Melatonin is a natural hormone produced in the brain by the pineal gland. As our bodies age, the level of melatonin production goes down. The secretion of melatonin is also affected by light, more is produced in the darkness and it is inhibited by daylight. The hormone works by causing sleepiness and lowering your body temperature much as natural drowsiness does.
Many researchers believe this is why, as we grow older, we sleep less. It would also explain why people feel sleepier during the winte