Predicting melatonin suppression by light in humans: Unifying photoreceptor‐based equivalent daylight illuminances, spectral composition, timing and duration of light exposure

Abstract

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Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults

“…The rationale for basing these recommendations upon melanopic EDI is, in the first instance, provided by a comprehensive analysis of data aggregated from controlled laboratory studies (performed in healthy adults aged 18 to 55) that have evaluated the 2 best understood neuroendocrine and circadian light responses in humans: acute suppression of nocturnal pineal melatonin production and circadian phase resetting by evening or nighttime light exposure [ 36 – 39 ]. Those data indicate that, for a wide range of monochromatic, narrowband and broadband light sources and exposure durations, such ocular light responses are better predicted by melanopic irradiance than by photopic illuminance or other existing metrics.…”

“…The recent meta-analysis discussed above [ 2 ], which could not reach definitive conclusions regarding spectral sensitivity of alerting responses, did not assess the extent to which the magnitude of alerting responses were predictable based on melanopic EDI. Nonetheless, the most informative studies included in that analysis [ 69 , 90 – 94 ] and other relevant studies and meta-analyses [ 36 , 38 , 39 , 69 , 95 ] indicate that alerting effects produced by light of varying spectral composition are certainly better predicted by melanopic irradiance than other available metrics. Moreover, recent studies provide evidence that selectively increasing melanopic irradiance, in the absence of changes in either illuminance or colour, can promote self-reported alertness during both day [ 43 ] and evening [ 40 ].…”

“…Importantly, as originally envisaged [ 28 ], adoption of the new measurement approach has facilitated a number of large-scale retrospective evaluations of historical data [ 35 – 39 ] and informed new hypothesis-driven investigations [ 40 – 43 ] on the photoreceptive physiology for circadian, neuroendocrine, and neurobehavioural responses in humans. In total, the evidence from such studies [ 35 – 43 ] supports the view that, under most practically relevant situations (extended exposures to polychromatic light in the absence of pharmacological pupil dilation), light sensitivity of human physiological responses can be reliably approximated by the α-opic irradiance for melanopsin or the corresponding EDI (melanopic EDI).…”

Melatonin suppression does not automatically alter sleepiness, vigilance, sensory processing, or sleep

“…This notion has received support from findings that melatonin suppression is particularly strong when short wavelength proportions are high (Cajochen et al, 2005;Chellappa et al, 2011;Revell et al, 2006) and that 'blue'-blocking glasses can mitigate neuroendocrine and alerting responses (van der Lely et al, 2015). A recent meta-analysis even confirmed that the relationship between melanopic illuminance and the delay in sleep onset follows a dose-response relationship (Giménez et al, 2022). Further mechanistic evidence comes from studies using metameric conditions designed to affect the melanopic system only, as in the present study (Allen et al, 2018;Souman et al, 2018a).…”

Optimizing exterior lighting illuminance and spectrum for human, environmental, and economic factors.

“…Functionality [19][20][21][22][23] Perception [24] Human Health [20,[25][26][27] Night Sky [29][30][31] Animals [25,26] Plants [28] Energy [32][33][34][35][36][37] Cost [32-…”