Should You Ice an Injury? What Research Shows
Key insights
- RICE was coined by the sports physician Gabe Mirkin in 1978 and he publicly withdrew his support for the ice and rest components in 2015; the framework proposed to replace it in 2020, PEACE and LOVE, does not list ice as a treatment at all 5.
- A systematic review of eleven randomised trials covering 868 patients with acute ankle sprain concluded that there is insufficient evidence to determine whether rest, ice or compression changes outcomes at all 1.
- In rats, a twenty-minute ice pack applied immediately after a crush injury delayed the clearance of necrotic fibres and the differentiation of satellite cells by roughly a day, and left the healed muscle with excessive collagen deposition 2.
- A separate rat contusion study found that icing delayed neutrophil and macrophage arrival and blunted vascular signalling through the first seven days, and left a higher proportion of immature muscle fibres at twenty-eight days, although final capillary density and fibre cross-sectional area were unchanged 3.
- The effect ice does deliver reliably is analgesia: in 89 people with acute ankle sprain, an intermittent protocol of ten minutes on, ten off and ten on produced significantly less pain on activity during the first week than a continuous twenty-minute application 4.
Ice is the most reflexive intervention in sport. Somebody rolls an ankle, and within ninety seconds there is a bag of it strapped to the joint. The habit is close to universal, it is taught in first aid courses, and it is the reason a great many people own a freezer full of gel packs. It is also, on the evidence, the weakest of the four letters in the acronym that made it famous.
The short answer is that ice is a good analgesic and an unproven healing agent. It will make an acute injury hurt less for as long as the tissue is cold, and possibly a little beyond that. What it will not reliably do is get you back sooner, and there is a coherent body of laboratory work suggesting that if you apply it hard enough and long enough, it interferes with the repair process it is supposed to protect.
Those two claims are not in tension. They simply describe cold doing different things at different doses, on different timescales, to different tissues. Separating them is the whole of the practical question.
Where the ice habit came from
Gabe Mirkin, an American sports physician, coined RICE in The Sportsmedicine Book in 1978. Rest, ice, compression, elevation. It was memorable, it was cheap, and it spread through training rooms, touchlines and A&E departments over the following four decades with very little in the way of controlled evidence behind it. In 2015 Mirkin publicly stated that the ice and rest components appeared to delay healing rather than assist it, which is an unusual reversal from the person who named the protocol.
The formal replacement arrived in 2020, when Dubois and Esculier proposed PEACE and LOVE in the British Journal of Sports Medicine. PEACE covers the immediate days: protect, elevate, avoid anti-inflammatory modalities, compress, educate. LOVE covers what follows: load, optimism, vascularisation, exercise. Ice appears in neither acronym. The authors place it under the anti-inflammatory modalities to be avoided, noting that although it is widely used for analgesia, high-quality evidence for its effect on tissue healing is absent, and that suppressing the inflammatory response may disrupt repair 5.
What cold actually does to injured tissue
Cooling tissue lowers its temperature, slows nerve conduction velocity, raises the pain threshold and constricts local blood vessels. The analgesia is immediate and uncontroversial. The vasoconstriction is where the argument sits.
Inflammation after an acute injury is not simply damage happening to you. It is the recruitment mechanism for repair, and it runs on a schedule. Neutrophils arrive first. Macrophages follow in two phases: an early pro-inflammatory population that clears necrotic tissue and debris, then a reparative population that supports satellite cell activity and the growth of new vessels. Slow the blood flow into the area and you slow the arrival of both. The mechanistic concern about ice is not that it suppresses a nuisance. It is that it delays an appointment.
What the animal work shows
The clearest experiments are in rodents, because you can biopsy the muscle. Takagi and colleagues crushed the extensor digitorum longus in rats and applied a twenty-minute ice pack to half of them. Degeneration of the necrotic fibres and differentiation of the satellite cells were both retarded by approximately one day in the iced group. At the end of the regeneration period the iced muscle showed impaired regeneration alongside excessive collagen deposition 2. That last detail matters more than the delay: collagen where muscle should be is scar, and scar does not contract.
Singh and colleagues ran a contusion model and looked specifically at the vascular side. Compared with a sham treatment, icing attenuated or delayed neutrophil and macrophage infiltration, and reduced expression of von Willebrand factor, vascular endothelial growth factor and nestin through the first seven days. Twenty-eight days later, the icing group had a significantly greater proportion of immature myofibres. But capillary density did not differ, and neither did myofibre cross-sectional area 3. Read honestly, that study says icing perturbs the process without necessarily ruining the outcome.
Both caveats apply. A crush or contusion injury in a rat hind limb, iced directly on shaved skin over a thin muscle, is not a graded ankle sprain in a clothed adult human with a much thicker layer of tissue between the pack and the damage. The direction of the finding is consistent across laboratories; the magnitude almost certainly is not transferable.
