A group of psychologists and sleepologists from Cardiff University in the UK found that wearing a sleep mask improves cognitive function the next day. The results of the study were published in the journal Sleep.
The study involved 89 volunteers. During the week, participants spent 5 nights wearing an eye mask and then took part in a 2-day trial. During the second week, the experiment was repeated, but without a mask.
The researchers found that participants performed better in learning on the word pair association task after sleeping with the mask on. They also performed better on the psychomotor vigilance test, which measured behavioral vigilance and sustained attention. Taken together, this suggests that the mask helped improve participants’ cognitive abilities.
Interestingly, the participants’ sleep diaries did not reveal any difference in sleep hours or sleep quality scores between the two weeks.
The second experiment involved 33 people. This time, participants slept for two nights with an eye mask and two nights with a similar mask, but with cutouts. At this time, scientists collected EEG data from the brains of volunteers.
“Higher learning efficiency after wearing the mask was associated with a longer period of non-REM sleep, which increased due to the fact that the eyes could not catch the light,” the scientists explained.