This blog post contains general medical information and should be read as such. For personalised injury management advice, feel free to contact one of our physiotherapists to help you out.
When to use heat or cold therapy, or maybe both?
As a physiotherapist I often get asked the question:
‘What is better heat or cold, what should I use?
The answer on this question all depends on the situation and the type of injury.
Both cryotherapy (cold) and thermotherapy (heat) can assist in the management of musculoskeletal injuries, such as a sprained joint (rolled ankle, jarred knee) and strained muscles. Both thermotherapy and cryotherapy can reduce pain and muscle spasm, but to determine what to use, and when, it is important to know what the effects of applying heat and cold are.
So, whilst both heat and cold reduce pain and muscle spasm, in regards to the tissue metabolism, the blood flow, inflammation, swelling and tissue flexibility the effects are opposite.
Both heat and cold therapy reduce pain and muscle spasm by activating thermoreceptors, special temperature sensitive nerve endings. Activation of these thermoreceptors can block the signals from nociceptors. Nociceptors are nerve endings that are activated in response to tissue injury. The signal from these nociceptors travels through our nervous system to the brain where the can be perceived as pain.
So, by blocking these signals, we can block (or reduce) pain. At the same time, following an injury, signalling chemicals (neurotransmitters) are released that set of a reflex that makes the muscles in the area tense (spasm). Increased muscle tension reduces the blood flow in a muscle, which results in an oxygen shortage (hypoxia) in the muscle, this subsequently results in more pain. Potentially this can result in a self-reinforcing cycle of pain à muscle tension à more pain.
Cold therapy reduces local blood flow as well. This has the potential to supress the inflammatory response following an acute tissue injury and can reduce swelling this way. For this reason, it is useful in the management of acute tissue injuries, such as rolled ankles and sprained knees.
Caution must be exercised when applying cold therapy, as there as some negative side effects (for example frost bite, nerve irritation, reduced wound healing) if not applied correctly.
Heat therapy has the opposite effect on local blood flow, it increases it. Increased blood flow has the potential to facilitate healing by increasing the supply of proteins, nutrients and oxygen to the site of the injury. Heat therapy also increases the extensibility (flexibility) of local soft tissue (e.g. muscles). Caution should also be exercised when using heat therapy, particularly in those with poor circulation, diabetes or rheumatoid arthritis.
When to use it?
As a rule of thumb: use cold therapy in the early management of any acute injury where signs of inflammation (swelling, increased tissue temperature) are present; use heat therapy for muscle pain or stiffness.
If the injury is not acute, and no contraindications are present, both heat and cold therapy could be indicated. Important considerations here are the amount of pain, the degree of muscle spasm and personal preference. Generally cold therapy is used in cases of severe pain and muscle spasm, but the preference of the individual is most important! Cold therapy reduces mobility, so should not be used for persistently stiff joints or muscles.
How long for
Use cold therapy for no longer then 20 minutes at a time and use it several times a day.
Heat therapy, opposed to cold therapy, can be used for a longer time frame, up to two hours if desired (for example lying in a hot bath).
Contrast therapy uses cold and heat therapy in an alternating fashion. Contrast therapy is used by some to speed up the recovery following exercise, or injury. The evidence supporting the use of contrast therapy is, at this stage, lacking. The idea of contrasting heat and cold is to increase / decrease blood flow and metabolic tissue activity. This ‘pumping mechanism’ is thought, by some to speed up recovery following exercise and injury. Current research findings however show little benefit of alternating heat and cold. This of course doesn’t mean that it doesn’t work for some and could be worth a try for the individual to determine its efficacy.
When selecting what to apply, heat / cold / contrast, the first consideration should always be the presence of any contraindications. If neither heat or cold are contraindicated, and the condition is not acute, personal preference maybe one of the most important factors to consider.
At Aspire Physiotherapy Bunbury, we utilise both heat and cold therapy. PowerPlay is a unique system which combines both compression and cold therapy and can be a valuable addition to your acute injury, or post-operative, management. Contact Aspire Physiotherapy Bunbury for more information, or to try out our PowerPlay system.