Modern life is all about innovating our way out of our inabilities.
And (buzzkill alert) were not meant to be awake when the sun dont shine.
Of all that we can now do, the latter may be the most universal.
If weve mastered anything, its light.
This post originally appeared onVan Winkles.
Trouble is, evolution has programmed the human body to equate light with wakefulness.
Our eyes treat blue-heavy lightlike the soft glow of an iPad like the midday sun.
Heres how to do just that.
As species wandered onto land, the reflectance of the sky perpetuated lifes dependence on blue light for cycle-setting.
(Maybe if humans had evolved on Mars, wed have developed a similar response to red light?)
That evolution has created a complex conduit that translates light into cues that set our daily circadian rhythm.
In turn, signals relay to the pineal gland and suppress production of the sleep-inducing hormone melatonin.
But, despite these adaptations, the human body remains slightly out of sync with Earths 24-hour cycle.
Daylight is the key to keeping rhythms in check.
During sleep, our melatonin levels peak as our core body temperature bottoms out.
This warmer light wont trigger melanopsin, which allows our bodies to produce melatonin and ease into sleep.
As we age, for instance, the way our eyes deal with light changes.
This heightened sensitivity is all-but erased by the time we reach our 20s.
Our location on the globe can also play a key role.
People visiting those areas or traveling across time zones, however will have a tougher time.
Jet lag sufferers know the cranky, groggy, out-of-it feeling all too well.
Such seasonal and geographic disruptions make electric lights something of a Catch-22.
Sleeplessness and late-night partying, onceblamable only on full moons, can now be a daily occurrence.
Maybe lighting is actually an enabler, because whats its doing is its allowing you to disrupt your sleep?
Its a fair point.
Photoreceptors containing melanopsin (remember that handy protein?)
At the same time, the melanopic response requires bright light as much as it does blue light.
At night, the opposites are true.
Now a bit of good news: According to Figueiro, pitch black is not a necessity.
A bit of streetlight or a nightlight in the hallway shouldnt throw you off.
The circadian system is blind to that light.
At the end of the day, experts agree that we need to accept our bodies response to light.
Its not something we can ignore or innovate our way around.
Image bykiberstalker(Shutterstock).
