A recent study published in the journal Sleep found that wearing an eye mask overnight improves episodic learning and alertness. The researchers performed two separate experiments on 18 to 35 year-old study participants and found that wearing an eye mask to block ambient light improved both sleep quality and cognitive function the next day.

According to PsyPost, good sleep is vital for the healthy functioning of our brains and bodies. Too little sleep or poor-quality sleep negatively impacts our alertness during daily activities. Studies also show that ambient light is one cause of sleep disruption.

Study author Viviana Greco, from Cardiff University Brain Research Imaging Research Centre in the U.K., personally faced a sleep challenge when she moved to the U.K. and bought a home in Cardiff that didn’t have any shutters. Even curtains didn’t provide enough darkness so she found it difficult to sleep.

“We then became curious to know whether wearing an eye mask overnight to block ambient light could be an easy solution,” she said, referring to her fellow sleep scientists.

The first experiment involved a sample of 89 participants between the ages of 18 and 35. For the two-week experiment, participants spent five nights sleeping in their homes while wearing an eye mask. They were then given two days of cognitive testing. They then spent the next five days sleeping at home with no masks and were tested again.

In the second experiment, 33 men and women between the ages of 18 and 35 spent two nights with an eye mask and two nights wearing an eye mask with cutouts so that the eye region wasn’t covered, establishing a control group. The participants wore a digital light meter placed on their pillows while wearing an EEG headband to examine their sleep stages.

The results of the second experiment replicated the results of the first, finding better learning performance when participants wore a mask. Moreover, wearing a mask was associated with more time spent in slow wave sleep, which resulted in memory improvements. Slow wave activity restores the brain’s ability to encode new information, says PsyPost.

The study authors say that their findings have real-world implications since many people have sleep struggles at night and everyday activities require us to be alert and give rapid responses.

“Wearing an eye mask overnight can be an effective and inexpensive solution for improving and benefiting cognitive performance,” Greco told PsyPost. “Our results speak about improved reaction times and improved memory performance. The implications of our results are significant on many daytime tasks like driving a car or an educational or cultural context that requires learning.”