The Science of Sleep: A Summary of Why We Sleep
Introduction
All living creatures need sleep: but why? Many people fail to acknowledge the true power of sleep. The majority of the people in developed nations fail to obtain the required eight-hour of sleep. This shows how much we neglect sleep.
By the end of this article, you will know how sleep is generated, how it changes across the lifetime, its benefits, and will also debunk many myths that are circulating around the globe. I am sure you will never look at sleep the same way again!
This article is mostly inspired by the excellent book “Why We Sleep” by Matthew Walker. This article will be a brief summary of the book, and I would highly recommend you to get the book to learn about everything sleep has to offer.
Factors Determining Sleep
Two factors determine whether you want to be awake or asleep:
1. The internal 24-hour clock in our brain makes us tired and sleepy at regular intervals of time.
2. Sleep pressure.
1. Circadian Rhythm
A circadian rhythm, or circadian cycle, is a natural, internal process that regulates the sleep-wake cycle and repeats roughly every 24 hours. Every organism that has a lifespan of more than a few days develops the circadian cycle. Wakefulness and sleep are therefore influenced by it.
The concept of a biological clock sitting inside our brain may seem dumb at first, but it does exist. The suprachiasmatic nucleus, composed of ~20000 neurons, is the biological clock sitting right in the middle of the brain. It fetches light signals from the optic nerves and resets the timing inaccuracy (if any) to a 24-hours cycle.
Human body temperature is one of the many other things that the circadian cycle controls. No matter whether you are awake or asleep, this temperature change will take place. The temperature will start to reach its minimum point by midnight, to prepare the body to sleep easily.
Every human has their 24-hours circadian cycle, but the peaks and troughs might be different for different people. Some people are more active during the early morning (morning larks), while some are more active by noon (night owls). Night owls sleep later and are unable to function effectively in the early morning because their prefrontal cortex stays in an offline state, and takes time to start. Night owls generally have difficult lives, not because they are different, but because our society doesn’t treat them fairly. A lot of the time, night owls are genetic. Night owls are often labeled “lazy”. Morning larks rule the morning office hours, and the owls hardly get a chance to show their full potential. They are also more likely to suffer from depression and anxiety. A change in societal change is required to provide equal opportunities for night owls.
Melatonin, the hormone of darkness, is a chemical that is released at night. The rise in melatonin begins soon after dusk. It is secreted by the pineal gland. It signals the body to sleep, and it is the main messenger that the suprachiasmatic nucleus uses to communicate its repeating signals of day and night. Interesting to note, melatonin has little-to-no effect on the generation of sleep itself. Hence, melatonin pills are not ideal sleeping aids for healthy, non-jet lagged individuals.
Melatonin concentration starts to fade away once sleep is underway. As dawn arrives, a brake pedal is applied to the pineal gland; shutting off the release of melatonin. Below is the rise-and-fall graph of melatonin.
2. Sleep Pressure
A chemical called adenosine keeps building up in the brain with every minute you have been awake. The longer someone is awake, the more adenosine will get accumulated. An increase in adenosine increases the desire to sleep. This is known as sleep pressure. High concentrations of adenosine turn down the volume of wake-promoting regions in the brain and turn up the dial on sleep-inducing regions.
Once sleep is underway, the body gets the chance to remove the day’s adenosine. After approximately eight hours of sleep in an adult, the adenosine purge is complete.
Process Independence
You might be thinking the circadian rhythm and adenosine communicate with each other to make you fall asleep at a specific time, but they don’t. They are different systems and ignorant of each other.
The above figure shows the up-and-downs of the two processes. Process C is the circadian rhythm and Process S is the level of adenosine. The greater the distance between process C and S, the greater is the urge to sleep.
Affecting Your Sleep Rhythm
Have you been unknowingly affecting your sleep rhythm?
