Although cryotherapy has been used since ancient times via the application of ice to a swollen or injured area.  Ice packs have been used for centuries and malleable frozen packs have been used for decades.  Cuffs containing refrigerant that wrap around areas of injury have been employed for the past 30 years.  But only in the second decade of the 21st century has whole body cryotherapy (WBC) become a fad.  A person is immersed in a tank cooled by liquid nitrogen to minus 140-180 deg F for 2 minutes.  Immediately upon exposure to these temperatures, the skin temperature drops by 20-40 degrees F, and it is theorized that it reduces pain, swelling, and inflammation. One study found a very temporary increase in antioxidant effect after whole body cryotherapy (Rheumatol Int. 2017 Sep;37(9):1481-1487). Some studies show improvement in inflammatory markers and "oxidative stress" immediately after a 10 day course of whole body cryotherapy treatments, but failed to followup with testing beyond the 10 day period, incorrectly concluding WBC prevents heart disease (Mediators Inflammat 2018 Feb 1:2018:8592532).  A review of effects found very modest if any at all measurable biochemical marker effects from whole body cryotherapy but there frequently is a reduction in pain and soreness (Front Physiol. 2017 May 2;8:258). One study found WBC actually worsens muscle function after marathon training calling into question the benefits of WBC after sports (Eur J Appl Physiol. 2018 Jan;118(1):153-163).  Fibromyalgia may temporarily show symptom improvement after 10 sessions of WBC over 8 days with improvement lasting up to one month.  It is not clear if these were merely statistical improvements or were actual clinical improvements in outcome (Complement Ther Med. 2018 Feb;36:6-8).  These liquid nitrogen centers are found around the US now and have been ruled a "non-medical device" by the FDA, therefore are NOT FDA APPROVED.  The FDA published a consumer update in July 2016 saying it had not found any evidence the “so-called treatment” can treat many of what stand-alone businesses claim cryotherapy can do.  Frequently chiropractors and non-medical owners of these devices are advertising these as healing devices with a large variety of unsubstantiated claims. Although there are few studies on cryotherapy as a medical benefit, many claims are being made about the miracles of cryotherapy.  Currently it does not appear to be covered by insurance.  There are some studies of whole body cryotherapy after exercise that show positive benefits such as reduction in vertebral pain in men but not in women (Wiad Lek. 2017;70(3 pt 2):543-546.), but another study suggests these effects are placebo effects (Eur J Appl Physiol. 2018 Jan;118(1):153-163). The safety of cryotherapy is unknown and there is at least one reported death from whole body cryotherapy in Nevada in October 2015 from suffocation (as reported by the New York Times Nov 5, 2015).  There are no significant safety studies that have been performed, and there have been incidents of an abdominal aortic aneurysm dissection after 15 sessions of whole body cryotherapy (Clin J Sport Med. 2017 Sep;27(5):e67-e68) and global amnesia after whole body cryotherapy (BMJ Case Rep. 2017 Oct 13;2017.)  Two MSU athletes were injured during whole body cryotherapy as reported in the Springfield News-Leader Jan 25, 2018.  Frequently, blood pressure is not checked by the operators of cryotherapy machines- this can have tragic results since the BP increases dramatically on exposure to the cold, potentially rupturing undiagnosed brain aneurysms (common) or causing heart failure. There is one study that shows exposure to -40 deg C (achievable without nitrogen use) plus convection currents is more effective than currently available commercial nitrogen units, therefore these expensive investments by chiropractors and entrepreneurs may soon be obsolete (J Therm Biol. 2017 Apr;65:138-144).

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Another type of cryotherapy includes cold water immersion.  This method has been used by athletes for many years for the same purpose, also without much in the way of scientific documentation.

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