Melatonin is a natural hormone which is made by the pineal gland of the body. This is a pea-sized gland which is situated at the top of the center of the brain. At daytime, the pineal gland is inactive. As the sun goes down and darkness emerges, the pineal becomes activated and will begin to produce melatonin actively and then released into the blood. More often than not, this takes place at approximately 9 p.m. which will result to the sharp increase of melatonin levels in the blood. In turn, you will feel less alert which makes sleep all the more inviting. Melatonin levels in the blood could remain elevated for practically 12 hours which is all through the night up and before the light of the new day. They would usually fall back to low levels at daytime at 9 a.m. Levels of melatonin during the day are hardly noticeable.
Aside from making adjustments with the timing of the clock, bright light seem to have another effect. This will inhibit the release of melatonin directly. It is for this reason that melatonin is sometimes referred to as the Dracula of hormones because this only appears in the dark. Although the pineal gland is switched on by the clock, this will not be able to produce melatonin unless the person is in an environment that is dimly lit. Besides the sunlight, artificial indoor lighting can provide sufficient brightness in order to prevent the release of melatonin.
The amount of melatonin which is released at night can vary among people yet this can be related to age. Average children are capable of secreting more melatonin than the adults and secretion decreases more with age. But research has shown that older individuals suffering from sleep problems will not always have reduced melatonin levels when compared to individuals who experience normal sleep. The pattern of waking at daytime when there is light and sleeping during nighttime when darkness occurs is considered to be a natural part of human life. It is only lately that scientists have started to understand the alternate cycles of sleep and waking and how this is associated with daylight and darkness.