Jet Lag
If you have traveled between time zones, you probably felt it hard to fall asleep at night. Jet planes have allowed us to speed past time zones; faster than our 24-hour clocks could ever keep up or adjust to. This is jet lag.
As a result, you might find it extremely hard to function during the day at a different time zone, and also extremely difficult to fall asleep at night. The circadian rhythm will adjust eventually, but it is a very slow process. For every day you are in a different time zone, your suprachiasmatic nucleus can only readjust by about one hour. The brain will acclimatize to the new time zone by way of the sunlight signals.
Melatonin pills may fool the brain into thinking it is night time. Even though the act of generating sleep would be difficult at that irregular time, this timing signal (melatonin) may significantly increase the likelihood of sleeping in this jet-lag context.
Jet lags are stressful for cells, and major systems of the body. People who face frequent jet lags, such as pilots and aircrew, are at higher risks of developing cancer and type 2 diabetes than non-jet-lagged individuals. Also, some parts of the brain in frequent jet-lagged individuals physically shrink, especially those related to learning and memory.
Caffeine
It may anger some of the coffee lovers now. Caffeine mutes the sleep signal of adenosine by latching on to adenosine receptors. Once caffeine occupies these receptors, it blocks and inactivates them. Caffeine tricks you into feeling alert and awake.
Level of circulating caffeine peaks after thirty minutes of oral administration. It can take up to ten hours to completely remove caffeine from your bloodstream. Caffeine is removed from your body by an enzyme within your liver, CYP1A2, which gradually degrades over time as you age. Solely depending on genetics, some people may have a more effective version of this enzyme.
If you are trying to stay awake by consuming caffeine, you must be ready for a caffeine crash. When your liver successfully evicts the caffeine, all the adenosine will again try to force you into sleep.
Types Of Sleep
When you fall asleep, you become unaware of your surroundings. All the sensory signals still flood into the center of your brain, but they are blocked by the thalamus while you sleep.
Humans (and many other animals) don’t just sleep but cycle through two different types of sleep, REM (rapid eye movement) and NREM (non-rapid eye movement) sleep. REM sleep is related to the experience we call dreaming and is known as dream sleep. NREM sleep divides into four stages, NREM sleep stages 1 to 4. Stage 4 is the deepest stage, with “depth” referred to as the difficulty in waking up individuals from that stage of NREM sleep.
The Sleep Cycle
The battle of NREM and REM sleep dominance is won and lost every ninety minutes (cycle length may differ in different species), ruled first by NREM sleep and then a comeback by REM sleep.
You may not see a regular pattern because whenever the brain flip-flops from REM and NREM sleep, the ratio of NREM to REM sleep dramatically changes across the night. Cycle 5 is composed of REM-rich sleep.
A function of deep NREM sleep is to weed out and remove unnecessary neural connections. The dreaming stage of REM sleep helps strengthen those connections.
If you decided to cut your eight hours of sleep by two hours, you might think you are just sleeping 25% less, but a mass proportion of required REM sleep will be lost.
When you are awake, fast-frequency brain waves will be recorded, around thirty or forty times per second.
When you enter deeper stages of NREM sleep, slow-frequency brain waves will be recorded, around two to four times per second. Slow waves of NREM are far more synchronous and reliable than those of waking brain activity. Deep-sleep brainwaves will travel in one direction: from the front of your brain to the back of your brain.
During REM sleep, some parts of your brain are 30% more active than when you are awake! REM sleep is also called paradoxical sleep: a brain that looks awake but a body that is clearly asleep.
The sensory gates of the thalamus open during REM sleep but function differently. Instead of allowing outside sensations, signals of emotions, motivations, and memories are all played in the sensory cortices in the brain.
Just before the dreaming phase begins, you will be completely paralyzed as a safety mechanism to prevent you from acting out your dreams. This paralysis mechanism can fail in some people, especially when they age.
Who, How, and How Much?
Who Sleeps?
