BEEP BEEP BEEP BEEP BEEP BEEP BEEP You HEAR THAT?
ITS THE WORST.
WAKE UP.
And yet, some people just don't, do they?
I had a roommate in college who was SUCH a heavy sleeper.
He would set his alarm on the loudest volume possible, and when it went off I would JOLT
awake, but he was unphased.
I didn't think I was a light sleeper, but I guess I was?
I would snooze his alarm, but after a semester of this, I definitely harbored some hatred
for this horrible morning ritual.
Turns out, it wasn't really his fault, his brain was just so busy!
Whether you're a heavy or light sleeper has to do with brain activity during the second
phase of sleep.
When the brain falls asleep, it rolls through a number of stages numbered one through four.
One is when you're brain is starting sleep, two is when bursts of activity called sleep
spindles begin, three is delta or slow wave sleep, and four is the well-known REM sleep.
This cycle repeats throughout the night -- with people experiencing different levels of wakefulness
at different times.
Sleep spindles aren't widely understood, but they emanate from the thalamus, a region in
the middle of the brain between the cerebral cortex and midbrain.
The thalamus regulates consciousness, and alertness -- which makes sense.
Sleep spindles have been connected to memory consolidation and learning, brain development
and plasticity, and even diseases like Parkinson's, Alzheimer's, and schizophrenia.
Sleep scientists think the sleep spindles in phase two and three are the key to heavy
versus light sleep.
Spindles don't happen much during REM sleep.
By playing sounds for sleepers at increasing loudness throughout the night, they discovered
sleepers with higher rates of sleep spindles were better at sleeping through the noises!
This is interesting because logically, we might assume the brains of heavy sleepers
are somehow LESS active, but in fact they're MORE active.
You're not "dead to the world" as my mom used to say, but more like, "sawing logs," cerebrally
speaking.
Their paper, published in Current Biology in 2010, says the thalamus' sleep spindles
was sort of... drowning out external stimuli from reaching the cortex causing people to
appear to be heavier sleepers!
Studies of sleep spindles have found women produce more than men, with men averaging
three to six per minute and women ranging from three to more than a dozen.
There IS a mild association -- in women -- between number of spindles and learning potential
(or IQ), but it's pretty weak.
And studies of sleep spindles and biphasic sleeping -- the scientific name for nap time
-- found naps help the memory of preschoolers.
OKAY FINE.
I just want nap time, you guys.
As we get older, the number of spindles dwindle, and we become lighter sleepers.
I'm thinking this may also explain why teenagers can sleep through ANYTHING, but these days,
no way.
What do you think?
Are you a light sleeper or heavy sleeper?