The Secret Life of Sleep

Kat Duff Also available in audiobook: Download our app for free listening.

Can you remember the last time you had a good night of sleep? Sleeping well is a vital issue for any human being. Our memory and our motor skills begin to fail when we don't get enough sleep. Everyone knows someone who doesn't sleep much and yet says they're highly productive. This book wants to demystify this association and prove that sleep is very important to your productivity and success! Understand how having a satisfactory and adequate sleep will help you work, think and perform your tasks with much more quality and efficiency.

Our organism chemically regulates sleep

Recent advances in neuroscience indicate that sleep replenishes your body and also invigorates your mind, improves your cognitive functions, and leaves you less vulnerable to depression and obesity.

Also, scientists have discovered that humans possess a sleep switch. In 2001, a sleep researcher named Clifford B. Saper of Harvard University identified a neurons cluster in the hypothalamus - the region of the brain that controls metabolic processes and activities such as hunger and body temperature - called a switch of sleep '.

Our bodies have a mechanism to chemically regulate sleep. Its functions are independent of day or night, and maintain the internal balance to make us sleep more or less, thanks to a substance called adenosine triphosphate (the famous ATP). ATP runs out through the day, making us tired until we fall asleep. Then, during our sleep, other substances accumulate gradually until they reach a peak, and then we wake up.

The state when these neurons are disconnecting, and we begin to sleep is called hypnagogic, and its parallel transition state when we wake up is called hypnopompic.

During these parallel states, we can feel inspired. We can also relive daily events, see geometric patterns in our vision, feel we are falling or floating, or think we are expanding or contracting in size.

In these moments we can connect with the world and have the chance to access other dimensions or realities. Salvador Dalí used these techniques in his paintings, which were inspired by his dreams.

Thomas Edison also used these parallel states to solve problems. He did this by snoozing while holding steel balls in his hands. As he fell asleep, his hands relaxed, and the balls fell and woke him up, and with luck, he would have a solution to his problems!

Sleep is influenced by our culture

Everyone sleeps at one time or another. Studies have shown that even those who have chronic insomnia experience micro-sleeps, small amounts of sleep lasting from one to 30 seconds. We all sleep in different ways and culture is a critical factor in determining how you do it.

In the Western post-industrial world, individuals usually have a sleep routine, and they do this in separate rooms for a set time. These habits are all set to accommodate the demands of work and choices, and fit into a time pattern.

But other cultures may have more fluid sleep patterns, sleeping for short periods, and using different practices.

In medieval Europe for example, sleep was often divided into two parts, with one-hour sleep sessions between sexual activities or meals. Currently, those in warmer climates like Spain, prefer an afternoon siesta to supplement the night's sleep.

In regions such as Asia, Africa, America, Southern Europe and parts of Scandinavia, its standard to practice a technique called 'co-sleeping,' in which children sleep very close to their relatives' arms.

Although this practice is considered strange for those who don't live in these places, some believe that co-sleeping has positive effects on adult behavior. Mothers in Mayan culture claim that their children feel connected to others, and this improves their ability to learn from them.

For the Anglo-Saxons, the 'co-sleeping' technique ceased in the middle of the 1800's because Americans learned children should sleep in separate rooms to develop independence. However, letting a baby cry alone can make him, or her, feel oversensitive, and this may disrupt the development of resilience.

Also, studies in different cultures have found that children who share a room with their parents between birth and five years of age are likely to be happier, more cooperative, confident and independent than children who sleep alone.

Two different sleep states

Scientifically speaking, sleeping is a floating state that has two main forms: rapid eye movement (REM) and slow waves (SW). These shapes alternate between five and six times a night, on average every 90 minutes.

Both states are described by two characteristics: attenuated responses to external stimuli and the ability to wake up. These characteristics differentiate these states from others as the comma.

REM sleep gets its name from rapid eye movement. This is the most active state of sleep, and it warms our brain, requiring other states to calm it down. At REM, our dreams are vivid and abundant.

