home Analyzes Why should you sleep in the dark? Why should you sleep in total darkness?

Why should you sleep in the dark? Why should you sleep in total darkness?

It would seem, what difference does it make to sleep with or without light - if the dream is strong, then what will prevent it? But scientists and doctors say that sleeping in the light can significantly harm health. Let's see what the consequences of sleeping with the lamp on can be, and how to ensure a healthy sleep.

Are you used to falling asleep watching TV? Do you have a night light on or is your digital clock constantly on? Do the curtains let in the light of street lights and signs? It turns out that this is a cause for serious concern. Thus, the sleep specialist Dr. Kenji Obayashi from medical university Napa says that as a result of a series of experiments, it turned out that sleeping in the light can be fraught with insomnia, a violation metabolic processes in the body, the appearance of excess weight, cardiovascular diseases, the appearance mental disorders, depression and even manifestations of suicidal tendencies.

The sphere of sleep is not yet fully understood, and there is still a lot of incomprehensibility in it, however, scientists have found that during sleep in the light, disturbances in circadian rhythms occur that regulate the change of periods of wakefulness and sleep, and others. physiological processes(the so-called "internal clock" of a person).

To understand what caused this, let's turn to the life of our ancient ancestors. During the day, the sun was the only source of light for man, but at night only the moon and stars shone. Only a fire could provide artificial light. Thus, for centuries, the very circadian rhythms that “force” us to be awake during the day and sleep at night have been formed.

However, with the invention of electricity, age-old habits began to change rapidly. These changes have become especially strong with the advent of televisions and computers. Today, they are in almost every home, and in most cases, the process of falling asleep is accompanied by a TV flicker. Artificial lighting is brighter than the light of the moon and stars, so the body "fails in the program", and starts a number of biochemical reactions that subsequently negatively affect our health.

One of these reactions is an imbalance in the hormones cortisol and melatonin.

Lighting your bedroom at night causes hormonal changes

The hormone melatonin is the regulator of our circadian rhythms. The production of this hormone is directly dependent on the level of illumination. About 70 percent of melatonin secretion occurs at night. It helps to reduce blood pressure, glucose levels, body temperature, providing our body with a deep healthy sleep.

It has been proven that an excess of light inhibits the synthesis and secretion of melatonin, and a decrease in light, on the contrary, contributes to its active production.

Artificial lighting disrupts the balance of another hormone, cortisol, which normally decreases at night and rises during the day. Light at night knocks these processes down, and it becomes much more difficult for a person to fall asleep. Moreover, due to an excess of cortisol, the anxiety hormone, not only sleep is disturbed, but also appetite, which will subsequently contribute to the formation of extra pounds.

It is worth noting that the hormonal background is affected not only by the level of illumination during sleep, but also by how much light has affected our body before. note that blue light particularly strongly inhibits the production of melatonin.

Is dim and weak light in the bedroom dangerous during sleep?

During sleep, not only bright light is dangerous to human health. Even dim lighting negatively affects the mental state.

So, studies conducted on hamsters have shown a relationship between light at night and the development of depression. For several nights in a row, hamsters were illuminated with a dim color, after which the animals lost interest in their favorite treat - sweet water- V daytime. After the hamsters began to sleep again in the dark, the old addictions returned, and they drank sweet water with pleasure.

The human immune system can also be affected by improper lighting during sleep. The hormone melatonin is associated with immunological parameters, which deteriorate significantly with a decrease in its production.

Thus, the luminous display of any electrical appliance at night disrupts sleep and normal functioning organism. You need to take care of thick curtains that do not let in the light of lanterns and signs from the street, as well as remove all luminous devices from your bedroom during sleep.

What health problems can result from too much light during sleep?

It is believed that excessive lighting can provoke the development of cancer. Violations hormonal background simply can not pass without a trace for the body. One of the most serious health consequences is the increased risk cancer.

This was confirmed Scientific research duration of 10 years. During the experiment, one group of women slept in the light, and the other in the dark. As a result, the risk of breast cancer in the first group was 22% higher than in the second. Scientists believe that the reason for this relationship is again melatonin. Earlier experiments demonstrated the ability of melatonin to block cell growth. malignant tumor melanoma.

