Why We Sleep: The New Science of Sleep and Dreams is a survey of modern sleep research by Matthew Walker, Ph.D., a sleep scientist who is a professor of neuroscience and psychology at UC Berkeley, and the Director of its Sleep and Neuroimaging Lab. (Check out the latest price on Amazon HERE!!!).
Sleep is a crucial element of human health. Sleep facilitates memory, creativity, problem-solving and the acquisition of motor skills. It recharges the immune system, modulates blood sugar, clears coronary arteries and wards off disease.
The lack of sleep, on the contrary, has become an epidemic problem which causes devastating results and leads to numerous diseases. Some results of sleep deprivation are high blood sugar levels, cardiovascular strokes, depression, and anxiety.
This book is extensive, based on facts and scientific research, which unveils sleep’s connection to health. According to Dr. Walker, the primary goal and gain from sleep is the ignition of brain function and body health every day
The book has been organized into four main parts, that can be read in a different order without missing the key information and the central point of discussion. (Whatch an animated review of Why We Sleep on Open sourced Workplace - HERE)
Nowadays, most adults around the world are not getting the proper amount of sleep at night.
“Two-thirds of adults throughout all developed nations fail to obtain the recommended eight hours of nightly sleep.” Matthew Walker
· doubles their risk of developing cancer
· disrupts the levels of blood sugar, leading to pre-diabetic
· increases the chance of several heart diseases
· creates the factor for the development of Alzheimer’s disease
· contributes to anxiety, depression, and even suicidal thoughts
· concentrates the hormones in our body that make us feel famished
But on the contrary, sufficient sleep:
· restores the immune system
· refines our metabolic state
· controls the appetite
· improve our abilities to learn, memorize, make choices and decisions
According to Dr. Walker, the two factors that determine the feel of sleep and awake are the melatonin and adenosine respectively.
The first one is a signal from the internal twenty-four-hour clock in the brain; what’s called a circadian rhythm. The twenty-four-hour biological clock in the middle of the brain is called the suprachiasmatic nucleus. It relays repeating signals, noting day and night, to the brain and body using a circulating messenger called melatonin, which the only task is to provide instructions to the brain and body to initiate sleep.
The second comes from a chemical substance in the brain that creates sleep pressure. A chemical called adenosine is developed in the brain, and the longer you’re awake, the more adenosine will accumulate. Increasing adenosine in the brain leads to an increasing desire to sleep.
“You can artificially mute the sleep signal of adenosine by using a chemical that makes you feel more alert and awake: caffeine.” Matthew Walker
Do you know whether you’re routinely getting enough sleep?
- Do you wake up naturally at time of alarm?
- Do you need to read a sentence twice?
- Do you get drowsy a few hours after waking?
- Do you need coffee to feel functional?
What happens whenever we fall asleep?
1. There’s a loss of external awareness.
2. There is a sense of time distortion.
Sleep verification requires recording signals arising from three different regions: brainwave activity, eye movement activity, and muscle activity.
It was discovered that humans’ cycle through different types of sleep every ninety minutes. These sleep stages are non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep.
REM sleep is also called paradoxical sleep: the brain appears awake, yet the body is asleep. The brain activity during this stage is not that different from the activity our brain experiences when we’re awake. During REM sleep, signals from different emotions, feelings, and memories are played out inside the brain.
NREM sleep has stages 1 and 2, going into deeper stages 3 and 4, which are also termed “slow-wave sleep.” Each slow wave of NREM sleep serves as a messenger, carrying packets of information between brain centers. It moves memories from short-term storage to a more permanent, safer, long-term storage location.
The three stages in terms of information processing act very differently.
Sleep is universal. While the author believes that sleep is a unifying feature across the animal kingdom, yet there is remarkable diversity in amount, form, and pattern.
According to the author humans, have something exceptional in terms of nightly sleep. The intensity of the REM sleep and the degree of sociocultural complexity, as well as cognitive intelligence, are all beneficially shaped by the hand of sleep.
REM sleep enables people to make more intelligent decisions and actions as a consequence, and it fuels creativity.
The author addresses that while NREM sleep helps to transfer and save newly learned information into long-term storage regions of the brain, it is REM that takes these fresh memories and “mixes” them with the entire back catalog of your life.
