“When we are asleep, the brain is not resting at all.”
Is there some truth in a phrase – “Let’s sleep on it”? Where does it come from?
Dmitri Ivanovich Mendeleev, a brilliant scientist who systematized the entire science of chemistry and his Periodic Table of the Elements – a way of organizing every atom that had so far been discovered as well as allowed room for all of the elements yet to be found and in addition, he was even able to predict some of their properties. As the story goes, the idea of atom organization came to him one evening while playing solitaire picturing the nature of the universe when he fell asleep. When he woke up, he promptly created his famous table – interestingly – he organized the atoms in repeating groups of seven, just the way you play solitaire.
Why do we spend a one-third of our time sleeping? What is the brain doing while we sleep? According to John Medina in his Brain Rules, our brain is super active while we sleep, he writes:
“If you ever get a chance to listen in on someone’s brain while its owner is slumbering, you’ll have to get over your disbelief. The brain does not appear to be asleep at all. Rather, it is almost unbelievably active during “rest,” with legions of neurons crackling electrical commands to one another in constantly shifting, extremely active patterns.”
In another experiment, scientists measured brain’s activity of the rat as it is learning to navigate the maze. Wires were put into rat’s brain (electrodes placed near individual neurons) and attached to a recording device allowed to hear up to 500 neurons at once as they processed information. In this experiment, as the rat just learned how to navigate via the maze, it decided to take a nap. When the rat went to sleep, its brain begun to replay the maze-pattern sequence. Its brain repeated what it learned that day. The sequence was replayed thousands of times and much faster than during the day. When the rat was woken up during this stage, called slow-wave sleep, something equally extraordinary was observed, Medina writes:
“The rat has trouble remembering the maze the next day. Quite literally, the rat seems to be consolidating the day’s learning the night after that learning occurred, and an interruption of that sleep distrust the learning cycle.”
Is this true for humans? John Medina seems to believe so:
“Not only do we do such processing, but we do it in a more complex fashion. Like the rat, humans appear to replay certain experiences at night, during the slow-wave phase. Unlike the rat, more emotionally charged memories appear to replay at a different stage in the sleep cycle.”
There is a strong correlation of sleep to learning and brain performance, Medina writes:
“A healthy night’s sleep can indeed boost learning significantly. Sleep scientists debate how we should define learning, and what exactly is improvement.”
According to another set of studies, where students were given a series of math problems, they were able to come up with shortcuts to solve these problems if they were allowed to sleep on it, according to Medina:
“If you let 12 hours pass after the initial training and ask the students to do more problems, about 20 percent will have discovered the shortcut. But, if in that 12 hours you also allow eight or so hours of regular sleep, that figure triples to about 60 percent. No matter how many time the experiment is run, the sleep group consistently outperforms the non-sleep group about three to one.”
Research further shows that –
“The type of learning that appears to be most sensitive to sleep improvement is that which involves learning a procedure.”
Sleep loss takes a toll on the body, too, some of which do not seem to be, at first glance, associated with sleep. Not enough sleep affects, not just learning as explained above, but also:
“[…] sleep loss cripples thinking in just every way you can measure thinking. Sleep loss hurts attention, executive function, working memory, mood, quantitative skills, logical reasoning ability, general math knowledge.”
Researchers early on believed that the reason we sleep is so we can rest; that doesn’t seem to be the truth:
“In fact, the only time you can observe a real resting period for the brain – where the amount of energy consumed is less than during a similar awake period – is during the phase called non-REM sleep. But that take up only 20 percent of the total sleep cycle.”
So what about the time when we do feel tired and sleep actually helps? Medina explains:
“We’ll call it the nap zone, a period of time in the mid-afternoon when we experience transient sleepiness. It can be nearly impossible to get anything done during this time, and if you attempt to push through, which is what most of us do, you can spend much of afternoon fighting a gnawing tiredness. It’s a fight because the brain really wants to take a nap and doesn’t care what its owner is doing.”
Here is a fun fact: Lyndon Baines Johnson, 36th president of the united States and leader of the free world, routinely closed the door to his office in the mid-afternoon and put on his pajamas. He then proceeded to take a 30-minute nap. Rising refreshed, he would then resume his role as commander in chief.
An absolutely insightful read; complement it with Brain Rules, How Exercise Boosts Brain Power or about fixed and growth mind set, reach for The New Psychology of Success.