The goal during stress inoculation practices like cold exposure is to release adrenaline from the adrenals without a proportional release of epinephrine from the brain stem, aiming for calm alertness.

“the reason deliberate cold exposure works so well to do this is that it is pretty non-negotiable even if you really love cold showers or cold plunges or things that sort you're still going to get that elevated adrenaline and noradrenaline it's pretty much non-negotiable you know for the first 10 or 15 seconds that you get into a cold plunge or a cold shower you should fully expect yourself to feel stress and for your breathing to accelerate and then your goal is to try and anchor or control your breathing in that stressful environment the reason for doing this is that it's a practice it's a practice that's going to translate to a better ability to manage your internal State and therefore your thinking your cognition and your ability to make good decisions under stress”

“what you're trying to do at a mechanistic level is to have adrenaline released from the adrenals but not have adrenaline epinephrine released from the brain stem to the same degree so you're not just trying to buffer this you're not trying to say oh this is good for me this is good for me I'm going to grind this out you're not trying to grind it out you're trying to move through this calmly while maintaining alertness”