The Nrf2 system, which controls antioxidant response elements, can be stimulated by cold exposure, fasting, and exercise.

“we know this is exactly the same thing that's happening with the cold water swimmers and there's other good research showing that exercise effects nrf2 heat effects nrf2 we know that cold does with the berlin cold water swimmers and ketosis can also affect the nrf2 system and the liver nrf2 is a transcription factor in the liver the turns on genes involved in oxygen response generally up regulates glutathione levels so that we can do more molecular policing of free radicals in the human body”