What is melatonin, the hormone of sleep and youth. Why do you need to sleep in the dark, why is it so important? Is it good to sleep in complete darkness?

Modern bedrooms are filled with light - the flickering of a monitor and electronic clock, street lighting. The problem is that constant exposure to light leads to health problems.

To understand why light at night has such a detrimental effect on health, we can look back at history. Until artificial sources of lighting filled human life, he had only two “lamp”: during the day - the sun, at night - the stars and the moon, and, perhaps, light from a fire.

This formed human circadian rhythms, which, despite changes in lighting, still regulate the state of sleep and wakefulness. Today, night artificial lighting breaks centuries-old human habits. It is less bright than sunlight, but brighter than the light from the moon and stars, and this triggers a cascade of biochemical reactions, including the production of hormones such as cortisol and melatonin.

Melatonin and cortisol

Melatonin production is key to understanding why artificial light is so bad for us. This hormone is produced in the pineal gland only in complete darkness and is responsible for the sleep-wake cycle. Melatonin reduces blood pressure, body temperature and blood glucose levels, that is, it does everything to provide the body with a restful, deep sleep.

There is a part of the human brain that is responsible for the biological clock - the suprachiasmatic nucleus in the hypothalamus. This is a group of cells that respond to darkness and light, and gives signals to the brain about when it is time to fall asleep and wake up.

In addition, the suprachiasmatic nucleus is responsible for changes in body temperature and the production of cortisol. At night, the amount of cortisol decreases, allowing us to sleep, and during the day it increases, regulating energy levels.

All these processes are natural, but artificial lighting at night disrupts them. The body reacts to light and increases cortisol levels at night, making it more difficult for a person to fall asleep. Besides, high level The stress hormone reduces the body's resistance to insulin and inflammation. As a result of the fact that cortisol is produced at the wrong time, appetite and sleep are disrupted.

However, hormone levels are regulated not only by the amount of light at the moment, but also by how much light you received before.

Light before bed

Studies have shown that if a person spends time in room lighting before bed, less melatonin is produced for 90 minutes, compared to dim light. If you sleep in room lighting, melatonin levels decrease by 50%.

From this perspective, any light in your bedroom becomes a real problem, and tablets, smartphones and energy-efficient lamps only make it worse. The fact is that Blue light from LEDs is particularly potent in suppressing melatonin production.

Cancer danger

Unfortunately, disruption of hormone production provokes not only bad dream, but also more serious consequences, such as cancer. A 10-year study showed that sleeping in light increases the risk of cancer.

Participants in the experiment who slept in the light were 22% more likely to develop breast cancer than women who slept in complete darkness. Researchers believe this depends on melatonin levels. Even earlier, in vitro experiments proved that melatonin blocks the growth of melanoma cells.

In another study, rats bearing breast cancer xenografts received blood perfusion from women sleeping in bright light and from participants sleeping in complete darkness. Those rats that received blood from the former showed no improvement, while in the latter the tumor decreased.

Based on these studies, we can say that sleeping in the dark is a preventive measure. cancer diseases and all that remains is to sympathize with the people working the night shift.

Dim light, blue light, depression and immunity

Unfortunately, the light in the bedroom at night does not have to be bright to cause damage to health - even dim lighting will suffice. Studies conducted on hamsters have shown that dim lights at night cause depression.

Hamsters exposed to dim lights at night showed less interest in the sweet water they love so much. However, when the lighting was removed, the hamsters returned to their previous state. In addition, constant dim light in the bedroom is bad for the immune system, since melatonin levels decrease, and along with it, immunological indicators deteriorate.

That is, if you have an illuminated electronic clock or other luminous devices in your bedroom that work all night, there is a serious reason to wonder whether you really need them. And this is not to mention the constant light from street lighting that comes through your window when there are no thick curtains.

And more health problems

Melatonin helps fight aging. It protects brain cells from free radicals and prevents degenerative changes. The hormone functions as an antioxidant, which provides protection inside brain cells, and can even be used by people over 40 years of age to prevent Parkinson's disease.

The next problem caused by melatonin deficiency is obesity. Light at night has been proven to promote weight gain by disrupting the body's natural rhythms. Experiments conducted on mice showed that rodents exposed to night light gained weight much faster than those sleeping in the dark, even though the amount of food and activity was the same.

What to do?

To summarize all of the above, we can derive several rules:

1. Remove anything from your bedroom that can glow in the dark, including clocks, electronic devices, gadgets and any relaxing starry lights that you leave on at night.
2. Turn off the lights at night, even the dimmest nightlights.
3. Hang blackout curtains or close blinds to block outside light from entering the room.
4. Don't read on your tablet or smartphone before bed, and don't take them into the bedroom at all.
5. Try to change your job to one where there are no night shifts.

