When the body gets cold, it vasoconstricts blood vessels to push energy toward the core and insulate core organs, making the periphery colder.

“So for instance, if you were to stand next to a campfire or you were outside on a hot day, various things would happen to dump heat from your body. Now, what are those things? Well, there are a huge category of them. But the simplest way to think about this process is that when we get cold, we tend to vasoconstrict. Our blood vessels tend to constrict, and we tend to push energy toward the core of our body to preserve our core organs.”