Without any exceptions, every animal species studied to date sleeps or engages in something remarkably like it.
How Much Sleep?
Elephants need just four hours of sleep. Humans eight. Why does such a huge variation exist? Researchers are not sure about the exact reason. For now, the most accurate estimate of why different species need different sleep amounts involves a complex hybrid of factors — dietary type, metabolic rate, nervous system complexity, nature of the social network, etc.
Who Dreams?
Not all species experience all the stages of sleep. Every species scientists have observed to date experiences NREM sleep. Insects, amphibians, fish, and most reptiles show no clear signs of REM sleep. It can be concluded that NREM sleep was the first to appear in evolution.
Uni-Hemispheric Sleep
Not all animals sleep the same way. Whales and dolphins, who only experience NREM sleep can sleep with just half a brain at a time, i.e. uni-hemispheric. One-half of their brain stays awake to main life-necessary movement in the aquatic environment. Birds can too experience split-brain deep NREM sleep.
Humans show a mild version of uni-hemispheric sleep. When you bring someone to a foreign environment (like a hotel room), one-half of their brain will sleep a little lighter than the other.
Humans Aren’t Sleeping Right!
Humans are not sleeping the way nature intended. The number of sleep bouts, duration, and sleep time all has been distorted by modernity.
Most humans sleep in a monophasic pattern, that is, taking a long, single sleeping session at night.
Humans should be sleeping in a biphasic pattern. A sleeping session as night as usual, with a short evening nap in addition. Our lives are shortened when we sleep in a monophasic pattern.
We Are Lucky
Humans sleep comparably less than primates, who require nine to fifteen hours of sleep every day. As if evolution decreased our sleep duration but increased its intensity. It enriched the amount of REM sleep we pack into our nights.
Sleep Across The Life Span
Sleep Before Birth
Before birth, a human fetus will spend almost all of its time in a sleep-like stage, much of which resembles the REM-sleep state. Of the total twenty-four-hour in a day, the baby will spend approximately six hours in NREM sleep, six hours in REM sleep, and twelve hours in an intermediary sleep state that we cannot confidently say is REM or NREM. REM sleep dominants most of the early development life, because in this stage, the brain is undergoing the greatest construction. An infant’s brain without sleep (especially REM) will be a brain under-constructed.
Alcohol consumed by a mother readily crosses the placental barrier, and therefore infuses with her developing fetus. Fetus of heavy-drinking mothers do not have the same electrical quality of REM sleep, and that hampers the brain development from an early point in life.
REM sleep is not optional during the early development of life, it is obligatory! And disturbances in the way of getting REM sleep will distort brain development.
Childhood Sleep
Infants and young kids display polyphasic sleep, i.e. sleeping multiple times through the day and night. By three or four months of age, the circadian rhythm will start governing the newborn modestly. By four years of age, the circadian rhythm will take dominant command over the child’s sleeping behavior.
During fourteen hours of total sleep per day that a six-month-old infant obtains, there will be a 50/50 timeshare between NREM and REM sleep. It will stabilize to 80/20 NREM/REM split by the late teenage years. REM sleep plays a major role in populating brain neighborhoods with neural connections.
Adolescence Sleep
During adolescence years, there will be a decline in REM sleep and a significant increase in NREM sleep. NREM sleep scales back for efficiency, refinement, and effectiveness in the neural connections. Deep sleep may be a driving force of brain maturation.
During puberty, the timing of the suprachiasmatic nucleus gets shifted progressively forward. So forward that it even passes the timing of the adult parents. Evolution-wise, it might be programmed by mother nature to allow teenagers to have some free time without their parent’s supervision.
Telling a teenager to go to sleep at ten p.m. is the circadian equivalent of telling an adult to go to sleep at seven or eight p.m. Even if they go to sleep early, chances are they will lie in their bed for a long time. No matter what the adults may say, the circadian rhythm will not miraculously change. As they age, their circadian rhythm will slide backward.
