Why you sleep better in your own bed
Posted April 28
Updated April 29
New research shows why we feel groggy while traveling even if we're in the same time zone. It's because our brains refuse to shut down completely when we're in a strange place; they stay half-awake all night, protectively scanning for danger.
This is useful if we're sleeping without a tent in a jungle or desert, not so much if we're tucked in safely in a nice hotel. Unfortunately, the phenomenon, called "the first-night effect," affects all aspects of sleep. When we're in a strange bed, it takes longer to get to sleep, we wake up more often, and we spend less time than usual in deep sleep, the lead author of the study, Masako Tamaki, told Smithsonian magazine.
To document what happens on the first night we travel, researchers monitored volunteers who spent two nights in a lab hooked up to instruments that measure activity in the brain. They found that the sleepers were more likely to be disturbed by even slight sounds on the first night than the second, showing that the brain continues to analyze threats even as we sleep, Jerome Siegel, director of the Center for Sleep Research at the University of California Los Angeles, told Smithsonian.
“If something unusual happens — if a door opens or you hear a key in a lock — you can alert to that, even though the intensity of the stimulus is quite low," Siegel said.
Smithsonian reporter Adam Hoffman noted that researchers have seen similar patterns in animals, including birds, dolphins and beluga whales.
"In dolphins, for example, at least one brain hemisphere remains entirely awake and vigilant at all times, allowing the other half to safely descend into deep sleep," Hoffman wrote.
(The phenomenon also exists in literature. Readers of Hugh Lofting's children's classic "The Story of Doctor Doolittle" might recall that the fantastical pushmi-pullyu had two heads, one of which would sleep while the other kept watch.)
While the first-night effect can be useful if you and your family are spending a night on the savannah, it can make for a poor start to a long-awaited vacation by making you start the trip tired.
To counter the effect, Hoffman suggests we may be able to "tone down the bark of our neural watchdog" by bringing along familiar items from home. (This is easy for the third of British adults who admitted to Travelodge in 2010 that they sleep with stuffed animals.)
To be safe, however, build in an extra day to recover. “If you have some important event, it’s better to not arrive the day before so you don’t have to suffer from the first night effect," Tamaki said.