Why do chills/goosebumps form immediately after contact with heat (e.g., getting into a hot shower or a car on a hot summer day)?

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Why do chills/goosebumps form immediately after contact with heat (e.g., getting into a hot shower or a car on a hot summer day)?

In: Biology

Well, what would be the advantage of waiting? The job of goosebumps is to trap an insulating layer of warm air around the skin by raising the hairs into a kind of mesh structure, similar to how foam insulates. We’ve lost most of those hairs, so this doesn’t work anymore, but what would the evolutionary benefit be of delaying the goosebump response? It hasn’t been delayed in humans because it doesn’t do anything, so there’s no difference between whether it happens immediately or happens after say, 37 seconds.

As for “chills”, if you’re talking about why it feels so cold after a hot shower, this is because you’re stepping from the hot, humid air of the shower to the dry, room-temperature air of the rest of your house, and your body is covered in a layer of water. This water behaves in the exact same way as sweat: It evaporates easily into the dry air, taking some of the heat energy inside you with it when it does so. This isn’t something the body can evolve to do anything about, it’s just an unfortunate consequence of being wet in a dry room.