Back in 2000, at an international WHO conference, doctors expressed concern about the increase in cancer, linking it with night lighting, which affects the quality of sleep.

Today we have irrefutable evidence: you need to sleep in the dark at night, sleeping in the light and staying awake at night are fraught with cancer.

Sleep hormone is the key to good health

The hormone melatonin is a natural sleep aid and a regulator of circadian rhythms. It is produced by the pineal gland (pineal gland). When it gets dark, melatonin synthesis increases.

Its increasing entry into the blood helps us transition from active wakefulness to sleep; we begin to experience drowsiness.

The role of melatonin for health is difficult to overestimate:

Regulates circadian rhythms, helps you fall asleep easily and stay active during the day;

Improves mental health, relieves stress;

Normalizes blood pressure;

Protects against DNA destruction, neutralizes free radicals and cancer cells;

Slows down aging, increases life expectancy;

Strengthens the immune system;

Stabilizes hormonal balance and the functioning of the endocrine system;

Reduces the percentage of fat, ensuring optimal weight, subject to normal sleep duration.

The body of an adult produces up to 30 mcg of melatonin per day, 70% of which occurs at night, which exceeds daily synthesis by 30 times. Peak production of the sleep hormone occurs around 2 am, and therefore it is very important to sleep at this time, even if you are a night owl.

With age, melatonin secretion decreases, which can cause insomnia in the elderly.

The lighter the night, the less melatonin is produced

The main enemy of melatonin, and therefore our health, is light at night. Moreover, anyone - from the TV or PC screen, a lantern outside the window, the dial of an electronic alarm clock, etc. You need to fall asleep in complete darkness. Ideal when it is impossible to see your hand (or any object).

If you had to get up and turn on the light at night, the synthesis of the hormone is slowed down, and the body’s debugging is disrupted. As a result, we have trouble falling back to sleep and don't feel fully rested during the day.

Melatonin in sufficient quantities makes our sleep complete, our health strong, and our life active. If there is little sleep hormone, stress, insomnia, and failures in all organs and systems are guaranteed.

Technological progress is destroying our health

With the development of technological progress, humanity has the opportunity to extend daylight hours indefinitely. How did this benefit turn out for people?

First of all, sleep suffered. Insomnia and other insomnias are sweeping the planet, forcing people to buy synthetic sleeping pills, because the natural sleeping pill, melatonin, is produced in insufficient quantities in the light during sleep.

Our sleep is accompanied by lighting from gadgets, lanterns outside the window, and electronic alarm clock dials. Blue light is especially harmful.

Blue light is the enemy of melatonin

Blue light with wavelengths from 450 to 480 nanometers suppresses the synthesis of the sleep hormone the most. As a result, the hand of the biological clock shifts towards the day by approximately 3 hours. For comparison: waves of green light “push back” the night by an hour and a half.

1. In the evening, avoid blue rays so as not to “scare off” your sleep.

2. Before going to bed, wear glasses with amber-colored lenses.

3. Stop watching TV and working at the computer 1 hour before bedtime. There are a lot of blue rays in the spectrum of their screens.

4. Energy-saving and LED lamps have a lot of blue spectrum. Try to buy with pink, “warm” light.

5. Stock up on good old incandescent bulbs while they're on sale and use them around the house in the evenings.

6. There is no place in the bedroom for night lights, electronic alarm clocks, gadgets with blue lamps, numbers, or “eyes.”

In the morning, bright blue light, on the contrary, will help you wake up faster.

How can light interfere, since your eyes are closed during sleep?

Special cells in the human retina are connected by nerve fibers not to the visual centers of the brain, but to the pineal gland, which controls the circadian rhythm and biological clock. The light-sensitive pigment of these cells reacts to any light, which reduces the production of the sleep hormone and leads to disruption of biorhythms.

Melatonin and cancer

Cancer and insufficient sleep are interdependent, Californian scientists said.

People who get a good night's sleep have better immunity to cancer. They produce a sufficient amount of melatonin, an antioxidant that protects DNA from damage.

This hormone inhibits the secretion of estrogen in women, which triggers the formation of cancer cells. Ladies who are awake at night are at risk.

Night lighting provokes the development and growth of cancerous tumors, Israeli researchers (University of Haifa) proved.

Four groups of mice were infected with malignant cells and placed under different light conditions. Tumors progressed rapidly due to a lack of melatonin in mice exposed to light for 16 hours and in those in which the light was periodically turned on during darkness.