Neuroscientists Antti Revonsuo and Patrick McNamara have discovered that we also use REM to learn. Revonsuo believes that REM dreams, such as dreaming that you are fleeing from an earthquake, function as a method to rehearse and refine survival strategies. McNamara sees REM dreams as versions of past events that can be interpreted as a learning process.

On the other hand, SWS, slow-wave sleep is a deep sleep, which represents slow, high amplitude, and synchronized brain waves. And it's much harder to wake up in this state. SWS is our most restorative form of sleep, and it also burns fat, which explains why not getting enough sleep can lead to obesity. It's probably our most needed form of sleep, and during SWS, our dreams are fragmented and vague.

As for those over the age of 50, the amount of SW sleep begins to decrease with time. In fact, about a quarter of the population over 50 no longer have SW sleep. This may be a characteristic factor of aging, as well as decreased muscle tone and physical strength, increased body fat, memory loss, and decreased immunity.

Sleep deprivation may have serious consequences for our health

Unfortunately, having trouble sleeping at night is common. According to a 2008 US National Science Foundation survey, 35% of Americans said they wake up in the middle of the night three or more times a week. To get a sense of the drama, most Americans would rather have good nights of sleep than sex.

Sleep deprivation leaves us tired and is also bad for our brain and body. In a state of sleep deprivation, performances suffer, immunity is compromised, and stress hormones increase. Also, sleep deprivation compromises the ability to learn, assess situations and respond to stimuli.

Even more disturbing, studies have found that a week sleeping only four or five hours a night may have cognitive implications similar to people with 1% blood alcohol levels.

Try to divide your sleep into two parts. In 1990, psychiatrist Thomas A. Wehr conducted an experiment in which eight volunteers spent 14 hours in the dark every night for a month. Then they began to gradually get nine hours of sleep, scattered in 12 hours, waking up for a few hours between periods.

When the study was over, the participants missed this peaceful time. Participants also experienced high levels of calm, and satisfactory levels of the hormones melatonin and prolactin, which also support nerve cells growth but those levels fell after the experiment.

Our attitudes can also help relieve insomnia. Modern societies see money, success, and accomplishments as more valuable than having a good sleep and rest. A change in perspective can lead to a much healthier sleep cycle.

Also, our society's attitude, artificial light also affects us. Our bodies are connected with the sunrise to regulate our sleep cycles. Melatonin is only produced at night and is crucial to induce sleep. Looking at the computer screen until 2 in the morning interrupts this natural process.

When we don't, know if we are asleep or awake

Everyone has already woken up and didn't understand if the dream was real or the result of imagination. The truth is, once you wake up, it is difficult to distinguish dreams from reality.

Each culture has its way of interpreting this division between dream and reality. African traditions, for example, see sleep as a way of communicating with the dead and receiving counsel.

We all dream, and some of us experience hallucinations, syncope, or loss of consciousness. But distinguishing between these states and our awake state isn't always clear. Sleeping and waking are interconnected, these states are complete, and so it is sometimes difficult to isolate one from the other. Our daily worries sometimes invade our dreams, and our dreams sometimes linger into the morning.

In 2008, psychologist James M. Krueger of the University of Wisconsin discovered that sleep can occur in some parts of the brain while other parts are still awake. With that, a friend of the author compared this process to popping popcorn: you don't know what popcorn will pop next, but eventually, all will burst, and in then, put you into sleep mode.

Then, when small, independent groups of neurons get tired, they release more ATP and enter a sleep state while other neurons remain awake. But when a group of neurons goes into sleep, neighboring groups follow. This suggests that the transition between the waking or sleeping mode may take longer and be more complex than previously thought.

Sleep improves memory and reason

Many of us, even unintentionally, wake up in the morning with a sense of laziness, since we are being forced to get up. But sleeping long enough is essential to our cognitive, physical, and emotional well-being.

SW sleep preserves our memories by recapturing the information we learn during the day, while REM sleep incorporates these memories into what we already know.

The result is what  researchers call 'memory consolidation.' This happens when the neural connections we rarely use become weaker, and newer memories are strengthened as our brain remembers them. As we sleep, short-term memories become long-term.

This process was discovered in the 1990s by neuroscientist Matthew Walker in his experiments on rats. He found that rats "practiced" the brain in a maze, 20 times faster when they slept than when they were awake.

