Let more light into your home and you can lower your anxiety and stress levels and even improve your sleep. Increasing daylight in a home can affect a person’s circadian rhythm, sleep, vitality, and mental health, according to a newly published, peer-reviewed paper in the International Journal of Environmental Research and Public Health.

“The study demonstrates the impact of daylight on the physiological, behavioral, and subjective measures of circadian health in a real-world environment,” says Mariana G. Figueiro, senior author of the paper. “The findings highlight the importance of ensuring people are exposed to circadian-effective electric light or daylight indoors as well as outside for human health and well-being.”

Light-to-dark cycles are important for circadian rhythms, the internal process that controls sleep. As more people spent time at home during the pandemic, the importance of balancing this may have become even more important, researchers note.

The study, conducted by the Light and Health Research Center at the Icahn School of Medicine at Mount Sinai in New York, shows “smart windows,” electrochromic glass windows that tint dynamically based on the location of the sun, may help filter the light better than blinds and window shades, offering a boosted psychological benefit.

In the study, researchers tracked participants first in homes with smart windows and then in homes with standard windows and blinds. The study’s participants wore sleep-tracking devices and completed surveys on their health and well-being.

After one week, melatonin production in the body was delayed by 15 minutes when participants used traditional blinds, researchers found. That caused them to fall asleep 22 minutes later and sleep 16 minutes less each night.

On the other hand, when in homes with smart windows, participants showed an 11% reduction in anxiety levels and a 9% decrease in stress levels compared with the week when they used the traditional windows.

“When it comes to choosing a place to live, access to daylight and quality views are key features for prospective tenants,” Piers MacNaughton, vice president of health strategy at View Inc. “This study shows that daylight and views are not just desirable amenities but also have fundamental impacts on our health and even our hormones.”