Sleep before birth
Before birth, a human infant inside the womb spends its time suspended in a REM-like sleep state, which is vital for promoting brain maturation. By the end of the second trimester, the majority of the neural dials and switches required to produce NREM and REM sleep are developed. Sleep time decreases at the last trimester.
Because of the fact that the circadian rhythm takes considerable time to develop, infants and young children will constantly experience sleepiness throughout the day and night, which is also marked by numerous awakenings.
The proportion of REM sleep also decreases in early childhood, while NREM sleep increases, even though their total sleep time decreases.
Sleep and adolescence
During this stage, a generic brain becomes more individualized based on the unique experiences of the child. Deep NREM sleep performs final refinement of the brain during adolescence. Sleep appears to be the one that paves the way to mature thinking and reasoning ability.
Sleep in midlife and old age
Sleep does become more disordered the older we get. While REM sleep remains largely stable in midlife, the decline of deep NREM sleep is underway. The strength of our circadian rhythm and the amount of nighttime melatonin released decreases the older we get.
“Passing into your mid- and late forties, age will have stripped you of 60 to 70 % of the deep sleep you were enjoying as a young teenager. By the time you reach seventy years old, you will have lost 80 to 90 percent of your youthful deep sleep.” Matthew Walker
Sleep the night before studying
Sleep restores the brain’s capacity for learning, making room for new memories. This whole process of creating more “storage space” happens in stage 2 NREM sleep and produces short, strong bursts of sleep spindles.
Sleep the night after learning
The second benefit of sleep for memory comes after learning. Sleep protects newly acquired information, affording immunity against forgetting. According to research, the deeper NREM sleep, the more information an individual can remember the next day.
Sleeping to forget
The capacity to forget can also be important as the need for remembering. Sleep helps retain everything you need and nothing that you don’t. It is NREM sleep separating those that should be retained and those that should be removed.
There are many ways in which the lack of sleep can kill a person.
“We are socially, organizationally, economically, physically, behaviorally, nutritionally, linguistically, cognitively, and emotionally dependent upon sleep.” Matthew Walker
Proper sleep is more than just a pillar of good health. The leading 5 main facets of disease and death linked to a lack of sleep as supported by Dr. Walker are:
1. Lack of sleep is associated with the increased risk of developing coronary heart disease. Deep sleep prevents an increase in physiological stress synonymous with increased blood pressure, heart attack, and stroke.
2. There are two hormones that control our appetite: leptin, which signals a sense of feeling full, and ghrelin, which triggers a strong sensation of hunger. Sleeping less decreases concentrations of leptin and increases levels of ghrelin, increasing the chance of gaining weight, becoming overweight, and developing type 2 diabetes.
3. In males, sleep deprivation decreases testosterone, testicle size, sperm count. On the contrary in females, sleep deprivation reduces follicular-releasing hormone, increases abnormal menstrual cycles, and had more issues with infertility.
4. Sleep helps the body fight against infection and sickness. More forms of malignant tumors are being linked to insufficient sleep. Poor sleep quality provides a toxic fertilizer for its rapid and more rampant growth.
5. Chronic sleep loss destroys the very essence of biological life itself: the genetic code and its structure. Thousands of genes within the brain depend upon consistent and sufficient sleep for their stable regulation.
Most vivid dreaming happens during REM sleep, when the visual, motor, memory, and emotional areas of the brain are active.
Freud considered dreams as evocations of repressed desires, and he built a movement around interpreting dreams as such. He believed that dreams came from unconscious wishes that had not been fulfilled.
Do dreams replay events of the day, or do they reflect our emotional concerns?
· Only a small fraction (1-2%) of dreams replay the literal events of the day.
· A greater fraction (~45%) reflect our underlying emotional worries we have while awake.
When the human brain produces REM sleep, it can also produce dreams. Dr. Walker supports that REM-sleep dreaming could act as an overnight therapy by providing the following functions.
Dreaming about the upsetting content itself, is necessary to have this emotional blunting effect. In REM sleep, the brain is allowed to process upsetting memories in a “safe” brain environment without feeling stressed by them.
There are brain regions whose job is to read and decode the value and meaning of emotional signals, especially faces. Sleep deprivation reduces interpretation of the subtleties of facial expressions, causing the sleep deprived person to more likely interpret faces as hostile and aggressive. The outside world becomes a more threatening and crueler place.
As stressed by Dr. Walker REM sleep and the act of dreaming inspires creativity and promotes better problem solving.