Midlife And Old Age Sleep
Older adults appear to need just as much sleep as they do in midlife, but are simply less able to generate that sleep.
Contradictory to REM sleep which remains largely stable during midlife, a decline in NREM sleep is already underway in your twenties and thirties. You will obtain fewer hours of deep sleep, and those brainwaves will become fewer in number, more fragile, and less powerful. By the age of seventy, you will have lost 80 to 90 percent of your youthful deep sleep.
Additionally, the other factor that affects the quality of sleep in old adults is frequent visits to the bathroom due to weaker bladder.
Just because old individuals cannot generate the required amount of sleep, doesn’t mean that they require less sleep.
Benefits Of Sleep
We started with which body functions are improved by sleep, and now scientists are struggling to find a function that isn’t improved by sleep.
Sleep For Learning
Sleeping before learning something will refresh your ability to store new information. Hippocampus is a region in the brain that apprehends fact-based information. But the hippocampus has a limited storage capacity, and once exceeded you will find it extremely difficult to add new information into it. The memory refreshment is linked to NREM (stage 2) sleep. The information will get shifted to the long-term cortex from the hippocampus.
Sleeping after learning effectively clicks the “save” button. Again, NREM sleep plays a major role here.
Sleep For Other Types Of Memory
Sleep also plays a major role for motor-skill enhancement. This ability is also linked to stage 2 NREM sleep, especially the last two hours of an eight-hour night of sleep. It also enhances your ability to play musical instruments.
Sleep is essential for athletic development across all sports. Not getting enough sleep imposes an injury risk.
Post-performance sleep accelerates physical recovery from common inflammation, stimulates muscle repair, and helps restock cellular energy in for of glucose and glycogen.
Sleep For Creativity
Sleep, the REM sleep, enhances creativity. A lot of revolutionary ideas came to people while they were asleep. Consider Dmitri Mendeleev for example. The brain creates connections between vast stores of information while you sleep.
Sleep Deprivation: Risks and Effects
Lack of sleep will kill you, and in a lot of ways!
Accidents
Sleep deprivation is a major cause of motor vehicle accidents, and it can affect the human brain as much as alcohol can. Microsleeps last for a few seconds during which the eyelids will partially or fully close, and this makes the brain blind to the outside world. Microsleeps occur frequently in sleep-deprived individuals.
Not sleeping for nineteen hours will make you as cognitively impaired as being legally drunk (blood alcohol concentration of 0.08).
Just like a drinker who says “I am fine. I can drive home safely”, sleep-deprived individuals don’t know how sleep-deprived they are! With chronic sleep restriction over months or years, an individual will actually accumulate to their impaired performance, low level of alertness, and reduced energy.
Emotional Irrationality
The amygdala, a structure located in the left and right sides of the brain, is a key hot spot for triggering emotions. It shows a 60 percent rise in emotional reactivity when sleep-deprived.
The prefrontal cortex, the region associated with rational, logical thought and decision-making, is strongly coupled with the amygdala. Without sufficient sleep, the strong coupling between these two regions gets lost.
The striatum is a deep emotional center in the brain associated with rewards (and dopamine bathing), located above and behind the amygdala, which gets hyperactive in sleep-deprived individuals.
Sleep deprivation does not push the brain into a negative state; it makes it swing excessively to both extremes of emotions.
Alzheimer’s Disease
Alzheimer’s disease is still under research, but we can make a fair deal that sleep disturbances precede the onset of Alzheimer’s disease. Alzheimer’s disease is associated with the buildup of a toxic form of a protein called beta-amyloid.
Cerebrospinal fluids bathe the brain. The glial cells of the brain shrink in size during NREM sleep, allowing the fluid to proficiently clean out metabolic debris. Without sufficient sleep, amyloid plaques will build up in the brain; which further restricts your ability to get enough sleep.
