White light may help cancer survivors sleep better: Study

Cancer survivors often suffer from chronic fatigue, and when they do, a new study suggests that waking up to bright white light may help them sleep better. For the month- long study, researchers had 44 cancer survivors sit very close to a light box early every morning for 30 minutes. The patients were randomly assigned to therapy with either bright white light or dim red light. More than half of the participants suffered from what’s known as poor sleep efficiency, a measure of how much time in bed people spend asleep. After a month of treatment, however, 86 percent of the people exposed to bright white light had normal sleep efficiency, while 79 percent of the people exposed to dim bright light still had poor sleep efficiency. It’s possible that the bright white light helps cancer survivors reset their internal clocks, or circadian rhythms, so that their body can more easily rest at night and wake during the day, said study leader Lisa Wu of the Northwestern University Feinberg School of Medicine in Chicago and the Icahn School of Medicine at Mount Sinai in New York City. “Cancer survivors and even other individuals who spend most of their days indoors may not receive enough bright light to keep their biological rhythms synchronized,” Wu said by email. “Given that light exposure from being outside is generally much brighter than light received indoors, the addition of artificial bright light each morning helps survivors reduce fatigue and improve their sleep quality by strengthening their circadian rhythms.”