Ice versus Heat: when to use which?

“When do I use ice or heat?” – this is one of the most common questions patients ask during their therapy sessions. Is it as simple as ice for acute injury and heat for chronic injury? This blog post will help you to gain a clearer picture of the difference between ice and heat and when to use them to optimise your training and recovery from injury.

Physiological effects of ice and heat

Both icing and heat have been used as a treatment to reduce pain, with the main difference being the different phases of healing in which they should be employed. 

Ice

The use of ice has traditionally been employed during the management of acute injuries as a way to reduce inflammation and speed up healing. This was emphasised through the R.I.C.E (Rest, Ice, Compress, Elevate) protocol. However, over the years, research has caused a paradigm shift to a PEACE & LOVE protocol where there is a conspicuous absence of icing.

peace&love

Studies are increasingly showing that inflammation kickstarts the healing process by releasing hormones that remove damaged cells. Inflammation is therefore beneficial in the acute phase of injury and icing might prevent this release of hormones and delay healing.

So should we stop using ice in the acute phase altogether? Well, the answer is that it depends. Ice can still be used to reduce swelling in the acute phase. Excessive swelling creates unnecessary pressure on the tissues, causing more pain and preventing motion. Reduction of swelling can allow the patient to move more comfortably, which improves healing.

Heat

Heat works by causing blood vessels to dilate, which improves blood circulation to the tissues. This is why it is often avoided during the acute phase of tissue injury as it might cause more swelling. Instead, heat is employed as a way to improve muscle extensibility by causing the muscles to relax. Hence, it is especially effective when pain is associated with stiffness. The increase in blood flow to the area also helps to speed up the removal of waste products, thereby allowing faster recovery.

What should I use after exercise?

The use of ice as a post-exercise treatment has been popularised through its use by professional athletes. It is touted as an excellent way to prevent delayed onset of muscle soreness (DOMS), the discomfort in muscles post intensive exercise. However, the research on this only shows that icing is superior in alleviating the symptoms of DOMS compared to sitting, standing or lying down post-exercise.

On the other hand, another study comparing the effects of ice versus heat on post-exercise recovery showed that icing slows down the recovery of muscle strength and fatigue resistance, which can impair subsequent exercise performance. In contrast, heat accelerates the recovery of muscle strength and fatigue resistance. 

With there being no consensus in the research thus far, it seems to be dependent on the situation the athlete finds themselves in. If they are participating in competitions where they take part in multiple matches within the same day, ice might not be the best way for them to recover in between matches.

A summary on when to use ice vs heat

So, what does all this information mean to you? The table below provides a rough guideline of when to use ice or heat.

Pain

Ice if swelling is the cause of pain

Heat if stiffness is the cause of pain

Swelling Ice – 10 minutes on, 10 minutes off with application of compression, then reapply ice for 10 minutes
Muscle strain Heat
Joint sprain

Acute stage – ice if swelling is limiting the range of motion

Chronic stage – heat to improve circulation and reduce stiffness

Nerve pain No scientific consensus
After exercise No scientific consensus
Before stretching Heat to improve muscle extensibility

Method of application

For icing, a crushed ice and water mix in a plastic bag is more effective than instant cold packs or cold sprays

For heating, heat packs are the most common method. In the absence of heat packs, hot towels or hot baths can be substituted. Deep heat ointments or packs do not penetrate deep enough into the tissues.

For both ice and heat, do not apply directly onto the skin to prevent burns from happening. Always put a layer of towel on top of the skin first.

Conclusion

Ultimately, movement, as soon as it is possible, is what will speed up recovery. Both ice and heat are adjuncts to help you return to movement quicker by reducing obstacles such as swelling, pain or spasm. 

Leave me a comment below and let me know what you think of this post!

Background research

(https://www.running-physio.com/ice/)

https://www.physio-network.com/blog/ice-for-acute-injury/

  • Started with RICE protocol by Dr. Gabe Mirkin to minimise the inflammatory response in an attempt to accelerate healing.
  • Consensus throughout literature that ice acts as a great analgesic by cooling the skin’s temperature.
  • Impact on underlying muscles is non-existent, as muscle temperature remains unchanged from topical ice application.
  • Uncertain about healing properties of ice.
  • However, current research highlights the necessary benefits of the inflammation process. With inflammation, the hormone insulin-like growth factor (IGF-1) is released to kill off damaged cells and initiate healing.
  • Therefore, ice might actually prevent this release of IGF-1 and delay healing.
  • Progression from RICE to PEACE & LOVE over the years, ice was removed.
  • So should we stop using ice altogether?
  • Too much swelling is still bad → unwanted pressure on tissues, restricts movement, increases pain and decreases muscle function.
  • Ice can be used to reduce swelling with the goal of allowing the patient to move more comfortably, which improves healing.

https://www.tandfonline.com/doi/full/10.1080/23328940.2017.1413284#:~:text=Cryotherapy%20is%20a%20popular%20method,immersion%20of%20the%20exercised%20limbs.

  • Cryotherapy is a popular method used by professional athletes, which is assumed to improve post-exercise recovery recovery of skeletal muscle function.
  • Post-exercise of muscle strength and fatigue resistance following endurance exercise is worsened by cooling, whereas muscle heating accelerates recovery processes.
  • Given that muscle glycogen resynthesis is most rapid within the first few hours immediately post-exercise, using cold water immersion particularly within the immediate post-exercise time frame may worsen skeletal muscle recovery and impair subsequent exercise performance in sporting events where multiple competitions or qualifying rounds are performed within the same day.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4586380/

  • One main finding of this study was that cold therapy significantly alleviated the symptoms of DOMS 24hrs, 48hrs and 96hrs after the cooling application. 
  • Cooling did not affect objective recovery variables such as lactate levels, CK levels or IL-6 levels. 
  • Cooling is superior compared to passive recovery strategies after various exhaustive or muscle-damaging exercise protocols.

https://www.physio-pedia.com/Thermotherapy

  • Heat increases blood flow by vasodilation. The metabolic rate and tissue extensibility will also increase. Heat increases oxygen uptake and accelerates tissue healing. It also increases the activity of destructive enzymes and increases the catabolic rate.
  • Heat results in muscle relaxation and a decrease in muscle tone.