One of the questions I regularly get asked is “Should I use hot or cold therapy for my injury?”
There is so much research on this topic and it can be a rabbit hole when “googling it” so I thought I’d look at some recent scientific papers to see what the latest research actually is.
Before making any decision, you need to understand the physiological effects of each modality on the damaged tissue or painful site.
The effects of ice on tissue damage.
Ice has been well documented to reduce pain, swelling and spasm to an injured site but what happens to the tissues when the ice is applied? (Wany & Ni, 2021). When we are injured our body sends signals to inflammatory cells (macrophages) which are transported to the site of injury. When ice is applied to the tissue it acts a vasoconstrictor, narrowing the blood vessels restricting blood flow to the area. This impedes transportation of these inflammatory chemicals implying a reduction of inflammation. Cold therapy produces local anaesthesia by decreasing the conduction of nerve signals conveying pain.
Cold Therapy
There are a number of ways cold therapy is now applied through the use of ice packs, ice massage and cold-water immersion to name a few.
For nearly 5 decades, the application of ice on an acute injury has been widely discussed as a treatment modality with a number of acronyms including the treatment method: RICE, PRICE, POLICE. The more recently published PEACE & LOVE challenges these methods excluding it from its protocol, allowing the body to heal naturally and addressing the need for the appropriate management throughout all stages of healing by including the subacute and chronic stages (Dubois & Esculier, 2020).
The RICE principal (Rest, Ice, Compression and Elevation) was first published in 1978. It followed the theory that ice had preserved a limb allowing the first successful reattachment surgery 16 years previously in 1962 (Scialoia D & Scialoia, 2020).
This protocol was reviewed in The Sports Journal in 2020 who concluded the protocol was a myth. After revisiting the effects on the tissues, they discussed the need for a rehabilitation plan in the early stages, how the body requires the inflammation stage to also transport white blood cells to fight infection (not to be confused with swelling) and how ice, therefore, could delay the healing process. The limited research surrounding compression and elevation was also discussed. However, they did agree the use of ice does provide pain relief and should be used if this is the desired outcome (Scialoia D & Scialoia, 2020). Protecting the damaged tissues was later added to introduce the PRICE protocol.
After almost 4 decades since the RICE protocol, POLICE (Protect, Optimally Load, Ice, Compression, Elevation) was recognized as the new management protocol after the literature suggested the immediate need for rehabilitation to load the tissues removing the need for complete rest (Bleakley et al., 2007).
The PEACE & LOVE principle (see below), inhibits anti-inflammatory modalities (NSAID medication, Ice) to the injured tissue to allow the body's natural response of inflammation. As this response delays the healing process these modalities are excluded them from the protocol to accelerate recovery. The principle encompasses all stages of healing as well as multi factorial components of rehabilitation including physical, psychological and educational.
The effects of heat on tissue
Heat acts as a vasodilator, dilating the blood vessels which allows for an increase in blood flow. By raising the temperature of the tissues by 1 degree C, tissue metabolism can increase by 10-15 % enhancing the supply of nutrients and oxygen to the tissue and therefore increasing the rate of regeneration (healing). It stimulates the nerve endings which initiates signals that block the processing of pain signals reducing pain and muscle tonicity, helping them to relax. (Zanoli et al., 2024).
Heat Therapy
Heat can be transferred through varying forms such as heat packs/wraps, energy waves such as ultrasound and over the surface of the body ie hydrotherapy. Superficial heat generally penetrates the area by around 1cm whereas heat through energy waves can penetrate up to 3-5cm.
A review of the literature in 2024 by Scialoia D & Scialoia discussed the use of heat therapy for pain and performance. When discussing the modality for pain relief there was evidence to suggest heat was particularly beneficial for reducing neck pain and increasing range of movement. It was found to have short term benefits improving movement and reducing pain in the lower back. Studies also found strong evidence for using heat on carpal tunnel syndrome and knee pain, positively effecting DOMS, osteoarthritis and those with diabetes.
Hot and cold therapy for sports performance
Warming up to increase tissue temperature through dynamic exercise, heat application, foam rolling and massage is recognised to reduce the risk of injury. Applying heat after exercise also has been shown to reduce delayed onset muscle soreness, improve range of movement and flexibility. This is due to the increased blood flow delivering nutrients and oxygen with the removal of waste products.