We can conclude that getting too little sleep across the adult life span will significantly raise your risk of developing Alzheimer’s disease.
Cardiovascular System
Shorter sleep was associated with a 45 percent increased risk of dying from cardiovascular disease within seven to twenty-five years of the study.
The reason why the heart suffers so drastically might be related to blood pressure. Even one night of insufficient sleep will significantly increase the systolic blood pressure within their vasculature.
The sympathetic nervous system enters its “on” stage when it senses danger, but left on that “on” state for a long time, and it becomes a killer! Deficient sleep has observed an overactive sympathetic nervous system. When the body enters the fight-or-flight state, the heart will beat faster. The rate of blood pumped through your vasculature increases, and that may cause a hypertensive stage of your blood pressure. A chronic increase in the stress hormone cortisol will constrict the blood vessels making matters worse.
Diabetes
Blood sugar causes surprising harm to the tissues and organs of your body.
Getting insufficient sleep will make your cells far less receptive to insulin. The cells will resist the message from insulin and will repel rather than absorb the excess glucose.
Weight Gain
There are two hormones controlling appetite: leptin and ghrelin. Leptin triggers a sense of “full” while ghrelin triggers a sensation of hunger. An imbalance of either one of these hormones can trigger increased eating and thus body weight. Insufficient sleep is also linked to a greater craving for sweets.
Not getting enough sleep will increase the concentration of ghrelin while suppressing the companion hormone, leptin.
Reproductive System
Sleep is necessary to stay fit and hope for reproductive success. Sleep-deprived men have a 29 percent lower sperm count than well-slept men.
Low testosterone is a clinically concerning and life-threatening matter. Males with low testosterone feel tired throughout the day. Testosterone maintains bone density and plays a role in building muscles.
For women, routinely sleeping less than six hours a night results in a 20 percent drop in follicular-releasing hormone. Women not getting enough sleep have a 33 percent higher rate of abnormal menstrual cycles. Not getting enough sleep also reduces their ability to get pregnant and are more likely to suffer discouragement in the first trimester.
Immune System
Sleep deprivation will diminish one form of macrophages, the M1 cells, that help combat cancer while boosting another form of macrophages, the M2 cells, that promote cancer growth.
Sleep also enhances other immune functions that allow the body to fight against other diseases, and also improves the effectiveness of vaccines.
DNA And Genes
Sleep loss erodes your genetic code and structures. Thousands of genes within the brain depend upon sleep for their stable regulation. Reduced sleep can distort the activity of genes (take hefty 711 as an example).
A decrease in sleep will cause a drop in high-density lipoproteins which is linked to cardiovascular diseases.
Sleep Disorders
Some, out of hundreds, of the sleep disorders, will be discussed here. You should go to a sleep doctor as soon as possible if you think you might have one of them or the others.
Somnambulism
Somnambulism is a sleep disorder related to some form of movement. It may include sleepwalking, sleep talking, sleep eating, sleep texting, and very rarely, sleep homicide. All these events arise from the deepest stage of non-dreaming NREM sleep.
What causes somnambulism? We do not fully know yet. Maybe a sudden unexpected spike in nervous system activity during deep sleep signals the brain to a state of wakefulness. But it gets stuck somewhere in between sleep and wakefulness. In this mixed consciousness, the brain performs basic but well-rehearsed actions.
Insomnia
Insomnia is not the same as being sleep-deprived. People with insomnia fail to generate an adequate amount of sleep.
One distinction separates insomnia into two kinds. People with insomnia may have one or both of them together.
- Sleep onset insomnia: Difficulty falling asleep.
- Sleep maintenance insomnia: Difficulty staying asleep.
Insomnia is a complex sleeping disorder, also one of the most common. Sleeping pills are no longer recommended (and we will see why a bit later) as an effective treatment for insomnia.
Narcolepsy
Narcolepsy is a sleep disorder that causes excessive daytime sleepiness (don’t confuse it with sleep deprivation, again), sleep paralysis, and cataplexy. The condition usually emerges between the age of ten to twenty.
