What is the Origin of ALAN?

The term's origin is descriptive, combining the concepts of artificial light and the time of exposure (at night). Its clinical relevance emerged from chronobiology and sleep research, which demonstrated the profound evolutionary dependence of human physiology on the natural light-dark cycle. The widespread adoption of energy-efficient, blue-light-emitting digital screens and indoor lighting systems catalyzed the recognition of ALAN as a distinct public health and wellness concern.

What is the Mechanism of ALAN?

Exposure to ALAN, especially blue wavelengths, suppresses the nocturnal secretion of melatonin by signaling to the suprachiasmatic nucleus (SCN) via the retinohypothalamic tract. Melatonin, a critical hormone, regulates sleep-wake cycles and possesses potent antioxidant properties. This suppression desynchronizes the central circadian clock, leading to phase shifts in hormone release, impaired glucose metabolism, and reduced quality of restorative sleep. Mitigating ALAN exposure is a foundational step in optimizing hormonal balance.

ALAN ∞ Area

ALAN

Meaning

ALAN is the acronym for Artificial Light At Night, representing environmental exposure to non-natural light sources, particularly blue-spectrum light, during the physiological dark phase. This pervasive modern phenomenon is a significant disruptor of the human body’s endogenous timing system, the circadian rhythm. Clinically, excessive ALAN exposure is recognized as a modifiable factor contributing to hormonal dysregulation and metabolic health decline.