What the human trials show
Far less than the ubiquity of the practice would suggest. A systematic review screened 222 studies on acute ankle sprain in adults and found eleven randomised controlled trials, covering 868 patients, that addressed rest, ice or compression. Five concerned ice. Not one compared elevation against no elevation. The conclusion was that the trials provide insufficient evidence to determine whether RICE therapy is effective 1.
Insufficient evidence is not the same as evidence of no effect. It means the trials were small, heterogeneous in protocol and outcome, and mostly underpowered to detect the differences anyone cares about. But after forty years of near-universal clinical use, an absence of adequate trials is itself a finding about how the practice spread.
The best-known human trial on this question does not compare ice against nothing. Bleakley and colleagues randomised 89 people with mild to moderate acute ankle sprain to either a standard twenty-minute ice application or an intermittent protocol of ten minutes on, ten minutes off and ten minutes on. The intermittent group reported significantly less pain on activity during the first week. Function, swelling and range of motion did not differ between the protocols 4. The finding is useful, and the design is telling: the field was comparing two ways of icing before it had settled whether icing helps.
Realistic expectations
Expect pain relief, in the first hours and the first day or two, and expect it to be worth having. Pain drives guarding, guarding drives disuse, and disuse is genuinely bad for a healing joint. An intervention that lets you load a sprained ankle sooner and more comfortably is not a trivial intervention.
Do not expect to return sooner because you iced. No adequate human trial demonstrates it. Do not expect ice to be the part of the protocol that controls swelling; compression and elevation have a more coherent rationale and, in the case of compression, marginally better support. And do not read the rodent collagen findings as proof that an ice pack scars your ankle. Read them as a reason not to ice repeatedly for a week because it feels productive.
Practical guidance
Use ice as an analgesic, deliberately and briefly. If you are going to apply it, the one head-to-head human comparison favours intermittent application over a single long one: ten minutes on, ten off, ten on 4. Always use a barrier between ice and skin, and take particular care over superficial nerves, at the head of the fibula and the groove of the elbow, where prolonged cold has caused nerve injury.
Confine it to the window where pain is the limiting factor, which for most soft-tissue injuries means the first twenty-four to forty-eight hours. Repeated daily icing across the whole first week is the pattern the laboratory data argues against, and it is also the point at which the rest of the protocol should be taking over.
Spend your attention on the components with a better rationale: protecting the tissue from a second insult in the first days, compressing, elevating, and then loading progressively as symptoms allow. Early controlled loading is the part of modern soft-tissue management with the strongest support, and it is the part ice can quietly displace by making rest feel like treatment 5.
Keep this question separate from the one about cold water and training. Immersing a healthy body after a hard session is a different intervention, on undamaged tissue, with its own literature and its own trade-offs, which we have covered in our piece on whether cold plunging actually reduces inflammation. Nothing above argues against a plunge. It argues against treating a torn hamstring with one.
And get an acute injury assessed. Inability to bear weight, rapid or severe swelling, obvious deformity, numbness or a joint that feels unstable are reasons to see a clinician rather than reach for the freezer.
The Contrast Market Perspective
The thread running through all of this is dose. Cold at one temperature for one duration is analgesia; the same cold applied longer, colder or more often becomes physiological interference. That is precisely why we are sceptical of improvised cold. A bag of ice on a limb delivers an unknown tissue temperature for an uncertain time, and a barrel topped up with ice is a different intervention every day of the week. A plunge that holds a stated temperature for a stated duration is not about being harder on yourself; it is about knowing what dose you took, so that the practice you build is the one the research describes rather than an approximation of it. If you are specifying a plunge or a full contrast setup, Schedule a consultation and we will size the chiller and the tub against how you actually intend to use it.
References
Footnotes
- van den Bekerom MP, Struijs PA, Blankevoort L, Welling L, van Dijk CN, Kerkhoffs GM (2012). What is the evidence for rest, ice, compression, and elevation therapy in the treatment of ankle sprains in adults? Journal of Athletic Training. PubMed ↩︎
- Takagi R, Fujita N, Arakawa T, Kawada S, Ishii N, Miki A (2011). Influence of icing on muscle regeneration after crush injury to skeletal muscles in rats. Journal of Applied Physiology. PubMed ↩︎
- Singh DP, Barani Lonbani Z, Woodruff MA, Parker TJ, Steck R, Peake JM (2017). Effects of topical icing on inflammation, angiogenesis, revascularization, and myofiber regeneration in skeletal muscle following contusion injury. Frontiers in Physiology. PubMed ↩︎
- Bleakley CM, McDonough SM, MacAuley DC, Bjordal J (2006). Cryotherapy for acute ankle sprains: a randomised controlled study of two different icing protocols. British Journal of Sports Medicine. PubMed ↩︎
- Dubois B, Esculier JF (2020). Soft-tissue injuries simply need PEACE and LOVE. British Journal of Sports Medicine. PubMed ↩︎