Best of luck in Lake Michigan on NYE.I had done it for a year and a half. I did it along with regular meditation, but have gotten lax on both for the past 6 months. I still take a cold shower every morning and I do feel good afterwards. I have also done 1 ice bath and it felt good for me, painful initially. I also intend to hop in Lake Michigan on New Years and stick it out as long as I can. I missed doing it last year as I had Covid, but maybe should have anyway.
The breath work started to feel like work for some reason, and I decided to take a break. I was trying to get longer hold times instead of just freeing my mind. I however will say when I was doing it regularly, I had a feeling of calm afterwards.
I'm pretty sure between meditation and the breath work my resting heart rate dropped noticeably. I was in the high 50's to low 60's, and after doing both for awhile I was hitting the high 40's and low 50's regularly. The nurse at last year's physical took my pulse 3 times as she was surprised it was 52 in the middle of the day.
I still do cold showers, even in Winter. No ice Lakes where I live. After a few years you get used to it. Summer can be worse than Winter if the water is cold and your Body is used to warmth.
Little tricks like start on the Legs and Butt before immersing Chest n Back etc. Flex the core to keep heat around the vitals.
First few times are such a buzz afterwards. They say it builds emotional durability, but so would a kick nuts too probably.


He's a year younger than I am, but looks older. In addition to what tango29 said about sun exposure, there's also the function of genetics. Not everyone ages in the same way. Doesn't mean you don't play the hand you're dealt as best you can.