How many times has it happened to us that after going to sleep in a new place, be it the house of an acquaintance or a hotel, we could not sleep properly and we woke up almost more tired than we were? A team of researchers from Brown University in Providence (USA) has discovered why this happens.
According to experts, the first night we spend in another bed, for reasons that are unknown at the moment, there is a hemisphere of the brain, specifically the left, which is more awake and vigilant during sleep. It is what is known as the “First Night Effect” or more popularly as “sleeping with one eye open.”
“ One of the hemispheres of the brain stays more awake during sleep to keep watch . Sleep is often considerably worse during the first night in both a hotel and a sleep laboratory. In the latter context, researchers often have to plan an ‘adaptation night’ in their experiments, “says Yuka Sasaki, leader of the study.
Experiment
The researchers used advanced neuroimaging techniques in a group of 35 participants who had their brains examined in the sleep phase. The data revealed that the two hemispheres of the brain exhibited different activity patterns. Thus, the left hemisphere, in all the participants, was always the one that was in alert mode, the most awake.
According to experts, this asymmetry in activity was explained by the volunteers’ difficulty in falling asleep in the laboratory during the first night. This moment was critical since during the following nights that the experiment lasted, this differentiation of activity in the patterns of the cerebral hemispheres did not occur again.
A possible solution?
“The human brain is very flexible and eventually adapts to new situations,” says Sasaki. A possible solution would be to take something personal that is familiar to us and close to the room where we are going to sleep, such as our own pillow or to look for places that are familiar to us.
The study has been published in the journal Current Biology.





