A journey based on scientific analysis in the mysterious world of sleep and the enormous benefits that sleep brings us, such as increasing our memory or helping us in the prevention of trivial conditions such as colds or less trivial such as cardiovascular diseases. The ideas in this article will serve as a real guide to a healthier lifestyle and healthier habits.
Sleep: the possible consequences of not sleeping 8 hours and its benefits
Two thirds of adults in all developed nations do not enjoy the much recommended 8 hours of sleep per night. If this fact doesn’t surprise you, the consequences will surprise you. In fact, there is a very close link between lack of sleep and the onset of diseases such as cancer, Alzheimer’s, diabetes, obesity, cardiovascular diseases, mental suffering such as depression, anxiety and the propensity to commit suicide. Lack of sleep is also the cause of numerous road accidents every year.
Despite being one of the most important aspects of our life, sleep remains one of the greatest biological mysteries. In recent years research has begun to understand the tremendous benefits that sleep provides both the brain and the body.
Sleep enriches our ability to learn, memorize, make logical decisions, has a beneficial influence on our psychological health by recalibrating our emotional circuits. Dreams create a virtual reality that combines past knowledge with present knowledge favoring creativity.
Sleep restores the harmony of our immune system, recalibrates the blood glucose balance, regulates our appetite. There is no other state that is equally capable of rebalancing our physical and mental health. There is no biological function that does not benefit from a good night’s sleep.
How caffeine affects melatonin and adhesonine, hormone and nucleoside that regulate our sleep-wake cycle
There are two main factors that determine the sleep-wake cycle. The first is a signal from your internal clock located in the center of the brain. This watch creates a 24-hour cycle, a day-night rhythm, the so-called “circadian rhythm” that makes you feel awake or tired at regular times. It is found in the hypothalamus and is called the suprachiasmatic nucleus.
Melatonin : the suprachiasmatic nucleus communicates its “day-night” signal to the brain and body using a messenger called melatonin, a hormone that is released into the bloodstream by the pineal gland during the night. Melatonin has the task of signaling the arrival of the evening, it is released two hours after sunset, increases rapidly, peaks at 4 in the morning and then slowly decreases until it disappears at dawn.
The second factor is a chemical called “adenosine” that is released into the brain when you are awake, the concentration of which increases as the waking hours pass. The consequence of the increase in adenosine in the brain is the desire to sleep, the so-called ” sleep pressure” .
The peak of adenosine occurs after 12/16 waking hours. It is possible to artificially lower this signal by means of another chemical substance, that is, caffeine (the most widespread psychoactive stimulant in the world). Caffeine blocks adenosine receptors making you feel awake despite the high level of adenosine in your brain. The half-life of caffeine is 5/7 hours, which means that if you drink a cup of coffee at 2.30pm, at 8.30pm 50% of the caffeine will still be active and will circulate in your brain tissues.
What happens in our brain when we sleep? The REM and NREM phase
Sleep is divided into 2 phases: the REM (rapid eye movement) phase characterized by rapid eye movements, a frenetic brain activity similar to that of wakefulness, and the presence of dreams; the NREM (non-rapid eye movement) phase in which the eyes are still and the brain waves have a calm and slow progress.
These two phases alternate overnight with cycles of about 90 minutes. In the first half of the night most of the 90 minutes are occupied by a deep NREM sleep while in the second most of the time is dominated by the REM phase.
This alternation is a way to remodel and update neuronal circuits overnight, that is, to create space for new information and at the same time to retain old information. A key function of NREM sleep (prevalent during the first part of the night) is in fact to remove unnecessary neuronal connections, while that of the REM phase (prevalent in the second part) is, on the contrary, to reinforce the important ones.
Deep sleep with slow waves allows the bark to relax in “default” mode. It is a kind of state of nocturnal brain meditation. The long-range waves that pass through the brain during deep sleep connect different brain centers by implementing a process of transferring memory packets (recent experiences) from a short-term warehouse to a safer, long-term place.
On the other hand, a characteristic of the REM phase is that of connecting recent data with all past experiences, that is of forming a vast network of associations, new insights, new connections from unrelated information. This integration allows us to build a more accurate model of understanding the world. During this phase the body is paralyzed, the muscles are completely relaxed, this atony is a physiological barrier built to prevent the dream experience, so rich in motor impulses, from moving into reality, with the dangers that would ensue.
The beneficial effects of sleep on memory
Of the many benefits of sleeping on the brain, the one on memory is the most impressive. Sleep helps memory both before learning (to prepare the brain for new data) and after learning (to cement new memories and prevent oblivion).
Before learning : sleep reverses the saturation effect of too much information and restores the brain’s learning ability by making room for new memories. This recharge is most effective in the early hours of the morning, in those short periods of light NREM sleep between two longer REM moments, so sleeping six hours or less will deprive you of this restoration of learning.
After learning : sleep protects newly acquired information. This process of memory consolidation occurs during the deep NREM phase, in the first half of the night.
You wake up the next morning able to locate and recover those memory files that previously were not available with such ease and precision.
To forget: in certain contexts, forgetting can be as important as remembering, both in everyday life (forgetting where you parked last week to remember where you parked yesterday) and in clinical cases (removing disabling painful memories or extinguishing craving in addiction disorders). Sleep helps you hold onto what you need and forget what you don’t need or which is harmful.
To improve the memory of motor skills : sleep helps the brain to automate a motor routine such as, for example, performing complex procedures, playing an instrument, playing a sport. During sleep the brain continues to learn even in the absence of exercise. Motor memory works behind the level of consciousness with the result that, after a night of sleep, those skills have become instinctive and flow from the body easily without being the result of deliberate effort.
This advantage in motor memory is obtained during light NREM sleep in the last two hours of sleep, the very two hours that many skip to start their day earlier.
