Well while I'm not a professional in the topic in any way, I'd personally seen the benefits of walking in the cold (e.g. in winter where people were wearing man

Well while I'm not a professional in the topic in any way, I'd personally seen the benefits of walking in the cold (e.g. in winter where people were wearing many clothes on top of each other) with just a tshirt: it makes me feel much more alive, alert (in a good way, not in an anxious way), and much more immune to pretty much anything both physically and mentally.