We’ve covered a lot, so I think now is as good of a time as any to take a step back and ask what’s the big picture message here. In other words, what does all of this mean? I think there’s many key take homes from all of this. I’ll try to summarize just a few.

  • ONE. Cold shock shows some interesting promise for helping diseases of neurodegeneration through a special cold shock protein known as RBM3… will we be taking people and putting them through super traumatic freezing temperatures in the future to prevent Alzheimer’s? I don’t know, but the fact that this neuroprotective, synapse fixing effect happens in mice is a very good sign and hints at some really profound things we may find out in the future are applicable to humans as well.
  • TWO. Norepinephrine, which can go up a huge amount from a variety of different cold stressors, has some pretty interesting properties and is a very versatile neurotransmitter and hormone! We need it for vasoconstriction, as part of our body’s dynamic response to cold, but it is also anti­infammatory. For this reason it may have special relevance for diseases of inflammation, like arthritis, as well as mood and even depression.
  • THREE. Giving yourself short bouts of intense cold stress may be applicable if you have some degree of chronic pain, because of the analgesic effect, which may also be partly mediated by… you guessed it… norepinephrine.
  • FOUR. There may be some truth to winter swimming improving immune function in regular practitioners.
  • FIVE. In contrast to old dogma, adult humans have brown fat and exposure to cold increases it. Brown fat generally decreases as we get older, especially if we’re obese. Having more of it, however, is associated with trending towards a lower body fat percentage, and, finally, the amount of brown fat is directly affected by our exposure to cold. Cold­water immersion can definitely increase brown fat, but so can cold air, which means whole body cryotherapy is probably also effective for this purpose.
  • SIX. Using cryotherapy and cold­water immersion in the context of exercise is sort of complicated! You can definitely undermine your gains in the context of resistance training if you’re doing cold­water immersion immediately after training. In other contexts, however, there may be improvements as well. We still have some unanswered and very interesting questions surrounding this. I’m hopeful that the more deleterious effects will turn out to be mostly constrained to the hour long window of time immediately after training, but I’m not really sure. We need more studies to say for certain!
  • SEVEN. When comparing whole­body cryotherapy and cold­water immersion, they are are probably pretty similar… at least in many of their hormonal responses. One key point of difference is that it is possible to stay in cold water for a longer period of time than it is to stay in a cryotherapy chamber, which could put you in danger of local tissue damage, such as frostbite. Do what strikes your fancy until better evidence emerges. Cautionary Note It is prudent to consult a physician before beginning a new workout program, and this is no less true for activities like cold­water immersion, winter swimming, or cryotherapy. This document is for informational purposes only and not medical advice. Use this information at your own risk.

Additionally, if you have coronary risk factors or other heart related risk factors, it is especially important that you consult a medical physician before attempting anything discussed in this article, but, perhaps, especially before doing contrast therapy (going rapidly from very hot to
very cold).