Melatonin, a natural hormone in the body that regulates sleeping and waking energy, helped those with Alzheimer’s disease (AD) sleep less during the day and have more energy.
Researchers explained that those with AD, particularly those in nursing homes, often do not get enough natural daylight, which disrupts nighttime sleep and increases daytime sleepiness. Fifty nursing home participants with AD, average age 86, took one hour of light therapy with or without 5 mg of melatonin for five days a week or had normal indoor light without melatonin.
For the light therapy, scientists used natural sunlight when it was bright outside and added artificial sunlight lamps when skies were overcast. After 10 weeks, those who had the light therapy plus melatonin were less sleepy during the day, had more daytime energy and had a better balance in the alternating rhythm of resting and waking energy, called circadian rhythm, the biological clock of the body.
Doctors explained that restoring the circadian rhythm helps those with AD participate in more daytime activities and social situations, which can reduce some of the effects of the disease. The scientists are not sure if melatonin alone or combined with daylight created the improvement and suggest more study.
Reference: Journal of the American Geriatrics Society; 2008, Vol. 56, No. 2, 239-46.