Why do some people "recognize the bed" and cannot sleep?

? Many people who usually sleep well are not used to sleeping on a "new" bed when they are on a business trip, traveling or visiting relatives and friends. They tossed and turned and couldn't sleep at night. The Chinese often call this phenomenon "bed identification," and there's a reason for that. In the field of sleep research, there is also a term called bed recognition, or the first night effect. In other words, our bed recognition behavior can be explained scientifically.

? In fact, only half of people can sleep deeply in a strange place. What about the other half? They will create what we call the "first night effect," where our brains will be "on alert" to keep ourselves safe from unexpected potential threats. But now it is a harmonious society. What is the use of this protection mechanism? On the contrary, the other half of the people who "recognize the bed" do not get enough sleep, resulting in low work efficiency. Actually, don't worry too much. Generally speaking, this "first-night effect" protective mechanism is only apparent on the first day. After a night of familiarity, even we who know the bed can enter the deep sleep stage.

When we sleep, our brains go through a series of sleep stages, and we spend a different amount of time in each stage, as shown in the image above. When we sleep our deepest, it's in stages three and four (stages three and four in the diagram). During this phase, our brains produce very slow and synchronized fluctuations, and our body's recovery also occurs during this phase, because during this phase, proteins are synthesized and growth hormone helps our body recover and grow. In addition, our brain’s glucose levels are replenished at this time, and deep sleep is also very important for us to consolidate memories. As shown, we first spend more time in deep sleep and then move into lighter REM sleep. During the REM stage, we sleep lightly and are prone to dreaming.

A research team recruited a group of students to take part in sleep laboratory testing. EEG was used to record the brain waves of these students during their sleep for two days. The results showed that on the first night, the slow waves in the left hemisphere of the students' brains weakened significantly, and on the second night, the left brain waves adapted to the right brain waves, indicating that the students' brains had basically adapted to the new environment. The second experiment in the study involved a new group of students who were told that their headphones might emit a faint beeping sound while sleeping, but that they needed to ignore it. Most beeps are the same tone, but some are different and slightly different from the same tone. Generally speaking, the sleeper's left and right hemispheres respond to these different tones, showing brainwave waveforms. But the fluctuations are more pronounced in the left hemisphere, indicating that the left hemisphere is more sensitive to non-uniform noise than our right hemisphere. Similar to the previous experiment, the difference between the two hemispheres disappeared the next night.