for my injury?

Here is the kicker - both ice and heat produce only mild pain relieving effects with neither shown to be better than the other. But if you’re deadset keen on putting something on your injuries to help here are my suggested rules to follow:

  • Avoid the use of ice where possible as it may do more harm

  • If the injury is swollen then avoid heat (this does not mean you necessarily require ice)

  • If the injury is very painful, you can apply ice to numb the pain but you can also choose heat to help (if it’s not swollen)

  • Heat generally feels more comfortable than ice on the spine and is appropriate for most back and neck injuries

  • Do not apply ice or heat directly on the skin (go through a light towel)

  • If using ice, only apply it until the skin goes numb and no longer

  • Do not apply ice or heat for more than 20 minutes

  • Wait for the skin to completely return to room temperature before using a heat or ice pain again

  • If in doubt, then don’t use either!

So if the effects of ice and heat are only mild then why even bother? Is there is anything else I can do instead?

Great question and yes.. wait for it.. our new acronym as written up in the British Journal of Sports Medicine (2019) …

P.E.A.C.E & L.O.V.E.


Before the eye rolls start of this new acronym, let me quickly explain it! As John Lennon once sang let’s give peace a chance!

P.E.A.C.E is important in the first few days after a soft tissue injury

  • P is for Protection: Restrict movements that increase pain for 1 - 3 days to minimise bleeding, prevent worsening of torn fibres, and reduce the risk of aggravating the injury. This may involve restricting range of motion or using crutches to take weight off the injury.

  • E is for Elevation: Raise the limb higher than the heart to promote the removal of swelling out of the area. This has low evidence but is recommended due to it’s low risk to benefit ratio.

  • A is for Avoid (Anti-inflammatories & Ice): Certain medications and we now know ice inhibit inflammation and are not recommended as they can impair tissue healing. So yes we have gone from previous acronyms encouraging the use of ice to now the newest one encouraging us to avoid it!

  • C is for Compression: Use elastic bandage or taping to reduce swelling and limit/prevent further bleeding.

  • E is for Educate: See your therapist asap for education on the benefits of an active approach to recovery.

After the first few days, a soft tissue injury requires L.O.V.E. As the Beatles sang… all you need is love!

  • L is for Load: Add mechanical stress and a gradual return to activities as soon as possible. Optimal loading without exacerbating pain promotes repair and remodelling.

  • O is for Optimism: Catastrophising, depression and fear can represent barriers to recovery. Your physiotherapist should encourage optimism whilst remaining realistic about the injury healing timeframes.

  • V is for Vascularisation: Start pain free cardiovascular activity within a few days of the injury to increase blood flow and healing in the injured area.

  • E is for Exercise: Strong evidence supports the exercise for the treatment of injuries and for reducing the risk of re-injury.

I know that the new acronym may seem like a mouthful, but out with the old and in with the new. It’s time to show your injuries some ‘peace & love’.

If you have any questions or comments, feel free to drop them below.


Got an injury??


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Otherwise until our next blog, train safe!

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Reference: Dubois, B., & Esculier, J. (2019). Soft-tissue injuries simply need PEACE and LOVE. British Journal of Sports Medicine. doi: 10.1136/bjsports-2019-101253