How long should proper sleep last?

Modern life is quite intense, and often a person sacrifices sleep in order to have time to finish all the things. Unfortunately, this is very harmful to health, because sleep is as important for a person as proper nutrition and physical activity. Even a slight lack of it can negatively affect mood, energy, mental sharpness and ability to cope with stress. But how long should proper sleep last: 6, 7 or 9 hours?

Sleep is much more than just resting time for body and mind. In fact, while we sleep, our body is working hard. During this time, muscles that have received microdamages during the day are restored, the immune system is strengthened, and metabolism is regulated. In addition, night rest is extremely important for regulating the emotional state of a person. Studies show that lack of sleep makes people up to 60% more emotional and prone to irritability. A study published in December 2015 in the journal Trends in Neurosciences proves the relationship between sleep quality and the ability to keep busy with one task. In order to focus on completing a task, the brain must “turn off” certain functions responsible for collecting information from the outside world.

Myths and facts about sleep

Myth: If you sleep an hour less, it will not affect the activity during the day.

Fact: a person may not feel very sleepy, but the lack of a night’s rest even at 1 o’clock can affect the adequacy of thinking and the speed of reaction. In addition, even this seemingly minor lack of sleep can compromise cardiovascular health, energy, and ability to fight infections.

Myth: The human body adapts quickly to different sleep schedules.

Fact: in fact, the body is able to “rebuild” its biological clock for a maximum of 1-2 hours a day without consequences. This means that after moving to another time zone or after switching to a night shift, it may take at least a week for the body to adjust to a new life schedule.

Myth: A longer night’s sleep can relieve excessive daytime fatigue.

Fact: It is important to understand that the amount and quality of sleep are two different things. Some people can sleep for 9-10 hours, but do not feel rested after waking up just because the quality of their rest wants to be better.

Myth: On weekends, you can get enough sleep for the whole week.

Fact: it is impossible to completely make up for the lack of sleep accumulated during the working week. Such a practice can only negatively affect the rest-wake cycle, due to which on Sunday a person can remain active until late at night, but it will be very difficult for him to wake up on Monday morning.

How many hours do you need to sleep

To begin with, it must be understood that there is a difference between how much a person can sleep and the amount of sleep that is actually necessary for the optimal functioning of the body. According to experts, on average, adults sleep for 7-6 hours. At first glance, it may seem that these are quite good indicators. In fact, this is a typical example of chronic sleep deprivation.

Most healthy adults need 7 to 9 hours of sleep per night. For children and adolescents, this figure is slightly higher. Despite the fact that older people should also not have less than 7 hours of rest, many in old age suffer from insomnia. In this case, you should at least partially compensate for the lack of night rest with daytime sleep.

Interestingly, researchers at the University of California, San Francisco have found that some people have a gene that allows them to sleep 6 hours a night and still get great sleep. However, this gene is found in only 3% of the world’s population.

Signs of lack of sleep

The best way to understand if you are getting enough sleep at night is to critically assess your state of mind during the day. Although people who are accustomed to constantly “saving” on their vacation may no longer remember how it is to be truly awake, to be as concentrated as possible. But there are certain signs that a person is not getting enough sleep.

You may be sleep deprived if:

• need an alarm clock to wake up on time;
• you can rearrange the alarm after the call for a few more minutes;
• difficulty waking up and getting out of bed;
• feel sluggish during the day
• you can switch off in a meeting, in class, or in an empty office;
• feel sleepy while driving a car and after eating;
• need daytime sleep, at least for a short time;
• fall asleep quickly while watching TV;
• on weekends you can sleep much longer than on weekdays;
• fall asleep within 5 minutes of going to bed.

Consequences of lack of rest

It may seem that lack of sleep is not such a serious problem, and all the consequences of lack of sleep come down solely to daytime lethargy. In fact, as scientific experiments show, the lack of a night’s rest affects a person in much the same way as alcohol abuse.

Sleep deprivation is:

• fatigue, lethargy, lack of motivation;
• bad mood, irritability, increased risk of depression;
• impaired brain activity, problems with memory, learning and concentration;
• decreased creativity and ability to quickly solve problems, difficulty in making decisions;
• inability to cope with stress and manage emotions;
• dysmotility, increased risk of accidents;
• weakening of the immune system, a tendency to frequent colds and infectious diseases;
• hallucinations and delusions are possible;
• increased risk of stroke, diabetes, hypertension, Alzheimer’s disease, certain types of cancer;
• decreased sexual desire;
• premature aging of the skin.

In addition, scientists have found a direct link between lack of sleep and weight gain. In the bodies of people suffering from lack of sleep, an increased amount of cortisol, a hormone that increases appetite, is produced.

What to do to sleep

Many experts argue that in order to wake up rested and full of energy, it may not be enough just to go to bed early. It is necessary to calculate at what time the brain enters the phase of shallow sleep – and if a person wakes up during this period, he will have no problems getting up.

