Heat vs Ice: What to use for Pain and Injury Management

Long Story Short!

  • Further research is needed for Cryotherapy (Icing), Thermotherapy (Heating) and Contrast therapy (Icing and Heating) protocols.

  • There is much anecdotal research on the proposed benefits of Cryotherapy and thermotherapy, but little scientific evidence on uses as a recovery method.

Ice Therapy

  • is effective as an analgesic (pain management) tool on localised tissue, especially with acute musculoskeletal injuries within the first 48-72 hours

  • inhibits muscular strength and performance therefore should be conducted after training or competition

  • combination with exercise therapy resulted in a greater restoration of muscular strength and reduction of muscle soreness

  • The 10minute protocol has proven to be the most effective Cryotherapy protocol

Heat Therapy

  • should not be applied within the first 48-72 hours of an injury.

  • has analgesic effects for sub-acute and chronic pain

  • applied with exercise rehabilitation proved significant with pain relief and function

  • is effective in increasing joint range of motion (ROM) and decreasing joint stiffness

  • may hasten the healing process of damaged cells

  • 10-20 minute applications of 40-45°C thermotherapy is the most effective form of thermotherapy

Contrast therapy

  • may improve the recovery process using a 3:1 or 4:1 ratio

Cryotherapy (icing) and Thermotherapy (heating) protocols are a major part of any rehabilitation or recovery process where inflammation and pain are present. The common response to any injury or pain is to apply ice to the injured site as per the RICER (Rest, Ice, Compress, Elevate, Refer) principle. However, it now appears that icing may not be as effective as believed in the healing process. Likewise, heat applications are another common method of pain management, but lacks clarity behind it’s therapeutic effectiveness. Of the scientific literature available, what evidence is supportive of icing and heating protocols for pain and injury management including post-exercise recovery?

Cryotherapy (Ice Therapy)

Cryotherapy is one of the most common approaches used to manage the initial phases of musculoskeletal injuries or post-competition/training recovery.(1,2) Cryotherapy can be achieved with the use of ice packs, ice baths, cold water immersion, ice massage or the more modern cryotherapy chamber. It’s aim is to minimise oedema and swelling through vasoconstriction and to reduce secondary hypoxic injury by lowering the metabolic demand of injured tissues.(1,3) More simply, cryotherapy aims to reduce pain which can restore, maintain or better function of injured or damaged pathological tissue.(4) The problem with cryotherapy is there is a distinct lack of clarity and evidence regarding its best use.(4,5)

There is anecdotal and clinical evidence that ice therapy has a temporary pain reducing and localized numbing effects.(6) Analgesic effects from ice therapy have proven to be effective in acute pain management and decreasing local cellular pathology for acute injury management.(7) Research suggests that icing may be effective in improving efferent activation of muscles, therefore dulling the effect of pain on motor patterning and performance.(6) On a cellular level, this analgesic effect from cold temperature will reduce the neuronal transmission rate which dampens the pain perception to the central nervous system.(8)

Ice therapy techniques reduce blood flow to an injured area, therefore minimising oedema, slowing haematoma development, and controlling cellular hypoxia and secondary metabolic injury. Whilst icing slowed oedema formation, it doesn’t reduce oedema that is already present. (9) There is no evidence that this will fasten the healing process. A summary of 22 scientific articles found almost no evidence that ice and compression hastened healing over the use of compression alone. (6) Although, ice plus exercise have been proven to marginally assist healing joint sprains. (10)

Spinal nerve impingement from lumber disc herniations can be managed with icing techniques to reduce swelling and inflammation around the irritated or compressed nerve which may be causing pain and discomfort.

There is limited information available on the appropriate application of ice therapy as a recovery method. In fact, it is reported that ice therapy does not speed recovery. (11) The assumption is that the benefits of ice therapy such as cold-water immersion will reduce inflammation in skeletal muscle. Little is known whether these treatments influence inflammation and cellular stress in musculoskeletal tissue after exercise.

