WHY DO HUMANS SLEEP?

To sleep, perchance to dream…. Hamlet

I learned recently that bees do not sleep. Neither do wasps. I add such trivia to the brain folder that has long held similar information regarding sharks. I also find it fascinating that sharks, which do not sleep, must also keep moving. If they were to stop moving, the research indicates, they die. Incredible.

A long time ago, I learned from a notable source that while professionals in the fields of science and medicine can outline many benefits of sleep, in actuality, they cannot explain “why” we sleep. There are theories as to the reasons for sleeping, but they remain only theories, not scientific fact.

Two prominent theories for why we sleep are the “Inactivity Theory” and the “Energy Conservation Theory.” The former, sometimes called the adaptive or evolutionary theory, suggests that sleep at night developed as a survival function by keeping humans out of danger during times of greater vulnerability. The latter theory, posited by studying the life patterns of human “hunters and gathers,” concludes that sleep became a means of reducing an individual’s demand and expenditure of energy during times when it is least efficient to search for food.

Sleep research in the last century has focused on what is called the “restorative theory.” That is, sleep somehow serves as an opportunity to “restore” what is lost in the body while we are awake. There are also “rejuvenating” features of sleep. For example, we have learned that certain neuronal activities, necessary for cognitive function, seem to occur only during sleep.

Even more recent studies focus on the “Brain Plasticity Theory,” indicating that sleep is correlated to changes in the structure and organization of the brain. Research has provided ample evidence that sleep plays a critical role in the brain development of infants and young children. Also, as children grow and enter puberty, there is a significant shift in their circadian rhythm (their “internal clock”). Human circadian rhythm describe the body’s function of making one feel sleepy at regular times every day. In the changing bodies of teens, this rhythm shifts to a couple hours later. Hence, a child’s internal clock may have brought on “feeling sleepy” anywhere between 8 and 10 p.m.

In teens, this “sleep phase delay” is responsible for their not being able to fall asleep until 11 p.m. or later. Since the average teen still requires about 9 and a half hours of sleep per night, simple math indicates that a teen may not be fully rested until 8:00 a.m. or later. It seems a no-brainer that the beginning of the school day for teens needs to be reconsidered. After all, we’ve long known that the “school day schedule” is determined, not by what is most beneficial for students, but by its convenience and suitability for adults.

So. Why do we sleep? We don’t know. Do we need REM sleep? Yes, apparently. REM sleep is the time of greatest brain activity, when the “restorative” neuronal activities occur that contribute to overall cognitive functioning. Do all of us dream? Yes, although we don’t know why. Most people dream about two hours during the night, although many people cannot remember their dreams. And yes, some people dream in color, others can only remember their dreams in black and white (now that’s something worth investigating!). Dreams occur during all the different stages of sleep, although they are most vivid during REM sleep.

vincent-bedroom-in-arles-vincent-van-gogh-538149184.jpg
A POEM ON SLEEP (author: “the tortilla,” theodysseyonline.com)

Submerged in a cocoon of cloth
Mentally withdrawn
Into the twisted endless labyrinth
Living in maybes
Where make believe is reality
Impossibilities are truth
Memories tainted by mixed emotions
Faces blurred to irrelevance
Personalities flourish mingled by my unreal standards
Distilled delusions
The idea of you is distorted gaily
In-n-out
Content with this smokeless high
Induced by my own weariness
Situations run hand-n-hand with creativity
Vivid pictures play
Trapped in unknown dimensions
Without time
Worries choose, melting or magnification
Replayed happenings
Words unspoken to scream
My real life gone
Tonight I leave

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