When you sleep in unfamiliar surroundings, only half your brain is getting a good night’s rest.
“The left side seems to be more awake than the right side,” says Yuka Sasaki, an associate professor of cognitive, linguistic and psychological sciences at Brown University.
The finding, reported Thursday in the journal Current Biology, helps explain why people tend to feel tired after sleeping in a new place. And it suggests people have something in common with birds and sea mammals, which frequently put half their brain to sleep while the other half remains on guard.
Sleep researchers discovered the “first-night effect” decades ago, when they began studying people in sleep labs. The first night in a lab, a person’s sleep is usually so bad that researchers simply toss out any data they collect. (Source)