It happens that a person, it would seem, fell asleep quite early in the evening, but in the morning he still feels lethargic. The reason for this may be waking up in the wrong phase of sleep. In the course of scientific observations, scientists have determined that if a person wakes up in the REM phase, then he can feel alert even after a 6-hour rest. On the other hand, sleep can last even 10 hours, but if a person is awakened in the deep sleep phase (the last 4th stage of the slow phase), then in most cases he will feel much worse than in the first example. Therefore, for a more comfortable and easy morning awakening, experts have developed a special sleep calculator. But in order to use it skillfully, you must first understand something about the phases of sleep.

What you need to know about sleep phases

During rest, our brain goes through two main phases: non-REM and REM sleep, which alternate during the night. During the slow phase, the brain gradually enters a state of deep relaxation. It is at this time that the main processes of regeneration proceed intensively in the body. For most people, non-REM sleep lasts an average of 90 minutes, after which the brain enters REM sleep. During this period, brain activity increases again, the pulse increases, and it is during this period that a person sees dreams. This phase lasts approximately 15 minutes. If at this time there is no awakening, the brain goes back into the phase of non-REM sleep. During the night, the whole cycle is repeated 4-5 times.

That is, since the slow phase is the time when the brain gradually “turns off” and goes into the state of the deepest relaxation, awakening during this period is the most difficult and unpleasant. As a rule, in order to wake a person in the stage of deep sleep, either a loud sound or shaking is required. In this case, he will need a little more time to fully awaken and restore vigor. Many after such an awakening during the day are accompanied by a feeling of fatigue, as if he had not had a night’s rest.

During REM sleep, waking up is much easier and faster, because the brain is in a state almost identical to daytime wakefulness during this stage. Waking up during this period, a person feels cheerful, fresh and ready for action. Therefore, the REM phase is considered the best time to wake up.

How to calculate the most comfortable time to wake up

Using the average data on the duration of the phases, you can create your own sleep calculator and calculate how long the rest should last in order to wake up easily in the morning.

We already know that slow wave sleep lasts approximately 90 minutes, which means that in order not to wake up during this period, the total duration of the night’s rest should be a multiple of 90 minutes (1,5 hours). That is, if a person plans to get up at 7.00 in the morning, then he should fall asleep at 23:30. The result is 450 minutes of rest, which is equal to five 90-minute cycles. But in such a calculation, one must also take into account the additional time required to fall asleep. This usually takes about 15 minutes. That is, taking into account the time to fall asleep, it is necessary to go to bed at 23:15. As a result, the duration of sleep will be 7,5 hours, which fits perfectly into the recommended norms for a healthy night’s rest.

If a person does not have time to fall asleep before 23:30 pm, but still has to get up at 7 am, then according to this theory, in order to wake up vigorous, he must lie down between 1:00 am and 2:30 am. Falling asleep at a different time will cause you to wake up in the deep phase. And what it is fraught with, you already know. Nevertheless, going to bed after 1 or even 2 am can hardly be called correct and beneficial for the body.

In addition, it should be emphasized separately that the duration of the slow phase of 90 minutes is an average, which in reality may not be suitable for everyone. There are people for whom this phase lasts 120 minutes, for others it takes only 80 minutes. Therefore, the most accurate personal calculator can only be compiled after observations: sleep 7 hours one day, 8,5 hours the other, etc. It is best to experiment with different sleep times on weekends. As a result, it will be possible to determine your own duration of the non-REM sleep phase.

There is another – more comfortable and faster – way to determine individual indicators of sleep phases. To do this, you need to remember when you went to bed. In the morning, it is important to wake up on your own – without an alarm clock or extraneous noise that interrupted your rest. After such an awakening, a person should feel alert and well rested (if everything is done correctly, then the person will wake up on his own in the REM phase). Now you need to calculate the duration of rest in minutes and divide the resulting number by 5 (so many sleep cycles are considered the most beneficial for the body). The result obtained is one cycle of your sleep. In the future, to determine the most comfortable time for awakening, this number must be multiplied by the number of required cycles.

Theoretically, using such a calculator, you can easily wake up fresh every day even after 6 hours of sleep. But in practice, this technique will work only the first few times. Then the body begins to suffer from chronic sleep deprivation. According to the observations of experts, a 6-hour night’s rest without serious damage to health can be afforded no more than 1 time per week. The rest of the time, you need to invest in a healthier framework of 7 to 9 hours of rest.

The transition to a healthier lifestyle and the right amount of sleep should begin with an assessment of personal habits and needs. Analyze how you respond to different sleep durations. This will help you choose the length of night rest that is most suitable for you. But at the same time, do not forget about the recommendations of experts about how long a proper rest should last.