Nino,
These are very interesting findings!
I have a few thoughts in response:
1. The reduction in muscle soreness and improved recovery could be due to induced testosterone, but it could also be explained by other factors. One very simple and likely explanation is that cold water reduces inflammation, which is why cold compresses are often used by athletes. There may be additional effects, and if could be a combination of factors.
2. I've experienced the same cold tolerance effect that you describe. The more cold exposure, the greater the tolerance. There is evidence that cold exposure increases adiponectin levels and stimulates the growth of brown fat (BAT), which helps with thermoregulation and cold tolerance. [See the earlier discussion in
this post]. Other explanatory factors could be neurological adaptation (receptor and neurotransmitter rebalancing) along the lines of the opponent-process theory of emotional/sensory adaptation. Without controlled experiments, its hard to know the relative importance of these different potential causal explanations. But we can at least acknowledge that tolerizing adaptation to cold does occur, even if we can't say for sure what drives it.
3. The ice water chugging idea is something that Tim Ferriss advocates in the Four-Hour-Body. (Perhaps that inspired you to try it?). I haven't tried that myself yet -- perhaps I'll try. I do drink quite a bit of water, either as plain water or in dilute herb teas, but it is generally room temperature, warm or hot. I'm wondering whether the appetite suppressing effect you experience requires that the water be quickly chugged down -- or whether you could sip it over 5 or 10 minutes and get a similar effect. I'm a bit hesitant to do a lot of rapid chugging, unless that is important.
Thanks,
Todd