Human beings learn to regulate their body temperature by being exposed to it. They're out in the cold without clothes because that's their choice. When their body is past its ability to stay warm, they'll ask for clothes. We check in with them and have warm clothes available for them when this is going on. We also have learned from other cultures that live in much colder climates to watch for the second shiver. The thinking is that the first one is the body relaxing into the cold as it warms up and the second one is the body shivering to create more warmth than it can from simply relaxed breathing. This tracks with my experiences in the cold.
Cold exposure is necessary for thriving. In the US, there's a culture of fear of cold exposure. It helps build up immunity and simply the basic operation of self-regulation.
Years of depending on clothes and machines to regulate our body temperatures seems to be leading to less resilience, not more.