Does ice really reduce swelling and speed up healing?
I am intrigued by the constant use of ice packs for all manner of things including sports injuries, post surgical healing such as knee and hip replacements. However I have never been able to find any convincing scientific evidence that there is a rational basis for the use of ice.
What I know about the application of ice is that cold constricts blood vessels and that, post cold-application, the blood vessels enlarge to flood the area with blood. I fail to understand why the intermittent use of ice will reduce swelling or speed up healing.
We posed this question to Dr Jonathan Leeder, Physiologist at the English Institute of Sport.
Jonathan - Soft tissue injuries such a contusions, strains and sprains are frequent in multiple human endeavours and ice is commonly applied as part of the PRICE principle which stands for Protection, Rest, Ice, Compression, and Elevation. Ice is generally applied immediately post injury to reduce tissue metabolism thereby limiting secondary hypoxic damage and reduce the degree of oedema and muscle damage. Although this holds credited scientific rationale there is very little empirical evidence to support the use of ice at this stage.
Hannah - So, ice cools injured tissue down, lowers its metabolism and it's thought that this decreases the chance that the swollen tissue becomes starved of oxygen, and further damaged. Anything else?
Jonathan - The second common use of ice is in the rehabilitation stage - primarily due to the analgesic properties of ice application. The efficacy of ice application for analgesia, largely due to reductions in nerve conduction velocity is well-documented and supported by reasonable evidence base.
Although ice may be capable of reducing the painful symptom associated with soft tissue injury, there's limited evidence to suggest that the application of ice enhances the recovery rate of injury rehabilitation. It may just alleviate soreness during your recovery process.
Conversely, there's probably a growing evidence that suggested, it might actually be detrimental to attempt to reduce the inflammatory response through ice application because inflammation is a critical part of the repair process.
In summary, due to the proven analgesic properties of ice application, it does have a place in acute soft tissue management but due to lack of evidence in high quality research optimal protocols are not known.
Hannah - So, ice is known to be useful at stopping pain and it does this by lowering the speed that nerve cells send their electrical signal. Decreasing tissue temperature with the ice may also slow down the rate of production of inflammatory factors. And this will include some noxious pro-inflammatory metabolites that will sensitise nerve endings to pain. So cutting down the inflammation will cut down pain this way too. But the downside of this is that ice may also be slowing down your body's immune system and therefore, preventing your body from repairing itself.