New findings suggest turning down indoor lighting at night, and keeping the room dark during sleep to increase melatonin production could reduce insomnia, keep blood pressure in check and lower the chances of developing diabetes. Melatonin has been studied for its role in treating cancer, poor sleep and hypertension.
Source: J. Clin. Endocrinol. Metab.doi:doi:10.1210/jc.2010-2098