These same mice were also better at running through the labyrinths after they had slept. In that sense, we function like rats; we remember things better after sleeping and often wake up with more ability to solve problems. Therefore, researchers advise students to take naps to help with their studies.

Sleeping also helps us better deal with emotions, a benefit demonstrated by dream specialist Rosalind Cartwright. For five months, Cartwright cataloged the dreams of 20 newly divorced men and women, and half of them had symptoms of clinical depression.

Those who remembered their dreams more often experienced more complex and longer dreams that were often integrated with their recent emotional experiences. This group has recovered better than those with shorter dreams. As Cartwright explained, dreams were like rehearsals for patient recovery.

Also, our dreams can help us with emotional traumas, showing us multiple perspectives, and helping us understand and process experiences in more efficient ways.

We all dream, but not all remember

Dreaming is an innate characteristic of human beings; researchers found that we dream about four or six times a night. So we shouldn't question whether we dream or not, but why some remember and others don't.

Remembering dreams has a connection with one's personality, how one wakes up, attitudes toward dreaming, sleep length, and dreams intensity. Studies have shown that we forget about half of our dreams in the first five minutes after waking, and we forget about 90% of dreams only 10 minutes later. Our memory gets poorer if we wake up with an alarm or if we don't get enough sleep.

So how can we remember our dreams? Experts suggest that with a good night of sleep and with thoughts that you want to remember them in the morning. When you wake up, you should lie down and recognize what you feel, watching an image or sensation, and writing everything as soon as possible.

Although our dreams are different, most of us make a distinction between everyday dreams and extraordinary dreams. Carl Jung, the founder of analytical psychology, calls them big dreams and small dreams.

Big dreams are unforgettable and result in considerable life changes or experiences; they not only contain memories but create new experiences beyond our current knowledge. The most common ones involve a visit from someone who has passed away. Those dreams are profound, as psychiatrist William Dements dreamed of suffering from incurable lung cancer, which led him to quit smoking the next day. Abraham Lincoln dreamed he would be murdered a few days before he was killed.

Small dreams are the opposite and are characterized by more mundane concerns.

We need time to fully wake up

People who wake up recharged are rare, most of us wake up with some difficulty. And this happens thanks to social jet lag and sleep's inertia.

Social jet lag describes the disagreement between our biological internal rhythms and our sleep schedules, which are usually determined by work or school.

Our circadian clocks are responsible for most of our daily fluctuations, including blood pressure, body temperature, immune system, hormones, appetite, thirst, and our sleep cycles.

These changes affect the length of sleep we need, determine if we are nocturnal owls or diurnal animals, and affect how we wake up. However, thanks to our daily racing routines, and the constant use of electric light, we now sleep and work at times that are not always compatible with our natural rhythms.

Chronobiologist Till Roenneberg, who created the term social jet lag, estimates about 40% of Central Europeans are constantly missing two or more hours of sleep. In the long run, this can seriously compromise human health, leading to chronic fatigue, digestive problems, and weight gain.

Also, in 2007, the World Health Organization stated that disruptions to circadian rhythms through changes in work might even be carcinogenic.

In addition to social jet lag, many people suffer from the sleep's inertia. This refers to the difficulty in getting out of bed, and this is based on Newton's first law, which states that a resting body tends to remain at rest. Our brains don't start fast like the lamps, as soon as we wake up; instead, some regions of the brain activate faster than others.

Research shows that memory, manual dexterity, and complex decision making are hampered by the sleep inertia. And one of the researchers says this condition can be as bad as the legal limits of blood alcohol.

Final Notes

Lack of sleep is a major health problem and a major scientific mystery. Nowadays, our hurried routines make us ignore the importance of a good night of sleep, but the truth is that many modern diseases could be prevented or at least mitigated. Don't neglect your sleep, sleep well and ensure the proper functioning of your brain!

12min Tip

Want to learn a little more about the importance of sleep? Read 'The sleep revolution'!

Sign up and read for free!

By signing up, you will get a free 3-day Trial to enjoy everything that 12min has to offer.

or via form: