Hospitals and nursing homes are turning up the lights in some patients’ rooms, amid new research on how light affects mood, energy and sleep, reports The Wall Street Journal.

Some hospitals and nursing homes are seeing the light—and rethinking the dim glow that illuminates most patients’ rooms.

Once an afterthought, lighting is getting attention as researchers see how it affects a person’s mood, energy and sleep. A clinical trial at Mount Sinai Health System in New York City is testing whether bright light in cancer patients’ rooms in the morning can make them feel less tired and depressed and help them sleep through the night.

Phillip Christian Smith, a 48-year-old actor and playwright, took part in the Sinai trial when he was hospitalized in September for multiple myeloma, a cancer of the blood.