Those mice given additional melatonin showed the best results and the lowest mortality, despite 16 hours of daylight.

The scientists' conclusion is disappointing:

Light pollution has become a real environmental disaster for people. Night lighting disrupts biorhythms formed over millions of years of evolution, leading to insufficient production of the sleep hormone, which provokes prostate cancer in men and breast cancer in women.

Summary

Civilization is inexorably destroying human biorhythms, which allowed it to become the largest and most highly adapted population on Earth. It is difficult to resist daily stress, but each of us can go to bed on time and ensure complete darkness in the bedroom (hang dark curtains, turn off gadgets, wear a mask over our eyes, etc.).

I wish you good sleep and good health!

Sources: www.nkj.ru, “Biological rhythms of health” V. Grinevich, Doctor of Medical Sciences.

Healthy sleep is the key to good health and longevity, everyone knows this, but what about the fact that you need to sleep in complete darkness? Scientists from the University of Texas Medical School came to this conclusion, and their study makes you think seriously about your health.

Why is it so important to sleep at night and in the dark?

At the center of the human brain is the pineal gland, which receives signals from the suprachiasmatic nucleus of the brain and is responsible for our circadian rhythms, that is, the sleep-wake cycle.

So, in daytime day, that is, in daylight, the pineal gland produces serotonin - a neurotransmitter substance known to many as the hormone of happiness, and this makes sense, since serotonin is really responsible for our good mood and level of resistance to stress. A lack of serotonin leads to apathy and depression, or vice versa - to aggressiveness and irritability.

At night, the pineal gland begins to produce melatonin, and it is already responsible for proper healthy sleep. It is the production of melatonin that restores our cardiovascular, nervous and immune system, promotes rejuvenation of the body and prolongs our life. A lack of melatonin leads to insomnia, stress, and disruptions throughout the body, which are fraught with serious health problems, in particular, obesity, heart attacks and breast cancer.

The important thing is that melatonin production occurs only at night and only in the dark, most actively between 12 and 2 am. This means that healthy sleep is not in danger if:

• you go to bed after 2.00 and in the morning;
• work night shifts and sleep during the day;
• Get full sleep only on weekends.

Don't be fooled: Melatonin production doesn't last long, it only lasts for a day until your next sleep, so you won't protect your body from damage if you only sleep properly a few days a week. And napping during the day will not provide you with melatonin at all - and this is not healthy sleep at all.

When we are young, we hardly notice the impact of artificial light on the quality of our sleep, but the older we get, the worse we get. Older people suffer from insomnia more often than others, since melatonin production decreases at this age.

How to ensure healthy sleep

Of course, the ideal healthy sleep schedule for our body is to wake up at dawn and go to bed at sunset. But, unfortunately, the urban rhythm of life, active careers and technological progress have led to the fact that few of us can afford such luxury, and what is most dangerous is that we are almost constantly under the influence of artificial light. And this includes not only electric lighting from indoor lamps and street lamps, but also light and glare from computer monitors, televisions, mobile phones, tablets, watches and many other electronic gadgets.

Therefore, in order to ensure healthy sleep in the dark, you will have to make some changes in your lifestyle, namely:

• Remove from the bedroom all lamps and gadgets that may glow or flicker in the dark.

• Hang thick curtains or blinds on the windows - although the light from the moon and stars has little effect on our biorhythms, you should not forget about street lighting.

• Learn to fall asleep without light - no lamps or night lights. If the night lights are lit in the hallway as a last resort, close the bedroom door tightly so that light does not penetrate into the room.

• Go to bed no later than midnight, and preferably at 22-23 hours.

• An hour before bedtime, do not sit at the computer, watch TV, or read from a tablet or smartphone.

• If something continues to interfere, sleep with a thick blindfold. Sleeping in the dark is determined precisely by the signals that the retina sends to the brain, so if you cannot achieve complete darkness, you can try to fool the pineal gland a little. But this does not mean that the deception will succeed if you sleep in a bandage in the morning or during the day - here the body will detect the catch at the level of biorhythms.

• In order not to disturb these biorhythms, you need to not only remember about healthy sleep in the dark, but also about daytime serotonin, without which you won’t get melatonin even with a long night’s sleep. Therefore, be sure to be outside more often, so that during the day you are exposed to sunlight and not artificial light.

• Try not to drink or eat 3-4 hours before bed so that you don't have to go to the toilet and turn on the light at night.

• Avoid drinking alcohol, nicotine and coffee - they reduce melatonin production.

• Introduce into your diet foods that contain the amino acid tryptophan. Thanks to it, both serotonin and melatonin are produced - it is found in beans, nuts, chicken eggs, pumpkin seeds, tomatoes, bananas, corn, rice and lean meat.

