Do you find yourself reaching for an extra cup of coffee so you can enjoy your first day of vacation? Well, it’s not just you—you really don’t sleep as well the first night in someplace new. In fact, this experience is so universal it’s called “the first-night effect.” Sleep even becomes so wonky that researchers typically ignore the data from the first night a test subject sleeps in the lab. Now we know why: According to new research from Brown University, half of your brain seems to actually keeps tabs on your safety.
For the study, published in Current Biology, researchers used advanced neuroimaging to view subjects’ brains while sleeping. This time, instead of throwing out data from that first night of sleep they examined it closely. They saw that instead of both sides of the brain resting, the left side was always a little more awake and responding to sounds around it.
Even if brains are wired to be hyper-vigilant, it doesn’t mean you’re doomed to groggy breakfasts on every trip. “Human's brains are very flexible,” Yuka Sasaki, lead study author, said in a statement. “Thus, people who often are in new places may not necessarily have poor sleep on a regular basis.”
For those who aren’t frequent flyers, Sasaki says bringing your own pillow or staying in hotels with similar accommodations each time you travel (e.g., the same chain) might help your brain to relax.
Have problems sleeping in your own bed, too? Your nighttime routine might be keeping you up. Here, five things you should never do before going to bed.