Tag Archives: cortisol

Fiat lux

Humans have a peculiar relationship with light: differences in brightness, wavelength, and even circadian timing all have biologically meaningful effects.

The right combination of timed light exposure and hot Blue Blockers is probably not only the solution to jet lag, but also to a whole host of other health problems.  Maybe you can’t completely escape the bane of the modern condition, but there are some tools, widely available, accessible, and even free in some cases (eg, sun), that may be of benefit.  

The frequency of light impacts circadian rhythms. 

Wright showed this in 2004.  The subjects wore special glasses with LEDs that emitted light of varying frequency for 2 hours, from 6 to 8 in the morning (65 uW/cm2).  Salivary melatonin measurements commenced at 7 pm.  As seen in the figure below, blue but not red light induced a significant phase advance in melatonin onset:

AM blue light phase advance

And for the whole group:all colors

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