Melatonin also helps in the fight against aging. It has a protective effect on brain cells, blocking the action free radicals and preventing degenerative changes. This hormone is even used by people over the age of forty to prevent Parkinson's disease, due to its pronounced antioxidant effect and the ability to provide protection inside human brain cells.

IN modern world The problem of obesity has become very common and one of the many reasons for this phenomenon can be considered a factor of melatonin deficiency. Sleeping in the light at night disrupts the natural rhythms of man, hormonal balance and metabolic processes. As a result of such violations, excess weight.

Scientists have experimentally proven the relationship between sleep and weight. The study was conducted on mice. It turned out that rodents that slept in the light gained weight much faster than mice that slept in the dark. At the same time, the amount of food, water and physical activity all rodents were the same.

What to do? How to avoid all these problems?

1 If possible, do not work in night shift. If such work cannot be avoided, be sure to sleep with closed blackout curtains on the windows. During sleep, your room should be dark.
2 Remove all gadgets that glow in the dark from the bedroom. Night lamps with dim light will also have to be hidden. Minimum light in the room!
3 Make sure that the light of street lamps and neon signs does not penetrate your bedroom. Dark curtains made of thick fabric or blinds will help you with this.
4 Break the habit of reading on your tablet before bed. In general, leave your smartphone, computer, and tablet out of your bedroom whenever possible.
5 If it is impossible to achieve complete darkness in the room during sleep, you should use a special blindfold.

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

To understand why light at night is so detrimental to health, you can turn to history. Bye artificial sources lighting did not fill the life of a person, he had only two "lamps": during the day - the sun, at night - the stars and the moon, and, perhaps, the light from the fire.

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

melatonin and cortisol

The production of melatonin is the key to understanding why artificial lighting is so bad for us. This hormone is produced in pineal gland only under the condition of absolute darkness and is responsible for the cycle of sleep and wakefulness. Melatonin lowers blood pressure, body temperature and blood glucose levels, that is, it does everything to provide the body with restful, deep sleep.

There is a part of the human brain that is responsible for The biological clock- suprachiasmatic nucleus in the hypothalamus. This is a group of cells that reacts to darkness and light and signals to the brain 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. IN dark time During the day, the amount of cortisol decreases, allowing us to sleep, and during the day it rises, regulating energy levels.

All these processes are natural, but artificial lighting at night knocks them down. The body reacts to light and raises cortisol levels at night, making it harder 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 disturbed.

However, the level of hormones is regulated not only by the amount of light in this moment, but also by how much light you received before.

light before bed

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

From this angle, 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 strong at suppressing melatonin production.

The danger of cancer

Unfortunately, a violation of hormone production provokes not only bad dream, but more serious consequences, for example, cancer. Over the course of 10 years, a study was conducted that proved that sleeping in the light increases the risk of getting cancer.

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

In another study, rats with breast cancer xenografts received blood perfusion from women who slept in bright light and from participants who slept in total darkness. In those rats that received blood from the former, no improvement was observed, while in the latter, the tumor decreased.

Based on the data of these studies, we can say that sleeping in the dark is the prevention of cancer and one can only sympathize with 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. Hamster studies have shown that dim lights at night cause depression.

Hamsters, illuminated at night by dim lights, 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, the constant dim light in the bedroom is bad for the immune system, as the level of melatonin decreases, and with it the immunological parameters worsen.

That is, if you have a digital clock with a backlight or other luminous devices in your bedroom that work all night, there is serious occasion think about whether you really need them. And that's not to mention the constant light from the street lighting, which penetrates your window when there are no thick curtains.

And more health problems

Melatonin helps fight aging. It protects brain cells from the effects of free radicals and prevents degenerative changes. The hormone acts as an antioxidant that provides protection inside the brain cells, and can even be used by people over 40 as a prevention of Parkinson's disease.

The next problem from a lack of melatonin 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 nighttime lighting gained weight much faster than those sleeping in the dark, although the amount of food and activity was the same.

What to do?

Summarizing all of the above, we can derive several rules:

Remove anything from your bedroom that can glow in the dark, including watches, electronics, gadgets, and any relaxing "starry sky" lamps you leave on overnight.
Turn off the lights at night, even the dimmest nightlights.
Hang blackout curtains or close blinds to keep streetlight from entering the room.
Don't read on your tablet or smartphone before bed, and don't take them into the bedroom at all.
Try to change jobs to one where there will be no night shifts.