Sleep paralysis is the temporary loss of ability to talk or move when waking up from sleep. It feels like being locked inside your body. Most of these events occur during REM sleep when the brain paralyzes the body to prevent it from acting out dreams. On rare occasions, the paralysis of the REM sleep lingers on even after the brain has terminated sleep. Sleep paralysis is common, and not unique to narcolepsy.
A cataplectic attack is a sudden loss of muscle control. It may be as simple as a jaw drop to as severe as a total loss of muscle tone. Cataplectic attacks are not random but triggered by moderate or strong emotions, positive or negative.
What causes narcolepsy? Might be a lack of orexin and a reduced number of receptor sites. With little orexin, the sleep-wake cycle of the narcoleptic brain is very unstable. The orexin-deficient state is the cause of such excess daytime sleepiness and surprise attacks of sleep.
Fatal Familial Insomnia (FFI)
Fatal familial insomnia (FFI) is a rare genetic degenerative brain disorder. The culprit is an anomaly of a gene called PrNP, which stands for prion protein. Prion proteins perform useful tasks in our brain, but a genetic defect makes them rogue.
One region the prion proteins attack is the thalamus; the sensory gate that closes for wakefulness to end and sleep to begin. When prion proteins attack it, the thalamus gets permanently stuck in an “on” state over time.
Myths
You only need 6.75 hours of sleep
People tend to argue about how tribe people can sleep 6 hours a night and still be fit and physically active. But here comes the catch. Most tribe people die before reaching the age of sixty, and the most common reason for death is infections which can be related to sleep deprivation.
If sleeping 6.75 hours a day can lead to a shorter lifespan and weaker immune system, then why do hunter-gatherers and tribe people sleep so little? One reason could be limited food. All animals can be forced to sleep less by making them starve. Hunter-gatherers spend the majority of their waking hours hunting for food to make up for their daily calorie intake.
In conclusion, humans need less than seven hours of sleep is a myth.
Pills vs Therapy
Sleeping pills do not induce natural sleep, damages health, and increase the risk of life-threatening diseases.
Dark Side: The Only Side Of Sleeping Pills
No past or current sleeping medication induces natural sleep. Sleeping pills target the receptors in your brain (that alcohol does) and thus stop the neurons from firing. Sleeping pills are sedatives. The electrical quality of sleep induced by pills is not the same as natural sleep. Adding on to it side effects such as daytime forgetfulness, performing actions at night, and slowed reaction time also come along. If that is not enough, individuals suffer far worse sleep quality when they stop taking the pills. It creates a dependency cycle.
Sleeping pills only produce a slight improvement in the time required for individuals to fall asleep, but come with many disadvantages. There are no objective benefits of sleeping pills beyond that which a placebo can offer.
Pills-induced sleep not only fails to match the benefits of natural sleep but also causes a 50 percent weakening of the brain cell connection originally formed during learning. People who take pills may wake up with fewer memories of yesterday.
If that still did not change your mind, individuals who take sleeping pills are more likely to die or develop cancer than those who do not.
Therapy
There are numerous effective behavioral methods for improving your sleep. The most effective, currently, is CBT-I (Cognitive Behavioral Therapy). The cognitive part of CBT-I teaches you to recognize and change beliefs that affect your ability to sleep. This type of therapy can help you control or eliminate negative thoughts and worries that keep you awake.
The methods involve reducing caffeine and alcohol intake, removing screens from the bedroom, having a cool bedroom, establishing a regular bedtime and wakeup time, going to bed only when sleepy, avoiding daytime napping, etc.
Results from around the globe have now demonstrated CBT-I as more effective than sleeping pills in addressing numerous sleeping problems, including insomnia.
Sleep And Modernity
So far, you might have already noticed how bad of influence modernity has on sleep.