A study conducted in 2013 required athletes to intentionally exercise at high intensely to cause extensive muscle soreness.(12) Although cooling delayed swelling, recovery speed was not increased from the muscle damage created. This study concluded that ice therapy delays recovery from eccentric exercise induced muscle damage.(12) On the contrary, a different study showed that cryotherapy was a useful tool for Delayed Onset Muscle Soreness (DOMS) and pathological damages.(13)

Furthermore, Yanagisawa demonstrated that ice therapy techniques in combination with exercise therapy resulted in a greater restoration of muscular strength and reduction of muscle soreness rather than ice or active recovery alone. (14)

Ice baths and cold-water immersion are common to post-recovery treatments as part of soreness or injury management.(15) Peake suggests that cold water immersion is no more effective than active recovery for minimizing the inflammatory and stress responses in muscle tissue after resistance exercise.(15) Prentice states that cold whirlpool therapy had a greater decrease in muscle soreness when compared to no treatment or a warm whirlpool. (13)

Although there is controversial, conflicting and a lack of evidence on recovery strategies, icing may have a placebo effect decreasing pain and soreness perception for post-training and competition recovery. This ‘fresh feeling’ can still have a positive mental effective for an athlete’s recovery process.

Muscular power and functional performance becomes severely inhibited after ice therapy treatments. (2,17,18) Ice Therapy techniques results in a reduction of muscular contractile speed and force generating capacity because of a decrease in neural transmission. (19) Evidence of performance being significantly impaired was apparent after an hour of cold water immersion therapy. (2) Therefore, it is appropriate that icing protocols should be applied at the competition of training or competition. (17,20)

The greatest effects of cryotherapy have been proven using an intermittent 10-minute protocol within the acute phase of injury (first 48-72 hours following injury). This protocol of applying ice for 10 minutes, then removing for 10 minutes, then reapplied for 10 minutes proved more effective than one 20-minute application in lowering tissue temperature and pain management. (21,22) The effects of ice therapy are reported to diminish after 15 minute applications due to the body adapting to the cold and responding by vasodilating blood vessels thus a return of normal tissue metabolism. (23) The 10 minute protocol is most effective when repeated every 2 hours, showing an enhanced analgesic effect and reduced the risk of adverse reactions such as burns and nerve damage when compared to a 20-minute on-off procedure. (19,22) Successful water immersion techniques include 20minute applications with heat out of water, in temperatures between 12-18°C. (24)

Thermotherapy (Heat Therapy)

Thermotherapy techniques are a common approach to pain management. Thermotherapy can be applied in the form of heat packs, saunas, paraffin baths, infrared lamps, ultrasound therapy or hot water immersion baths. The aim of heat therapies are analgesic, maximise the healing process, increase blood flow, soft tissue and joint elasticity and extensibility, increase neural transmission and muscle spasm reduction. (8,25) Simply, heat therapy claims to positively influence haemodynamic, neuromuscular and metabolic processes. But like cryotherapy, there is a lack of evidence and clarity regarding is most appropriate use.

Increasing skin temperature may reduce the sensation of pain, by altering nerve conduction or nerve transmission.(26) Several studies have demonstrated that applying heat over a site of pain or injury can increase the pain threshold. (27,28) A review found that heat therapy was effective in reducing pain and disability for patients experiencing 3 months or less low back pain. (29) The relief only lasted a short time, but further studies showed that in combination with exercise rehabilitation, the heat therapy provided additional benefits.

A different study showed that heat applied with exercise rehabilitation for patients with a duration of 3 months low back pain proved significant with pain relief and function. (30)

Thermotherapy may accelerate tissue healing by increasing circulation and enzymatic activity.(25) By increasing the circulation rate of blood flow to an injured site using heat therapy, a greater concentration of nutritious and oxygenated blood becomes available to the injured tissue.(10) This increase in blood flow increases cellular lymphatic and capillary permeability, which can increase the metabolism, nutrient delivery and removal of waste products from cells.(10)

Thermotherapy has the ability to increase metabolic reaction rate, allowing the inflammatory and healing processes to proceed more rapidly. (25) Increasing temperature of the blood also increases the dissociation of oxygen from haemoglobin, making more oxygen available for the processes of tissue repair.(25) This process may be inhibited through cryotherapy causing vasoconstriction and slowing blood flow to injured tissue.

It is important to understand an increase in circulation can increase oedema, thermotherapy should be applied after the acute inflammatory phase to avoid delaying and prolonging the acute stage of healing.(25)

Thermotherapy has been proven effective in increasing joint range of motion (RO