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

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

In the center 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 cycle of sleep and wakefulness.

So, in the daytime, 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 stress resistance. The lack of serotonin leads to the appearance of 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, malfunctions throughout the body, which are fraught with major health problems, in particular, obesity, heart attacks and breast cancer.

It is important that the production of melatonin occurs only at night and only in the dark, most actively between 12 and 2 am. And this means that healthy sleep does not threaten you if:

you go to bed after 2.00 and in the morning;
work the night shift and sleep during the day;
sleep well only on weekends.

Do not be fooled: the production of melatonin does not occur for the future, it is only enough for a day, until next sleep so you won't save your body from damage if you only sleep properly a few days a week. And daytime naps won't provide you with melatonin at all - and that's not healthy sleep at all.

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

How to get healthy sleep

Of course, the ideal healthy sleep schedule for our body is to get up at dawn and go to bed with sunset. But, unfortunately, the urban rhythm of life, an active career and technological progress have led to the fact that few of us can afford such a luxury, and the most dangerous thing is that we are almost constantly exposed to artificial light. And it 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 a healthy sleep in the dark, you will have to make some changes in your lifestyle, namely:

Remove all lamps and gadgets from the bedroom that can 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 and nightlights. If the nightlights are on extreme case in the corridor - tightly close the door to the bedroom so that the light does not penetrate 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, do not watch TV and do not read from a tablet or smartphone.

If things keep getting in the way, sleep with a tight eye patch. Sleep in the dark is determined precisely by the signals that the retina sends to the brain, so if you can’t achieve complete darkness, you can try to fool the pineal gland a little. But this does not mean that deception will succeed if you sleep in a bandage in the morning or afternoon - here the body will determine the catch at the level of biorhythms.

It is in order not to disturb these biorhythms that you need not only to remember about healthy sleep in the dark, but also about daytime serotonin, without which you will not get melatonin even during a long night's sleep. Therefore, be sure to be more often on the street in order to be under the influence of sunlight, and not artificial light, during the day.

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

Eliminate the use of alcohol, nicotine and coffee - they reduce the production of melatonin.

Introduce foods that contain the amino acid tryptophan into your diet. 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 meats.

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

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

To understand why light at night is so detrimental to health, you can turn to history. Until artificial sources of illumination filled the life of a person, he had only two "lamps": during the day - the sun, at night - the stars and the moon, and, perhaps, the light from the fire.

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

melatonin and cortisol

The production of melatonin is the key to understanding why artificial lighting is so bad for us. This hormone is produced in the pineal gland only under conditions of absolute darkness and is responsible for the sleep-wake cycle. Melatonin lowers blood pressure, body temperature and blood glucose levels, that is, it does everything to provide the body with restful, deep sleep.

In the human brain there is a part that is responsible for the biological clock - the suprachiasmatic nucleus in the hypothalamus. This is a group of cells that reacts to darkness and light and signals to the brain 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 rises, regulating energy levels.

All these processes are natural, but artificial lighting at night knocks them down. The body reacts to light and raises cortisol levels at night, making it harder for a person to fall asleep. In addition, high levels of the “stress” hormone reduce 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 disturbed.

However, the level of hormones is regulated not only by the amount of light at the moment, but also by how much light you received before.

light before bed

The danger of cancer

Unfortunately, the disruption of hormone production provokes not only poor sleep, but also more serious consequences, such as cancer. Over the course of 10 years, a study was conducted that proved that sleeping in the light increases the risk of getting cancer.

Based on the data of these studies, we can say that sleeping in the dark is the prevention of cancer and one can only sympathize with people working the night shift.

Dim light, blue light, depression and immunity

That is, if you have a backlit digital clock or other luminous devices in your bedroom that work all night, there is a serious reason to think about whether you really need them. And that's not to mention the constant light from the street lighting, which penetrates your window when there are no thick curtains.

And more health problems

What to do?

Summarizing all of the above, we can derive several rules:

Remove anything from your bedroom that can glow in the dark, including watches, electronics, gadgets, and any relaxing "starry sky" lamps you leave on overnight.
Turn off the lights at night, even the dimmest nightlights.
Hang blackout curtains or close blinds to keep streetlight from entering the room.
Don't read on your tablet or smartphone before bed, and don't take them into the bedroom at all.
Try to change jobs to one where there will be no night shifts.