Solutions seemed to arrive more effortlessly and instantaneously when the brain has just experienced dream sleep.
REM sleep is capable of creating abstract overarching knowledge and superior concepts out of sets of information. This is why you’re instructed to “sleep on it”.
The dream algorithm was picking important fragments of the prior learning experience, attempting to place those new experiences within the back catalog of pre-existing knowledge.
“As we enter REM sleep and dreaming takes hold, an inspired form of memory mixology begins to occur.” Matthew Walker
Why We Sleep covers a variety of diseases related to abnormal sleep: Somnambulism, Insomnia, Narcolepsy and, Fatal Familial Insomnia. The science of these disorders can further enlighten us about the mysteries of sleeping and dreaming.
There are five key factors that have powerfully contributed to how much and how well we sleep:
1. Constant electric light and LED light - any light is disruptive to the circadian rhythm. Blue light is most problematic, suppressing melatonin at twice the levels of warm light.
2. Regularized temperature - In natural environments, the temperature rises and falls with the day. This is used by the hypothalamus, along with light, to set the circadian rhythm.
3. Caffeine – the most widely used psychoactive stimulation in the world.
4. Alcohol - Alcohol is a sedative, causing what appears to be sleep but is really more like anesthesia. It disrupts sleep by suppressing REM sleep and causing waking throughout the night.
5. Alarms - The industrial era inflicted another damaging blow to our sleep: enforced awakening. The artificially awakening from sleep, expose the heart to repeated shock.
Sleeping pills don’t create natural sleep. They can contribute to the increase of health problems and risks of developing life-threatening diseases. Sleeping pills can also cause rebound insomnia. When individuals stop taking these medications, they often suffer far worse sleep.
On the contrary, according to Dr. Walker research, there are also numerous effective behavioral methods for improving your sleep, especially if you’re suffering from insomnia. The most effective of these is called Cognitive Behavioral Therapy for Insomnia or CBT-I.
It builds on basic sleep hygiene principles, supplemented with methods individualized for the patient, their problems, and their lifestyle. These methods involve:
- keeping the same waking and sleeping time
- reducing caffeine and alcohol intake,
- removing screen technology from the bedroom
- having a cool bedroom
- eating a normal diet
Deep currents of sleep neglect circulate throughout all developed nations. This is why the World Health Organization now labels the lack of societal sleep as a global health epidemic.
“One out of every two adults across all developed countries (approximately 800 million people) will not get the necessary sleep they need this coming week.” Matthew Walker
The effects of sleep deprivation are costly.
Lost productivity per sleep-deprived worker is in the thousands of dollars a year. In Why We Sleep, Matthew Walker argues insufficient sleep costs 2% of GDP.
Encouraging employees, managers, and CEOs to work after a well rest turns them from being ineffective to being productive, honest individuals who inspire, support, and help each other. Sound sleep is clearly sound business.
Another important group of people highly affected by sleep deficiency are teenagers. Early school start times does nothing good when it comes to nurturing the physical and mental health of children and teenagers. According to studies, the longer children sleep, the more intellectually efficient they are.
We all must understand why the problem of deficient sleep seems to persist and grow worse. Dr. Walker proposes a structured model developed for effecting change to happen.
Technology can be used to our advantage. Within a few years, there could be devices that accurately track an individual’s sleep and circadian rhythm. Exposure to your own data can be practiced converting a healthy new habit into a permanent way of life.
Research suggests that sleep holds no place in the education of our children. There aren’t any educational materials or information given about sleep. A simple educational module can also be implemented in schools around the world.
Changing the business culture to a more flexible concerning the life cycle of an employee is wise and considerate. Improving and designing new proper sleep conditions at work productivity, creativity, work enthusiasm, energy, and efficiency are to be flourished.
We need better public campaigns educating the population about sleep. Governments could save hundreds and thousands of lives each year if they mobilized such campaigns.
Human beings have been neglecting one of the basic and most important need in life, which is sleep. Modernity has significantly influenced our way of living.
“This silent sleep loss epidemic is the greatest public health challenge we face in the twenty-first century in developed nations.” Matthew Walker
In this book, Dr. Walker shares the results of the decades of cutting-edge research spent in the field of sleep science. He offers a deeply informative, well-organized and a clearly written book for both patients and professionals.
The author decided to focus more on the aspect of the importance of sleep, and so the readers provided with scientific information are urged to change their sleeping habits.
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