In a recent review looking at the effects of hot and cold therapy for DOMS, cold therapy within 1 hour of exercise could effectively reduce pain level and had significant effects within 24 hours but no obvious reduction after 24 hours after exercise. Applying heat also had reductions within 1 hour with obvious effects on pain within 24 hours and over after exercise (Wang et al., 2021).
A study from 2022 concluded that within 24 and 48hours post exercise the application of heat was superior to other interventions whereas over 48 hours cold therapy was the optimal intervention for DOMS (Wang et al., 2022).
Which and When
This question has been debated for many years. The answer very much depends on the nature of your injury and what it is you are trying to achieve, whether your injury is recent, a chronic pain (over 3 months) or using the modality for preparing for performance or recovery. Although there is some guidance, it isn’t all completely clear and some of the literature may surprise you.
The stages of healing should always be considered and dictate the correct treatment method. The aim of the treatment in the initial inflammatory stage (up to 72 hours) is to reduce pain and manage swelling. Whilst some papers discuss the need to allow inflammation as an important part of the healing process, pain reduction aids in recovery. In this stage applying heat would only exacerbate inflammation and oedema and is therefore not recommended as a treatment modality.
In the second proliferative stage new tissue and scar tissue forms, heat can now be applied to increase cell activation, providing nutrients and oxygen to the injured site and remove waste. To apply ice at this stage would prevent blood flow to the area and therefore prolong the healing time.
In the third phase the structure requires restoration and function with the blood supply transporting the release of growth hormones to the site. Heat therapy can help improve this supply continuing to accelerate the healing process.
To summarise, for injuries in general, cold therapy in acute conditions should be used for up to 72 hours with heat applied thereafter.
How long
Ice application should be no longer than 20 minutes each hour. Care should be taken to ensure there is no direct contact with the skin and the period of time is not extended. By restricting blood flow and therefore oxygen to the area for long periods there is a risk of tissue or nerve damage. (Scialoia D & Scialoia, 2020).
It is also important to remember there are cautions and contraindications to both hot and cold therapies. Caution should be used with patients with immune diseases, neurological diseases, infections, circulation defects as an example. If you are in any doubt, consult a professional.
What I found interesting with this research and general observation is the number of people
who still believe that “R.I.C.E” is always the correct approach. How many times have you been told to stick some frozen peas on an injury for days on end, rest and elevate it when actually is the right approach to heal naturally and move. What other 50-year-old advice do we follow?
Each injury is different, pain levels and movement abilities vary. There’s no simple answer. To optimise recovery an individual plan is suggested for advice on treatment and exercise load.
Peace and Love Acronym (Dubois, B., & Esculier, J. F. 2020)
P | Protect | L | Load |
E | Elevate | O | Optimism |
A | Avoid anti inflammatory | V | Vascularistion |
C | Compression | E | Exercise |
E | Education |
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Dubois B, Esculier J. Soft-tissue injuries simply need PEACE and LOVE British Journal of Sports Medicine 2020;54:72-73.
Scialoia, D., Swartzendruber, A. J., & Scialoia Saint Joseph, D. (2020). The RICE protocol is a myth: A review and recommendations. The Sport Journal, 24.
Bleakley, C. M., O'Connor, S., Tully, M. A., Rocke, L. G., MacAuley, D. C., & McDonough, S. M. (2007). The PRICE study (Protection Rest Ice Compression Elevation): design of a randomised controlled trial comparing standard versus cryokinetic ice applications in the management of acute ankle sprain [ISRCTN13903946]. BMC musculoskeletal disorders, 8, 1-8.
Wang, Z. R., & Ni, G. X. (2021). Is it time to put traditional cold therapy in rehabilitation of soft-tissue injuries out to pasture?. World journal of clinical cases, 9(17), 4116.
Yutan, W. A. N. G., Hongmei, L. U., Sijun, L. I., Zhang, Y., Fanghong, Y. A. N., Huang, Y., ... & Yuxia, M. A. (2022). Effect of cold and heat therapies on pain relief in patients with delayed onset muscle soreness: A network meta-analysis. Journal of rehabilitation medicine, 54.
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