The implications of lack of sleep on concentration, emotional stability and neurological diseases
Lack of sleep has devastating effects on the brain and is linked to numerous neurological and psychiatric conditions (Alzheimer’s, anxiety, depression, bipolar disorder, suicide, stroke, chronic suffering) and physiological (cancer, diabetes, heart attack, infertility, obesity, immuno- deficiency).
The first brain function that collapses after even the slightest sleep deprivation is concentration , with the fatal consequences of sleepy driving. It is a suspension of concentration called micro sleep, which lasts only a few seconds during which the brain becomes unaware of the surrounding world, you have no reactions.
Emotional irrationality: without sleep our brain regresses to a primitive model of uncontrolled reactivity. We produce inappropriate emotional reactions and are unable to place events in a wider context. The brain oscillates excessively between the two opposite states of the spectrum of emotions like those suffering from bipolar disorder. In addition, insufficient sleep increases aggression.
Alzehimer is associated with the production of a toxic protein called beta-amyloid, which is destroyed during the NREM sleep phase, the lack of sleep increases these poisonous proteins that accumulate precisely in the regions that generate NREM sleep causing their degeneration and creating a vicious circle, less sleep = more amloyd = less sleep.
How much it affects sleep on the cardiovascular system, metabolism, diabetes and our immune system
Lack of sleep and cardiovascular system: when we approach middle age the body begins to deteriorate, resilience begins to decline, the impact of insufficient sleep on the cardiovascular system intensifies. Adults over 45 who sleep less than 6 hours are 200% more likely to contract a heart attack or stroke than those who sleep 8 hours.
In addition to speeding up the heart rate and increasing blood pressure, the lack of sleep erodes the tissue of the blood vessels especially those that feed the heart itself, i.e. the coronary arteries, if they narrow or block the heart it can suffer from a fatal attack caused by lack of oxygen.
Lack of sleep produces an increase in the activity of the sympathetic nervous system, which is activated when we have to face a danger, leaving our body in the “fight or flight” mode, this causes: increase in the speed of the heartbeat, hypertension, increase blood pressure and increased cortisol, a hormone that tightens your arteries even more.
Lack of sleep and metabolism, diabetes, weight gain: Lack of sleep weakens the body’s ability to regulate blood sugar causing diabetes. Cells become less receptive to insulin a hormone that regulates sugar absorption. Chronic sleep deprivation has been recognized as a major cause of type 2 (irreversible) diabetes formation in the industrialized world.
Insufficient sleep increases hunger and appetite, impairs the control of impulses within the brain, increases food consumption (especially high calorie food) decreases the sense of satisfaction after eating, and prevents effective weight loss when on a diet.
Lack of sleep and immune system: insufficient sleep dose negatively affects cancer-fighting immune cells. One night of 4 hours of sleep sweeps away 70% of the natural killer cells that circulate in our immune system. Lack of sleep increases the levels of activity of the sympathetic nervous system causing prolonged inflammation of the immune system. Cancer uses the inflammation signal to its advantage, to spread to other areas of the body (metastasis).
Dreaming helps us to eliminate stress and to find solutions by stimulating our creativity
REM sleep can be considered a state characterized by a strong activation of the visual, motor, emotional and autobiographical memory regions of the brain and at the same time by the deactivation of the regions that control rational thinking.
Thanks to a new diagnostic tool, MRI ( magnetic resonance imaging ) we can have a three-dimensional image of brain activity during the REM phase.
Through the combination of careful brain activity measurements and rigorous experimental tests we are finally able to start developing a scientific understanding of dreams.
Dreams feed our mental and emotional health
When we dream, norepinephrine, a stress-related chemical, is completely absent in our brain. REM sleep is the only time of day when the brain is completely free of this anxiety-triggering molecule. The brain during dreams reprocesses the shocking memories of our memory while we are in a state of calm, in a safe environment.
By sleeping you don’t forget the painful memories but you can discard their emotional load, you can relive those memories without regurgitating the same visceral reaction that was present at the time you experienced the trauma. By dreaming you untie the emotion from the experience. If dreams did not operate this form of therapy we would remain in a state of chronic anxiety, trapped in the network of our autobiographical memory.
Dreams help our creativity
Dreams increase the ability to solve problems and find new solutions. During the dream, your brain explores vast areas of knowledge and extracts common rules and points, or “the essence”. You will wake up with a mind capable of finding solutions to problems that seemed impenetrable. The solutions seem to come without effort. Dreams provide a more open and divergent state of information processing, foster associations between distant concepts, new connections.
Dreams question our recent autobiographical experience and skillfully place it in the context of all our past experiences to create a meaningful tapestry.
12 useful tips to follow for a healthy sleep
- Go to bed and wake up at the same time every morning . Sleeping more during the weekend does not compensate for the lack of sleep accumulated during the week.
- Physical activity is highly recommended , but not before bedtime.
- Avoid caffeine and nicotine . It can also take more than 8 hours to get rid of the effects of caffeine.
- Avoid alcoholic drinks before bedtime . Alcohol keeps you in the lighter stages of sleep and when the effect is over you will tend to wake up in the middle of the night.
- Avoid large meals and drinks before bed .
- If possible, avoid medicines that delay or disturb sleep.
- Don’t take naps after three in the afternoon .
- Take time to relax before going to bed , read or listen to music.
- Take a warm bath before bedtime . It will help you relax and lower the temperature.
- Make sure you have a dark , cool bedroom with no objects that distract you from sleep, place alarm clocks and clocks so that you can’t look at the time while trying to fall asleep.
- Get out, expose yourself to sunlight at least thirty minutes a day .
- Don’t stay in bed awake . If you can’t fall asleep after 20 minutes, get up and do some relaxing activities until you get sleepy.