system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do my feet get cold and sweaty when I don't wear socks and have them underneath the blanket? 

This can't just happen to me...
gpt
When you first get under the blanket your body begins to heat up, as it no longer has to work as hard to stay warm. As a reaction, it expands blood vessels near the surface of your skin to shed extra heat. The only problem is most of that heat gets trapped under the blanket. When your body registers that it isn't cooling off it kicks on the sweat glands. This is why a lot of people sweat during sleep.

As far as your feet go, it could be you're not used to noticing your feet sweat when you're walking around during the day, but at night it becomes noticable. If only your feet are under the blanket, it's probably because of the temperature difference. Your feet are trying to cool off while the rest of your body has to work to stay warm.