In previous articles, we have discussed some of the most common sports injuries: The ankle sprain, including both mild sprains and severe sprains. While we touched on treatment, including an article about icing a sprained ankle, we would like to take this opportunity to answer one of the most common questions patients ask when looking for possible adjuncts to their ongoing treatment: “Should I use heat or ice for my sprained ankle?”.
How does ice work for a sprained ankle?
When searching for information regarding the therapeutic effects of applying ice to a sprained ankle, it’s worth knowing that this is often termed “cryotherapy” in more formal clinical settings.
In this article, we will use “ice”, “cold therapy”, and “cryotherapy” interchangeably. This can refer to any method of cold therapy, such as using an ice pack, ice water bath, cryo-cuff, etc.
Furthermore, the evidence behind behind potential benefits of ice as a treatment method for an acute injury is still controversial, including the potential ability to reduce inflammation (Miranda et al, 2021), and as such, any combining this information with a visit to your local physiotherapist will lead to the most optimal patient-centred decision.
Nevertheless, we will discuss the mechanisms of cryotherapy and break down the proposed benefits for treating an ankle sprain.
Cold therapy can work on an ankle joint by altering a number of physiological functions. First, it can reduce local blood circulation by way of vasoconstriction, which simply means narrowing of the blood vessels in that specific area.
While this seems simple, there are a number of biochemical processes happening that trigger this response, both directly on the blood vessels, and indirectly by increasing sympathetic nervous system response.
In addition to vasoconstriction, blood flow can also be reduced due to increased viscosity of blood (almost like thickening the blood) and decreasing metabolic factors that would otherwise make the vessels larger in diameter. Keep in mind that these circulatory effects are in regard to a typical application of ice around 10-20mins in duration.
Additionally, by reducing the sensation of pain and initiating subtle hormonal changes, it is believed that an athlete could improve post-activation potentiation (Partridge et al 2019). For the sake of simplicity, you can think of post-activation potentiation as being the same as power produced during complex movements, such as jumping, sprinting, and explosive change of direction movements.
However, one should interpret this performance data with caution, as these studies usually focus on whole body cryotherapy, such as an ice bath, rather than application of ice specific to the ankle.
Furthermore, there is some opposing evidence that shows this potential performance effect may not be meaningful, for example, one study that showed whole body cryotherapy had no effect on vertical jump performance, at least after one session of whole body cryotherapy (Vieira et al 2015).
We briefly mentioned the effect of ice on sensation of pain. Using cryotherapy for a sprained ankle can affect the nerves that carry specific signals to the brain, whereby these signals are then interpreted as a threat by the brain. The brain reacts by then providing a warning and protective response: the sensation of pain.
Given that an individual doesn’t feel pain until the brain interprets various sensory information as a threat, one can reduce a pain response by slowing the transmission of threatening signals to the brain, ultimately decreasing the sensation of pain.
Both ice and heat can help relieve pain. Specifically, ice can decrease nerve conduction velocity, specifically of nerves that are relatively smaller in diameter. These nerves tend to carry sharp intense pain that is typically shorter-lived, as well as information related to touch, with some specific fibers also appearing to be hypersensitive during the inflammatory phase of healing (Neumann et al, 1996).
By applying ice to slow and potentially block the information being sent along these nerve pathways, one could experience a reduction in pain associated with a sprained ankle especially during the inflammatory phase of healing (Algafly and George, 2007).
Therefore, ice may be more beneficial in the early and sub-acute phases of recovery from an ankle sprain, as it may help with managing pain and swelling, and likely won’t exacerbate the inflammatory process of healing.
How does heat work for a sprained ankle?
As you may have guessed, the application of heat therapy has the opposite physiological actions to cryotherapy on an injured ankle. As such, the effects of heat may or may not be beneficial to ankle sprains depending on the purpose of application. The following information will describe how heat works on body tissues, and we will put this in the context of when it may or may not help with ankle sprains.
When it comes to altering circulation, heat works on similar pathways as cryotherapy, but has the opposite effect. In this case, heat will cause vasodilation of blood vessels, meaning the blood vessels expand in diameter.
Additionally, heat can act to reduce the viscosity of blood, which can be thought of as how thick the blood feels (e.g. ketchup has higher viscosity than water). Therefore, heat therapy can promote blood flow to the area of application (Melanga et al. 2015).
