NB: We DO NOT recommend the use of an ice bath as a matter of course; or without a professional consultation.
As a rule of thumb, you should apply an ice pack as soon as possible after an injury; applying it for 10-15 minutes, and repeating after 60-90 minutes. Make sure that the ice pack is dry, and covered in a layer of material. The closer you can stick to this regime the better.
After the 3rd or 4th day, then it becomes a little less clear as to which you should use. Generally after this time, muscles will respond better to heat, whilst joints will respond better to ice. If you’re unsure, try alternating between the two. Apply ice for 10 minutes, then 45 minutes later, heat for 10 minutes; repeating this cycle.
How It Works:
Heat: Directly stimulates sensory nerve fibres, altering your perception of pain, by overloading the sensory pathways. Heat also increases the metabolic rate of the tissue, increasing the efficiency of what they’re doing at the time - namely, trying to heal the injury. Heat can also directly increase flexibility of tissue, resulting in relief from muscle spasm, and increased range of motion.
Heat may exacerbate bleeding &/ oedema locally. Possible side-effects include burning if too hot.
Cold: Applied for up to 5 minutes, produces vasoconstriction, which will help to reduce bleeding and oedema in the early stages of healing. If applied for more than 5 minutes (but less than 15 minutes), cold has the opposite effect, improving the local blood flow; but then, by removing the ice, the body's own regulation systems will immediately warm the area, exciting the cells, who can then use the extra blood supply provided.
These vascular effects last longer after ice than they do after heat therapy. Ice also has an analgaesic effect through stimulation of the some of the sensory nerves (similar to heat), combined with reducing the conductivity of the pain sensory fibres allowing some pain relief.
If overused (more than 15 minutes per application, or more used frequently than every 60 minutes or so) then the use of cold therapy will slow down the healing process.
Possible side-effects include an ice-burn if used inappropriately (ice-pack not wrapped in dry tea-towel).