Seems like a lot of people are moving on from the classic ice pack, to this trendy technique called cryotherapy, which offers whole body immersion in chambers where temperatures drop to 150 degrees below zero for about 2-4 minutes in an attempt to reduce pain and speed recovery.
The idea sounds great! The important question always is, what does the research behind it say? Similar to ice packs and ice baths, cold therapy is thought to constrict blood vessels, flush waste products, reduce swelling and diminish tissue breakdown. It definitely lowers superficial tissue temperatures- it doesn’t penetrate the skin’s surface more than 1/2mm into the skin. A possible explanation for this is that cold slows down the speed at which nerves fire, while constricting arteries and veins, and limiting blood flow. The idea that cold can heal is ancient, but so far, scientists have failed to find strong evidence that cold therapies can help much, if anything with muscle soreness or recovery.
Some studies even suggest that icing dampens or block the body’s ability to repair and strengthen the micro tears in muscle tissue following intense exercise, especially if people use ice too frequently. Trauma to the muscle caused by intense exercises is healed by your immune system using inflammation. Inflammatory cells called macrophages rush into the injured tissue to start the healing process and release a hormone called IGF-1, which helps your tissues heal. Applying ice reduces the swelling, delays healing and may PREVENT the body from releasing these hormones.
At this point there is insufficient evidence to warrant making clinical claims about its effect in speeding recovery. There are instances in which delaying the inflammatory process might be beneficial, for example in a multiple day competition, where inflammation, swelling and pain would be detrimental for your performance. Despite the fact that there is insufficient evidence to prove how it works or why it works, cold therapies do seem to help especially with pain reduction, but their effect might be based in the brain and not the muscles.
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Purnot, H., Biuezan, F., Louis, J. et al. (2011). Time-course changes in inflammatory response after whole-body cryotherapy multi exposures following severe exercise. PloS ONE. 6(7): e22748. Doi:10.1371/journal.pone.0022748
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