And from this video you will learn something more interesting about sleep:

The dark time of day is created for sleep, this is the natural cycle for humans. At night, the activity of organs decreases, cell reactions slow down, and the sleep hormone is released. Disrupting this process even with weak light means exposing your body to unnecessary danger.

Why is it good to sleep in the dark?

The habit of sleeping with the lights off has a beneficial effect on a person’s health, gives strength, and allows you to wake up cheerful and active the next day. In addition, the absence of light during sleep helps prevent depression and drowsiness, maintaining health, beauty and youth longer. Just as negatively as light, a television or a glowing computer screen on a person during sleep has an effect on a person. It's all about the work of the hormone melatonin, which is produced only in the dark. It helps a person fall asleep faster, sleep soundly throughout the night and wake up rested and well-slept. In the light, the hormone melatonin is completely or partially destroyed, the human body does not receive it in full, which causes sleep problems.

It has been observed that the more time a person spends with light during sleep, the higher his risk of developing depression and problems falling asleep. Such people toss and turn in bed, they have negative thoughts, which, coupled with light, prevent them from falling asleep, restless and intermittent sleep appears, and even insomnia may develop. Naturally, after such a difficult night in the morning they feel exhausted, do not perceive what is happening well, are more susceptible to colds and viral diseases, mental disorders, suffer from nervous tension. All these symptoms can appear gradually and very imperceptibly for a person, but, accumulating, they provoke a whole complex of diseases and disorders, the cause of which people may not even notice.

What are the benefits of sleep hormone?

Melatonin is not only a sleep hormone, it also promotes rejuvenation of the entire body. It is thanks to its lack that after 30-40 years people age so rapidly. This situation can be corrected if you take melatonin before bed - this will improve your overall tone, allow you to fall asleep faster and easier, and preserve your youth for a long time. Taking a drug based on this hormone will allow adults to fall asleep peacefully even with the light on. However, this remedy should not be considered as a sleeping pill. If you have insomnia that neither calm walks before bed, nor relaxing procedures or soothing drinks can help you get rid of, it is best to consult a doctor.

Provides adequate sleep restoration of the human body, strengthens his health, increases efficiency. All life processes are subject to biorhythms. Sleep and wakefulness are a manifestation of circadian (daily) surges and declines in the physiological activity of the body.

A good night's sleep is ensured by the hormone melatonin, which is also called the hormone of youth and longevity. If a person has no problems falling asleep, he sleeps in sufficient quantities, the body has a much greater chance of efficiently producing complex biochemical, synthetic reactions aimed at the full restoration of all structures.

General information

Melatonin is the main hormone of the pineal gland, regulator of circadian rhythms. The sleep hormone has been known to the world since 1958; its discovery belongs to the American professor, Aaron Lerner.

Melatonin molecules are small and highly soluble in lipids, which allows them to easily penetrate cell membranes and influence many reactions, such as protein synthesis. In newborns, melatonin begins to be produced only at three months. Before that, they get it through their mother's milk. In the first years of a child’s life, the concentration of the hormone is maximum and gradually begins to decrease over the years.

During the day, the hormone of happiness is active, and with the arrival of darkness it is replaced by the hormone of sleep. There is a biochemical connection between melatonin and serotonin. From approximately 23:00 to 5:00 the highest concentration of the hormone in the body.

Functions of melatonin

Hormone functions are not limited to just managing the processes of sleep and wakefulness. Its activity is manifested in providing other important functions; it has a healing effect on the body:

• ensures cyclical circadian rhythms;
• helps to resist stress;
• slows down the aging process;
• is a powerful antioxidant;
• strengthens immune defense;
• regulates indicators blood pressure and has a beneficial effect on blood circulation;
• controls the functioning of the digestive organs;
• neurons containing melatonin live much longer and ensure full functioning of the nervous system;
• resists the development of malignant neoplasms (research by V. N. Anisimov);
• influences the processes of fat and carbohydrate metabolism, maintains body weight within normal limits;
• influences the synthesis of other hormones;
• reduces pain for headaches and toothaches.

Such actions are provided endogenous melatonin(a hormone produced in the body). Pharmacologists, using knowledge about the therapeutic effect of the sleep hormone, have created drugs containing artificially synthesized (exogenous) melatonin. They are prescribed for the treatment of insomnia, chronic fatigue, migraines, osteoporosis.

The following are used medicines blind people to normalize sleep. They are prescribed to children with serious developmental disabilities (autism, cerebral palsy, mental retardation). Melatonin is used in complex therapy for those who decide to quit smoking (the craving for nicotine decreases). A hormone is prescribed to reduce side effects after chemotherapy.

