Melatonin, also widely termed as N-acetyl-5 methoxy tryptamine, acts the natural pacemaker for the human body. This hormone is produced in the pineal gland, which is situated in the centre of the brain.
The release of this hormone follows a precise rhythm. Night-time melatonin circulation levels are ten times of that during the daytime.
Not only that, melatonin circulation varies according to seasons as well. During autumn and winter, this hormone is secreted in large amounts, while the secretion reduces during spring and summer. One reason why melatonin secretion varies seasonally is attributed to the changing lengths of days and nights. Autumn and winter have longer nights than spring and summer. Therefore, the amounts of secretion of the hormone vary accordingly.
In other words, the secretion of the hormone depends a lot on the levels of light in one’s surroundings. The Suprachiasmatic Nuclei (SCN) in the brain centre drive the production sync. It is a reduction of light levels during the evening that tells pineal glands to perform their function of melatonin secretion.
Therefore, it is always advisable to keep light levels lowered during the night. Any fluctuation in these levels might lead to a disruption in the biological clock. Such disruption, in turn, ends up affecting regular human sleep schedule.