It is a well-known fact that everyone should sleep. But why sleep? How long does a person need to sleep a day? What benefits does sleep have to human health? But not everyone understands.

Sleep is the need to rest, check and repair the brain. The human brain has a highly developed function, but after continuous operation to a certain extent, the brain will be tired. Scientists' research proves that a person can stay awake for 3-4 days.

If you don't rest and sleep for a day and let your brain run overload, it will make your brain tired, your consciousness level will drop and your intelligence will be damaged. Therefore, it is very necessary to repair the "maintenance mechanism" of the brain.

Sleep is not only to rest the body, but also to rest the brain, because no matter how quiet, as long as the consciousness is awake, the fatigue of the brain will not be eliminated.

People must "eat" for personal survival; For the survival of species, it is necessary to "reproduce"; In order to let the brain rest, it is necessary to "sleep". Sleep is the "patron saint" to maintain life.

Second, the physiological process of sleep

EEG and physiological function tests show that sleep has two different phases: one is the slow wave in EEG, which is called slow wave sleep; Second, there are fast waves in EEG, which is called fast wave sleep. Sleep begins with slow-wave sleep, lasts about 80~ 120 minutes, and then turns to fast-wave sleep. Fast-wave sleep lasts about 30 minutes, then turns to slow-wave sleep, and so on. Therefore, when sleeping, the brain doesn't get a rest. It works day and night like the heart and lungs, but it just changes a way of working and carries out "reorganization" and "correction".

Modern science has found that people's sleep is caused by the decrease of incoming information from the brain and the active excitement of the sleep center. The two sleep centers (fast wave and slow wave) are like a "biological clock", which is excited alternately at regular intervals.

During sleep, only people's consciousness level is low, and most physiological activities and reactions of the body have undergone a series of changes, showing an inert state: heart rate slows down, breathing rhythm deepens, blood pressure drops, and basal metabolic rate decreases. Generally reduce 10%~ 15%. However, during sleep, the activity of parasympathetic nervous system increases. Such as pupil contraction, increased gastric juice secretion, hyperhidrosis, etc. At the same time, during sleep, anabolism exceeds catabolism, and a variety of biological substances are secreted vigorously, such as growth hormone.

What effects does sleep have on human health?

The role of sleep is mainly manifested in the following aspects:

1. repair the brain and restore the spirit. The oxygen consumption of the brain is greatly reduced during sleep, which is beneficial to the energy storage of brain cells. In addition, the brain can also repair and maintain some important nerve cell groups during sleep to avoid failure and destruction.

2. Eliminate fatigue and restore physical strength. When sleeping, the body temperature, heart rate and blood pressure drop, and the respiratory frequency decreases, which reduces the basal metabolic rate, thus restoring physical strength; During sleep, the anabolism of energy substances in the body exceeds catabolism, so that the energy consumed by tissues is supplemented.

3. Improve immunity and prevent diseases and diseases. Sleep can improve the body's ability to produce antibodies, thus enhancing the body's resistance; Sleep accelerates the self-healing of tissues and organs, and modern medicine has regarded sleep as one of the means of rehabilitation after illness.

4. Promote development and improve intelligence. People's sleep is carried out in the constant alternation of slow-wave sleep and fast-wave sleep. Growth hormone is secreted most in the third and fourth stages of slow-wave sleep, so adequate sleep can promote human growth and development.

5. Delaying aging and promoting longevity is first of all the decrease of brain cells, and the way to delay the decrease of brain cells is adequate and effective sleep. Therefore, a good and normal sleep is one of the important conditions for a long and healthy life.

6. Accelerate skin metabolism. During sleep, skin metabolism is active, blood vessels are more open, providing more nutrition and oxygen to the skin and taking away various toxins and metabolites; Growth hormone secretion increases during sleep, promotes skin regeneration and repair, and keeps skin tender and elastic; The activity of antioxidant enzymes in human body increases during sleep, which can effectively remove free radicals in the body and keep the skin young; After enough sleep, a good mental state is an important factor in beauty.

Fourth, why do people suffer from insomnia?

Insomnia is caused by various reasons, such as difficulty in falling asleep, lack of sleep, early awakening, lack of sleep and so on.

There are many reasons for insomnia. According to each person's age, gender, physical condition, surrounding environment and psychological barriers, it can be divided into:

1. Physiological factors, such as changing the original motivation stereotype, such as business trip, night shift, unfamiliar sleeping environment, or drinking strong tea, coffee and wine before going to bed, make the brain excited. Or the ambient sound, light stimulation is too strong, the temperature is too hot and too cold, etc. Insomnia caused by physiological factors is temporary and can be prevented by changing conditions without treatment.

2. Psychological factors such as emotional anxiety, tension, fear, interpersonal conflict, difficulties in life or work, unstable life, working overtime day and night. Insomnia can only disappear if the psychological factors leading to insomnia are removed.

3. Pathological factors such as schizophrenia, anxiety, depression, cerebral arteriosclerosis, neurasthenia, liver disease, nephropathy, asthma, itching, dysuria, frequent urination, vomiting and diarrhea. Insomnia can only disappear after the treatment of the above diseases.

4. Taking drugs that are exciting to the central nervous system and other drug factors. In addition, coffee can also cause insomnia.

Don't take sleeping pills often to solve insomnia. Sleeping pills are not good for the "reorganization", "reorganization" and recovery of the brain, which not only affects the ability of learning and memory, but also has other side effects. Excessive use may even lead to death.

Fifth, the correct way to sleep.

1. Eat less dinner, don't be too full, and don't eat snacks before going to bed.

2. Exercise properly after meals and don't go to bed immediately.

3. Keep the environment quiet and peaceful when you fall asleep.

4. Sleep on the right side, and don't lie flat or supine.

5. The height and hardness of the pillow should be moderate. The height should be big and the hardness should be comfortable.

6. Sleep in the wind, but don't sleep with your head covered.

7. In order to prevent lumbar spondylosis, wooden beds should be advocated.