Work
Sleep-deprived employees do not bring much value to the company as individuals who achieve their required eight-hour sleep. Due to work pressure, employees hardly get the opportunity to fulfill their sleep requirements.
Sleep-deprived individuals take a longer time to complete a task, have decreased creativity. They are not suitable to work in teams since they lose self-control and become more abusive.
Organizations should encourage their workers to arrive at work after having well-rested with the required eight-hour sleep.
Education
The majority of high schools start before 8:30 am, some even as early as 5:20 am. 5:20 am is not the same to a teenager as to an adult. As discussed earlier, the circadian rhythm in teenagers is shifted two to three hours past their parents’. Would an adult be able to concentrate after being forcefully woken up at 3:20 am day after day?
Teenagers receive most of their REM sleep in the last two hours of the eight-hour sleep duration. When they wake up early, they fail to obtain REM sleep. REM sleep is what stands between rationality and insanity. That may explain why many teenagers develop mental illnesses and get irritated easily.
Some schools have already understood this problem and shifted their start time by one to two hours. With this slight change, the students secured better marks and got more creative. Not only this, the life expectancy of the students increased, and accidents involving students decreased. Forcing youthful brains to become early birds will guarantee they do not catch the worm.
Health Care
Medical errors are the third-leading cause of death among Americans after heart attacks and cancer. Medical staff working thirty-hour-long shifts will commit 36 percent more serious medical errors. So the next time you visit a doctor for surgery, the doctor’s sleeping duration in the last twenty-four-hour will be a decisive factor in the success of the procedure.
Doctors, nurses, and staff in hospitals should get the opportunity to be fully rested every day and must avoid long shifts without breaks. Not only for the patient but it is also hazardous for the sleep-deprived worker!
LEDs And Electronics
Light Emitting Diodes, or LEDs in short, have grown in popularity over the past few years are said to be 90 percent more efficient than incandescent light bulbs. The light receptors in the eye that communicates the signal of “daylight” to the suprachiasmatic nucleus are most sensitive to the short-wavelength light within the blue spectrum — the exact sweet spot where blue LEDs are most powerful. Blue LED light has twice the harmful impact on nighttime melatonin suppression than the warm, yellow light from old incandescent bulbs. Besides that, regularly using portable electronic devices like iPads an hour or less before sleep has an impact on your melatonin releases.
On average, evening electric light winds back the internal twenty-four-hour clock to two to three hours each evening. When you turn off the bedside light and try to fall asleep, you will find it difficult to sleep. Instructed by the darkness, it will take some time for the tide of melatonin to submerge your body.
We should try to limit artificial evening light exposure. A good is to create a lowered, dim light in the rooms where you spend your evening hours. You can also install software on your devices that gradually de-saturates the harmful blue LED light as the evening progresses.
Alarm Clocks
Alarm clocks. We all use them. No other species demonstrates this unnatural act of prematurely and artificially terminating sleep. People artificially wrenched from sleep will suffer a spike in blood pressure and a shock acceleration in heart rate caused by an explosive burst of activity from the flight-and-flight nervous system.
What is more dangerous is the snooze button. Using the snooze button feature repeatedly inflicts that cardiovascular assault again and again within a short period. Do it regularly, and you can imagine the torture on your heart and your nervous system across your life span.
With busy schedules, it is very hard to wake up without alarm clocks. But here are some things you can do: 1) Never use the snooze button. 2) Choose an alarm with a soft and peaceful sound. 3) Sleep somewhere where the sunlight will strike your body when the sun rises.
For Better Sleep
Here are some tips for better sleep from Sleep Foundation and ThenSF.
Conclusion
Evolution spent millions of years perfecting the art of sleep. Disturbances in sleep caused by modernity are causing health-related issues. Do not get offended if someone calls you lazy for getting your required eight or nine hours of sleep. I bet you will never look at sleeping the same way again. Sleep well!
