I think this article is about the Wim Hof Method, although the site's design kept me from reading it. I've done a workshop with a WHM instructor, and for anyone wanting to try it, there are three key points I would say. (Note, that I am not an instructor myself, I've only done one workshop and practiced myself.) This works not just when going swimming in cold water or taking an ice water dip, but also in cold weather when you're not dressed warm enough to be comfortable.
Deep breathing. Not slow, but full and continuous inhaling and exhaling to the boundaries of lung capacity.
Physically and mentally relaxing. Shivering is a way to generate heat through motion. To counter it, and stimulate chemical heat generation, relax all the muscles. To relax mentally, something like breath meditation.
Mental/visual. Imagine being warm, like on a hot beach laying on the sand.
Hope this anecdata helps someone. I wouldn't count on it replacing warm clothes, but it's nice in a pinch.
Deep breathing. Not slow, but full and continuous inhaling and exhaling to the boundaries of lung capacity.
Physically and mentally relaxing. Shivering is a way to generate heat through motion. To counter it, and stimulate chemical heat generation, relax all the muscles. To relax mentally, something like breath meditation.
Mental/visual. Imagine being warm, like on a hot beach laying on the sand.
Hope this anecdata helps someone. I wouldn't count on it replacing warm clothes, but it's nice in a pinch.