What is the Origin of Melatonin Suppression Thresholds?

This term is a cornerstone of human chronobiology and sleep medicine, developed through controlled laboratory experiments measuring plasma or salivary melatonin levels in response to varying light parameters. The research established a quantitative relationship between light stimulus and endocrine response. This quantification allowed for the creation of clinical guidelines for light hygiene.

What is the Mechanism of Melatonin Suppression Thresholds?

Light signals travel from the retina, via the intrinsically photosensitive retinal ganglion cells containing melanopsin, to the suprachiasmatic nucleus (SCN), the body's master clock. When light intensity exceeds the specific threshold, the SCN transmits an inhibitory signal to the pineal gland, effectively halting the enzymatic conversion of serotonin to melatonin, thus signaling biological daytime and disrupting the preparation for sleep.

Melatonin Suppression Thresholds ∞ Area

Melatonin Suppression Thresholds

Meaning

Melatonin Suppression Thresholds define the minimum intensity and specific wavelength of light exposure required to inhibit the nocturnal secretion of the hormone melatonin by the pineal gland. This is a critical chronobiological metric, as exposure above this threshold during the biological night can acutely disrupt circadian rhythmicity and impair sleep quality. The threshold is typically lowest for blue-wavelength light, demanding careful light management in the evening.