How and when the hormone is produced

With the onset of darkness, melatonin production begins, by 21:00 its growth is observed. This is a complex biochemical reaction that occurs in the pineal gland (pineal gland). During the day, a hormone is actively formed from the amino acid tryptophan. And at night, under the influence of special enzymes, the joy hormone turns into a sleep hormone. Thus, serotonin and melatonin are connected at the biochemical level.

These two hormones are necessary to ensure the functioning of the body. Melatonin is produced at night; from approximately 11 p.m. to 5 a.m., 70% of the daily amount of the hormone is synthesized.

To avoid disrupting melatonin secretion and sleep, It is recommended to go to bed no later than 10 pm. In the period after 0 and before 4 o'clock you need to sleep in a dark room. If it is impossible to create absolute darkness, it is recommended to use a special eye mask and close the curtains tightly. If you need to stay awake during the active synthesis of a substance, it is better to create dim lighting in the room.

Melatonin is produced in the dark. The detrimental effect of lighting on hormone production.

There are products that catalyze the production of the hormone. The diet should contain foods rich in vitamins (especially B vitamins) and calcium. It is important to balance your intake of complex carbohydrates and proteins.

How it affects the body

Normal concentrations of melatonin ensure easy falling asleep and full, deep sleep. In winter, in cloudy weather, when the amount of light is insufficient, the hormone has a depressing effect on the body. There is lethargy and drowsiness.

In Europe, the Life Extension Foundation is conducting clinical trials using melatonin in the treatment of cancer. The foundation claims that cancer cells produce chemicals similar to pineal hormones. If you influence them with a combination of hormones thyroid gland and melatonin, the body begins actively produce cells for immune defense.

For the treatment of depression, as a prophylaxis for many mental disorders It is enough to sleep or take medications that contain melatonin. It is also important to be in the sun during the daytime.

Experiments on mice

Mice of the same age, to which the cancer gene was introduced, were divided into 2 groups.

One part of the animals was kept in natural conditions; the group had daylight and darkness at night.

The second group was illuminated around the clock. After a while, the experimental mice from the second group began to develop malignant tumors. Studies were carried out on various indicators and it was revealed that:

• accelerated aging;
• excess insulin;
• atherosclerosis;
• obesity;
• high incidence of tumors.

Melatonin deficiency and excess

Consequences of long-term melatonin deficiency:

• at the age of 17, primary signs of aging appear;
• the number of free radicals increases 5 times;
• within six months, weight gain ranges from 5 to 10 kg;
• at the age of 30, women experience menopause;
• the risk of breast cancer increases by 80%.

Causes of lack of sleep hormone:

• chronic fatigue;
• night work;
• puffiness under the eyes;
• sleep disorders;
• anxiety and irritability;
• psychosomatic pathologies;
• vascular diseases;
• stomach ulcer;
• dermatoses;
• schizophrenia;
• alcoholism.

Symptoms of an excess of the hormone are:

• increased heart rate;
• lack of appetite;
• increased blood pressure;
• slow reactions;
• contraction of facial muscles, twitching of shoulders and head.

Excess melatonin causes seasonal depression.

Melatonin tests and norms

The daily norm of the sleep hormone in an adult is 30 mcg. Its concentration by one in the morning is 30 times higher than during the day. In order to provide this amount, eight hours of sleep is required. In the morning, the normal concentration of the hormone is 4-20 pg/ml, at night – up to 150 pg/ml.

The amount of melatonin in the body depends on age:

• up to 20 years of age there is a high level;
• up to 40 years – average;
• after 50 – low, in older people it decreases to 20% and below.

Melatonin does not decrease in centenarians

As a rule, analysis is carried out only by large medical institutions, as it is not a common laboratory test.

Biomaterial samples are taken at short intervals, recording the time of day. The analysis requires special preparation:

• 10-12 hours in advance you should not consume medications, alcohol, tea, coffee;
• It is better to donate blood on an empty stomach;
• For women, the day of the menstrual cycle is important, so you should first consult with a gynecologist;
• You should donate blood before 11:00;
• It is not advisable to subject the body to other medical manipulations and procedures before analysis.

The sleep hormone melatonin does not accumulate. It is impossible to get enough sleep or compensate for the lack of sleep. Disruption of natural daily biorhythms leads to disruption of the synthesis of the substance, and this causes not only insomnia, but also exposes the body to the development of diseases.

The lack of sunlight triggers the body's natural production of melatonin for sleep, disrupting this process and disrupting an important human biological clock.