While increased blood flow may seem like a good thing, which it is sometimes, increasing temperature of heat both internally from increased blood flow and externally from a heat pack can induce an inflammatory response.
Inflammation is likely present in the acute stages of an ankle sprain, and therefore, if we are trying to prevent prolonging the inflammatory phase of healing so we can continue to recover, the application of heat may have a detrimental effect in that case.
While ice works to slow nerve conduction velocity of certain nerve fibers, heat does the opposite and increases nerve conduction velocity. So how come heat doesn’t increase pain then? The physiological action of heat on the nervous system is a little bit different. To simplify a complex biochemical pathway, one can simply think of heat as having the ability to block threatening signals, rather than slowing them.
This is often termed the Pain Gate Mechanism, and while reconstructed over the years to be more accurate in its description, the original theory is a great way for non-clinicians to gain a basic understanding of sensation and pain (Mendell 2014).
Basically, one can consider that all sensory information traveling from the ankle to the brain as having to pass through a “gate” prior to being interpreted by the brain. Heat will bombard this pathway with the sensation of increased temperature, and this will cause an effect similar to closing the gate for other threatening sensations that are usually interpreted as pain.
In other words, the brain will receive more information about the heat and less information about the threatening signals, and therefore will lower its pain response.
Heat is also widely considered effective for increasing tissue extensibility. For example, one may notice they have an easier time stretching a muscle after they are warmed up, or that they can move through larger ranges of motion actively after being warmed up (Nakano et al, 2012).
By applying heat to muscles/tendons, it is thought that muscle spindle activity can be reduced. These muscle spindles can detect stretch and be involved in a stretch-reflex response, whereby the spindles tell the muscle to contract in order to prevent being stretched too far. By reducing activity of the spindles, the muscle will be less sensitive to stretch (Newton and Lehmkuhl, 1965).
Additionally, heat can also act on the collagen fibers themselves. Collagen fibers are the main structural components of soft tissue in the body, especially ligaments and tendons. Collagen fibers can be stretched, but this takes energy and they can only be stretched to a certain point.
The application of heat decreases the energy required to stretch the collagen fibers. Therefore, heat can also act to increase the extensibility of soft tissue, such as ligaments and tendon (Chen and Humphrey, 1997).
With ankle sprains, the ligaments themselves are already stretched too far causing some degree of tearing. As such, stretching the ligaments of the ankle is not advised, especially in the early stages of healing, and especially to the injured ligaments which may feel stiff due to swelling and inflammation.
Moreover, the ligaments that are injured in an ankle sprain often heal in way where they are a bit more lax, and as such, the focus should be on ankle strength and stability to help support the ligaments, as opposed to further increasing the laxity of these ligaments.
Therefore, heat may be more beneficial in the later stages of recovery from an ankle sprain when there is no longer an active inflammatory process. In this case, the applications could include pain reduction, assisting in warming up a joint for range of motion exercises, or helping relax muscle/tendon tissue for the sake of stretch.
For example, a patient may heat their calf muscle if they are looking to work on stretching the calf or performing active/passive dorsiflexion range of motion exercises.
Conclusion – Should you use heat or ice for an ankle sprain?
Overall, based on the current evidence and clinical experience, ice tends to be preferred for an ankle sprain, especially in the early stages of an acute injury when the inflammatory process is at its peak.
While evidence is controversial on the exact benefits of applying ice to ankle sprain, clinical outcomes appear to be better when using ice over heat, at least anecdotally. Benefits may include reduced pain, reduced swelling, and the possibility to reduce inflammation.
Heat can be used as well, but this is typically reserved for the later stages of recovery when we are trying to regain muscle, tendon, and joint flexibility in surrounding areas that may have stiffened up over the course of recovery. Benefits may include reducing pain, decreasing muscle and tendon sensitivity to stretch, and increasing extensibility of soft tissue.
Importantly, one should also consider that there are situations when the application of ice or heat therapy is inappropriate to apply to an injured area, for example, with circulatory conditions or bleeding and clotting disorders.
This, combined with the fact that the optimal selection of heat or ice varies depending on stage of recovery and desired effect, means that it is highly recommended to visit a doctor or physiotherapist when deciding to use heat or ice for your ankle sprain.
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The content here is designed for information & education purposes only and is not intended for medical advice.