Many elderly people suffer from insomnia. Scientific studies have shown that levels of melatonin, a hormone believed to regulate sleep, decrease as people age. Now a recent study suggests that lack of exposure to light may contribute to or even cause this drop in melatonin levels and the resulting sleep troubles.

Dr. Kauo Mishima of Akita University School of Medicine in Akita City, Japan, compared the sleeping patterns and melatonin levels of 10 nursing home residents with insomnia, 10 healthy residents at the same home, and 10 healthy college students. The insomniacs had the poorest sleep patterns and the lowest melatonin levels.

Then the researchers exposed the insomniacs to 4 hours of bright artificial light around midday for 4 weeks. By the end of that period, the elderly patients' melatonin production had reached levels similar to those in the college students. Their sleep quality also improved.