If you've ever traveled, you know that your first night in a new bed is often a sleepless one. That brain fog you wake up with feels like you've got five pounds of poop in a three-pound bag. The good news is there's a legitimate scientific explanation for why your brain won't shut down when you need it to.
According to researchers, what you're experiencing is something called the First Night Effect (FNE). It's a phenomenon where your brain doesn't sleep as well the first night in a new environment. When you lay your head down in a hotel or an Airbnb (or really anywhere that isn't your own bed), your brain essentially goes into threat-assessment mode.
The reason for this goes back to our evolutionary past. Animals need to stay alert when they're in unfamiliar territory, and humans are no exception. That's why people often sleep with their head as far from a doorway as possible — it's an old instinct.
One hemisphere of your brain literally stays more awake than the other when you're in a new place. This phenomenon is called Unihemispheric Slow-Wave Sleep, and it's the same thing that allows ducks to sleep with one eye open. That way, your brain can monitor for potential threats while the other hemisphere tries to calm the hell down and get some rest.
Previously:
