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Sleep Science Research & Tips
Sleep Science Research & Tips

Many of us give up healthy sleep for work or play. In the meantime, research is proving that sleep deprivation cannot be made up for elsewhere. Sleep is essential for health, performance, and even youthfulness.

Sleep Science Research & Tips
Sleep Science Research & Tips

Scientists have paid attention to sleep relatively recently, which is strange if you remember what part of our life we spend in sleep. After the scientific interest in sleep processes arose, so-called sleep centers appeared at Harvard and the University of Pennsylvania, and numerous studies and conclusions were drawn. In this article, you will learn what the science of sleep is, why many people cannot fall asleep, and some practical exercises for healthy sleep and more energy.

First steps in the science of sleep

The pioneer of chronobiology was the French scientist Michel Siffre, who investigated biological rhythms in a rigorous experiment on himself. He lived in an underground cave with a bed, table, chair and telephone to call his research team.

Michelle Siffre
Michelle Siffre

His underground house was lit by only one light bulb with a soft glow. From food - frozen food, several liters of water. There were no clocks, no calendars, and no way of knowing what time it was on the surface, day or night. And so he lived alone for several months.

A few days after descending into the cave, Siffre's biological clock began to work. Later, he recalled how he felt during the experiment:

My dream was wonderful. My body chose when to sleep and when to eat. It is very important. My sleep and wake cycle did not last 24 hours, like people on the surface of the earth, but a little longer - about 24 hours and 30 minutes.

Thus, despite the lack of sunlight and any knowledge of whether it was day or night, his circadian rhythms continued to work.

After this experiment, many scientists became interested in the study of sleep. New research has helped figure out how much sleep you need, why you need to sleep, and how you can make up for your lack of sleep.

How much sleep do you need

How much sleep do you really need? To answer this question, let's turn to an experiment by scientists from the University of Pennsylvania and the University of Washington.

The researchers collected 48 healthy men and women who were accustomed to sleeping 7-8 hours a night. The participants were then divided into four groups.

People from the first group had to stay awake for three days, from the second - to sleep 4 hours a day. Participants from the third group were allowed to sleep 6 hours a day, and from the fourth - 8 hours.

The three groups, who slept 4, 6, and 8 hours a day, were required to follow this regimen for two weeks. During the experiment, the scientists monitored the physical health and behavior of the participants.

As a result, the group of participants who slept for 8 hours a day did not observe any impairments throughout the experiment - a decrease in cognitive functions, a deterioration in reaction or memory lapses. At the same time, all indicators gradually worsened in people who slept for 6 and 4 hours a day.

The group with 4 hours of sleep did worse, although not much, than the 6-hour group. In general, two important conclusions were drawn from the experiment.

First, lack of sleep tends to accumulate. In other words, lack of sleep has a neurobiological cost that only increases over time.

After one week of the experiment, 25% of the participants who slept 6 hours a day periodically fell asleep at different times during the day. After two weeks, people in this group showed the same indicators as if they had spent two days without sleep at all.

Sleep deprivation gradually builds up.

The second conclusion is no less important: the participants did not notice a decrease in their performance. The participants themselves believed that their performance deteriorated for several days and then remained the same. In fact, their performance continued to decline throughout the experiment.

We do not notice a decline in cognitive function with a lack of sleep.

It turns out that we are very poor at assessing our condition and cannot accurately determine how well our cognitive functions are working. Especially in today's environment of constant social activity, caffeine and many other factors that help you feel refreshed and invigorated, even if in reality it is far from the case.

The cost of lack of sleep

The irony is that many of us suffer from sleep deprivation in an effort to earn more. But no matter how many extra hours you spend on work instead of getting a good night's sleep, it won't add much to your productivity. Your attention, memory and other functions deteriorate, and you make all tasks slower and worse.

Research has found that the loss of performance due to lack of sleep is costing US businesses a huge amount. An average of $ 100 billion is lost per year.

Here's what George Belenky, director of the Center for Sleep and Performance Research at the University of Washington, said about it:

If your job is mental, you are paying productivity for your lack of sleep.

After that, a completely logical question arises: how long does it take to sleep in order not to accumulate fatigue and decrease in productivity?

Based on research data, we can say that this time is from 7 to 7.5 hours. Overall, experts agree that 95% of adults need 7 to 9 hours of sleep per night for high performance.

Most adults sleep better for 8 hours a night, and even more for children, adolescents, and the elderly.

How sleep works: sleep and wake cycles

The quality of your sleep is determined by a process called the sleep-wake cycle.

There are two important points in this cycle:

  • The slow-wave sleep phase (also known as deep sleep).
  • REM sleep phase (REM phase, rapid eye movement phase).

During slow-wave sleep, the body relaxes, breathing becomes calmer, blood pressure drops, and the brain becomes less sensitive to external stimuli, making it difficult to wake up.

This phase is of great importance for the renewal and restoration of the body. During the slow phase of sleep, growth hormones are produced in the pineal gland, which ensure tissue growth and muscle repair.

The researchers also suggest that the immune system is restored during NREM sleep. So slow sleep is especially important if you are exercising. Some professional athletes, such as Roger Federer or LeBron James, slept 11-12 hours a day.

Another example of the effect of sleep on physical performance is a study conducted on basketball players at Stanford University. During the exploration process, players slept at least 10 hours a night (as opposed to the 8 hours of sleep they were accustomed to).

The experiment lasted for five weeks, during which the researchers evaluated the speed and accuracy of the players in comparison with their usual results.

It turned out that just two extra hours of sleep increased the number of successful throws by 9% and reduced the time to sprint 80 meters by 0.6 seconds. So, if you have strenuous physical activity, slow sleep will help you recover.

REM sleep is for the mind as much as slow sleep is for the body. Most of the time you sleep, the brain is calm, but when the REM phase comes, it is activated. This is the phase during which you dream and your brain redistributes information.

During the REM phase, the brain erases unnecessary information and improves memory by linking the experience gained in the past 24 hours with previous experience, facilitating learning and provoking the growth of neural connections.

The body temperature rises at this time, blood pressure rises, and the heart beats faster. In addition to this, the body moves. In general, REM sleep occurs three to five times per night for a short period of time.

A person cannot function normally without both phases of sleep. Sleep deprivation affects health: immunity goes down, consciousness becomes "foggy", the risk of infectious diseases increases, blood pressure and the risk of heart disease increase. In addition, sleep deprivation threatens mental illness and shortens life expectancy.

The slow phase of sleep helps to restore physical health, the fast phase - mental capabilities.

However, despite the great importance of sleep for the body, the quality and duration of sleep varies throughout life.

Age-related changes in sleep

Based on research from Harvard Medical School, it can be said that people find it harder to fall asleep as they age. This phenomenon is called sleep delay. And sleep efficiency - the percentage of time you spend in bed while sleeping - also decreases.

On average, 80-year-olds have 62% less long sleep than 20-year-olds. There are many factors that affect tissue aging, and if NREM sleep is shortened, the aging process occurs even faster.

Healthy sleep is your best weapon against aging.

How to recover from a lack of sleep

Most adults need 8 hours of sleep to keep their body readings at their best. Since older people have sleep problems, they can make up for the lack of sleep at night by taking a nap during the day.

In any case, if you realize that you need to take a nap, it is better to do it once in the middle of the day than to fall asleep periodically during the day and evening.

In general, the body recovers well from short-term sleep deprivation. For example, if you had a harsh night when you managed to get 2-4 hours of sleep, the next night 9-10 hours of sleep will completely restore your body.

It's just that your body will spend more time in REM and NREM sleep to recover from the lack of sleep last night.

There is no need to plan how long your body will spend in REM and NREM sleep. It knows better how much sleep and what exactly is needed to recover, so you will not be able to control this process.

And remember that there is no substitute for sleep. If you need to stay awake longer today, make sure you sleep longer than usual the next night.

Circadian rhythms

How are your sleep and wake cycles organized?

Using circadian rhythms. These are biological cycles of different processes that occur within 24 hours.

Here are some of the key points of the 24-hour cycle:

6:00 - Cortisol levels rise to make your body wake up

7:00 - production of melatonin stops;

9:00 - peak production of sex hormone;

10:00 - peak of mental activity;

14:30 - the best level of coordination of movements;

15:30 - best reaction time;

17:00 - the best work of the cardiovascular system and muscle elasticity;

19:00 - highest blood pressure and highest body temperature

21:00 - Melatonin begins to be produced to prepare the body for sleep;

22:00 - the work of the digestive system calms down as the body prepares for sleep;

2:00 - deepest sleep;

4:00 is the lowest body temperature.

Of course, these are only approximate rhythms, since they are individual for each person and depend not only on daylight, but also on habits and other factors.

In general, circadian rhythms are influenced by three main factors: light, time, and melatonin.


Light is one of the most significant circadian rhythm factors. By staying in bright light for about 30 minutes, you can reset your rhythms, no matter what time it is.

In general, when the sun rises and light hits your closed eyes, a signal is given to start a new cycle.


The time of day, your daily schedule, and the order in which you are used to completing different tasks all affect your sleep and wake cycles.


It is a hormone that induces drowsiness and controls body temperature. Melatonin production is dependent on a daily, predictable rhythm. Its amount rises in the dark and decreases when it becomes light.

How to sleep better

Here are some guidelines for falling asleep fast and sound sleep.

Avoid caffeine

If you have trouble sleeping, it's best to eliminate caffeine from your diet altogether. But if you can't turn on in the morning without a cup of coffee, at least don't drink it in the afternoon.

Quit smoking

In the experience of many people who quit or have quit smoking, cigarettes have a negative effect on sleep. After you quit smoking, it will be easier to fall asleep, and the number of awakenings at night will decrease.

Use the bedroom only for sleep and sex

Remove the TV from the bedroom, do not bring a laptop and tablet. The ideal sleeping environment is a dark, cool and quiet bedroom, so try to make it look like this.


Physical activity helps the body and brain turn off at night. This is especially true for older people. Agile, active seniors have been shown to sleep much better. However, between classes and sleep, at least three hours must pass so that the brain and body have time to calm down and prepare for sleep.


Most people fall asleep better in a cool room. The ideal bedroom temperature is 18–21 ° C.


A quiet room is ideal for a great sleep. But if you find it difficult to fall asleep in complete silence, you can turn on white noise.

No alcohol

A small (or very large) amount of alcohol can help you fall asleep, but the quality of this sleep is poor. During this sleep, the REM phase is shortened, so you do not get adequate rest, even if you slept all night.

How to get ready for bed

Here's what you need to do to avoid insomnia.

Set a daily schedule

Our body loves systems. Basically, circadian rhythm is your daily routine at a biological level. Go to sleep and wake up at the same time every day.

Get in the habit of turning off all electronics an hour or two before bed. Light from a computer, TV, or smartphone delays the production of melatonin, which helps the body prepare for sleep.

In addition, working before bed increases brain activity and can increase stress levels, which can have a negative effect on sleep. Instead of reading your work mail, read a paper book. This is a great way to get away from the screen and learn something interesting and useful.

Use relaxation techniques

In 50% of cases of insomnia, researchers say, intense emotional distress and stress are to blame. Find a way to reduce stress and it will be much easier for you to fall asleep.

Proven methods include journaling, breathing, meditation, exercise.

Don't miss the opportunity to take a nap

An afternoon nap helps replenish sleep cycles. This is especially useful for those who can't get enough sleep at night.

How to be more energetic in the morning

Drink a glass of water in the morning

Your body spent 6 to 8 hours without water. Feeling sleepy in the morning (of course, if you have slept enough time) can be caused by a lack of moisture. So a glass of cool water may well refresh you.

Start your day in sunshine

Sunlight in the morning is especially important for your circadian rhythm. The light awakens your brain and body, so you don't even need your morning coffee during the sunny summer months. The main thing is to stay in the light in the morning.


So, the main point of this article is that nothing can replace sleep. If you consciously subject yourself to deprivation, you prevent your brain from working to its fullest and your body from recovering.

Lack of sleep is a barrier between you and your health and productivity. So sleep more.

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