A new finding shows that only half of your brain is asleep when you are sleeping in a new place (such as a hotel or a friend’s house), while the other half of your brain seems to stay awake. This finding was published in the Current Biology journal on Thursday and explained why this happens.
When sleeping in unfamiliar settings, the left side of the brain stays awake as if it is “standing guard.” This explains why we tend to feel exhausted after sleeping in a new place. Sleep specialists and researchers discovered this phenomenon, called the “first-night effect” a few decades ago when they started studying people who participated in sleep labs. The first night in the sleep lab was usually so bad for most of the participants that researchers could not use the data from that night. They wanted to know why this was happening.
Yuka Sasaki, an associate professor of cognitive, linguistic, and psychological sciences at Brown University, and a team of researchers studied the sleep and brain wave patterns of over 30 Brown University students. The team monitored each participant’s “slow-wave activity,” a pattern that occurs during deep sleep. The team found that during each student’s first night of the experiment, there was a greater slow-wave activity in the right hemisphere of the brain than there was in the left hemisphere of the brain. On the following nights, both hemispheres had great slow-wave activity.
The research team also conducted a sound test to see if it really is the left side of the brain that remains awake. They played sound that was loud enough to wake a light sleeper. They found that participants woke up faster when the sound was played into their right ear, which is connected to the brain’s left side.