If you follow me on Instagram, you probably know I went to the North Pole recently, and
this time of year the sun never sets.
It was crazy.
Why is it so hard to sleep when it's light out?!
Hey light sleepers, Trace here.
This is DNews.
Everything sleeps (or has some kind of active and inactive cycle), but not everything sleeps
at night, like we do.
Regular DNews watchers will know about the circadian rhythm, the pattern of sleep and
wakefulness connected to the amount of light entering the eye.
When we perceive daylight, our brains lessen the release of melatonin, making us more wakeful,
and at night?
More melatonin, more sleepy.
But, it’s not just about sleepiness.
Even self-proclaimed night owls need darkness to sleep.
We evolved to sleep in the dark, and we know this because when it's dark our hormone levels
fluctuate causing widespread changes in our physiology.
Melatonin lowers blood pressure, sugar levels, and body temperature.
Leptin makes us less hungry.
Both of these prep us for rest.
When we're sleeping, the levels of cortisol, a stress hormone, drop, and our immune function
improves.
Even though this explains why we sleep at night, it doesn't tell us why we evolved this
way.
Sleeping at night is actually kinda weird.
Only 20 percent of mammals sleep at night.
Most mammals are nocturnal, spending their days tucked away for sleepytime.
A study of fossils from the last 100 million years found nocturnal species evolved even
before mammals appeared.
Primates don't have a specific pattern of day-night cycling, in fact, a study in the
American Journal of Physical Anthropology looked at fossils of primates and found species
can be either diurnal (day active) or nocturnal (night active).
But because we sleep at night, modern humans probably evolved from a diurnal group of ancient
primates.
And this is supported by scientists who study pre-industrial societies.
They've found humans went to sleep just after sunset for a while, woke up, were active in
the middle of the night (in the dark), then slept again -- that's called second sleep.
That's our natural order, sleeping twice, in the DARK.
But now, even a little light can mess up your sleep schedule.
Because our brain is watching, alllllways watching and gets confused when any light
is present… because it didn't evolve to have light at night.
Even when your eyes are closed your brain sees light through your eyelids, and lowers
melatonin release.
You're affected by glowing electronics, digital clocks, and lights from other rooms or the
street that shine onto you.
A study with rats found they slept in different positions and had different sleep behaviors
when exposed only to twilight sleep, and a study with hamsters found signs of depression
when they slept with light at the equivalent of a glowing tv screen in their room.
Studies have correlated excess light at night with breast cancer, and darkness at night
with better performance of a breast cancer drug, and even connected lessened tumor growth
with more sleep.
Not to mention all the normal immune, obesity, depressive and other health effects associated
with sleep.
So, while we don't know exactly why we evolved to sleep in the dark, we know our eyes and
brains have adapted to work better during daytime and not at night…
thus, we should sleep in a dark room, regardless of the actual time of day.
And this is supported by the National Sleep Foundation, so... maybe… *yawn* I should
just… have a nap.
Gimmie that pillow.
And if you are going to have a nap, sleep soundly because AT&T Digital Life smart home
security helps keep you connected to you home, so there are no more what ifs.
*yawn again* Why is it that Yawning makes you want to yawn?
Why do we even YAWN!?
This ooooooooold video opens wide and checks on this weird universal behavior.
Do you sleep in PURE DARKNESS?
Or are you more of a meh, I'll sleep anywhere, kind of person?