Since childhood, you have probably heard that it is harmful to sleep in the light. But little ones are often afraid of the dark, and adults make concessions, trying not to provoke evening scandals, and leave the nightlight on. True, caring parents always turn it off when the child falls asleep. But the habit is not so easy to break. So it turns out that, having already become adults, some people leave a dim light on all night. What is fraught with such a habit and why you need to sleep in the dark, scientists tried to find out.

What happens in the dark

Since man does not belong to nocturnal mammals, nature has provided that he should sleep in the dark, and in the light of the day - be awake and lead active image life. To do this, our body has a built-in biological clock that measures daily rhythms. Moreover, they work properly even in complete darkness, which is confirmed by repeated experiments.

Placed in a completely dark room, a person still goes to bed at about the same time as before, when the external lighting naturally changed. If the light is constantly on, it is more difficult for him to fall asleep, but he still wants to sleep at regular intervals.

Such alternations scientists called circadian rhythms. With a sharp change in time zones, the internal settings go astray, and within certain period the person feels intense discomfort.

epiphysis

Looking for a regulator of this process, scientists discovered a small gland located in the back of the head - the pineal gland. By producing certain hormones and sending them to the blood, the pineal gland stimulates increased activity or drowsiness of a person. During the day, it increases the concentration of serotonin in the blood, and at nightfall it begins to actively produce melatonin, called the sleep hormone.

When the concentration of melatonin in the blood reaches a certain level, and this usually happens around 22-23 hours, a person shows signs of drowsiness: yawns, rubs his eyes, becomes inhibited.

If you go to bed from 22 to 24 hours, then the process of falling asleep proceeds easily and quickly, and then the person sleeps peacefully all night. By 4-5 o'clock in the morning, the production of melatonin is completed, serotonin enters the blood again, preparing us for an early and vigorous awakening.

Melatonin for sleep and more

Interested in what the hormone melatonin is and what its reduced concentration is fraught with, scientists conducted a number of studies, the results of which turned out to be extremely interesting.

It turned out that melatonin not only promotes fast falling asleep, but also affects other vital processes occurring in the body.

Prevention of depression

A lack of melatonin can provoke states close to depressive states. This was shown by experiments conducted on animals that were constantly illuminated at night.

The test hamsters became lethargic, they lost their appetite, they were even no longer interested in their favorite treats. You will say that a person is not a hamster, but people who regularly sleep in the light complain of very similar symptoms.

Slow down aging

Second important function melatonin - neutralization of free radicals that are built into healthy cells and cause their premature destruction. Produced by located in cranium gland, melatonin primarily protects against the destruction of brain cells, preserving our memory and clarity of mind.

Now it becomes clear why children who slept all the time in the light, showed the worst results in school.

Acceleration of metabolism

Another experiment showed that the test animal, which sleeps with a constantly burning light bulb (and even in dim light!), quickly gains excess weight on the same diet, which previously did not give an increase.

The lack of melatonin leads to a slowdown in metabolic processes. And given that chronic lack of sleep constantly accompanied by mild apathy and unwillingness to move a lot, a person the process is underway even faster.

Minimum light

Sleeping with light is harmful! It leads to obesity psychosomatic diseases and insomnia. Moreover, the level of lighting practically does not play a role. In order for melatonin to be produced in sufficient quantities, it is necessary to sleep in complete darkness. Even street lighting penetrating through the curtains or the glow from an electronic clock is enough to significantly reduce its production, and therefore worsen the quality of sleep.

By the way, along the way, scientists discovered another interesting connection. depressive state, including those caused poor quality sleep due to the presence of lighting in the room, is directly related to a sharp decrease immune protection organism. It is no wonder that those who sleep in the light are more likely to get colds and viral diseases.

How to save melatonin

Why you need to sleep in the dark, it became clear in the course of experiments that discovered important role melatonin in human body. But is it possible to somehow stimulate its production? What can be done to ensure that the concentration of melatonin does not decrease to a dangerous threshold?

And most importantly, remember that healthy lifestyle life is the key to a fulfilling sound sleep. Not exhausted by artificial stimulants and not poisoned by toxins and poisons, the body usually has no problems with sleep.