March 23, Beijing, China, March 21 is World Sleep Day. The theme of this year's Sleep Day is "Good Sleep, Healthy Together".

  "World Sleep Day" was initiated by the International Mental Health and Neuroscience Foundation in 2001, and in 2003, the China Sleep Research Association officially introduced it into China.

For the "sleep" that happens every day, many people have a lot of confusion: what kind of sleep can be called "good"?

Is it reliable to use a smart watch to detect sleep quality?

Is dreaming good for sleep?

Does sleep help you gain weight or lose weight?

  long sleep, not necessarily good sleep

  Adequate sleep, balanced sleep and proper exercise are the three health standards recognized by the international community.

When it comes to "sufficient sleep", many people think of length, but it's not the standard for good sleep.

  Xie Liang, an attending physician in the Department of Neurology of the Second Affiliated Hospital of Nanchang University and a member of the Sleep Group of the Neurology Branch of the Chinese Medical Doctor Association, said that good sleep is the process of recharging the human body. The energy to deal with a day's work, study and life, this is good sleep.

  Good sleep can not only help the human body recover physical strength, enhance resistance, promote human metabolism, but also be good for mental health.

  Whether the quality of sleep is good depends on the deep sleep period

  What kind of sleep can help the body effectively restore energy?

This is about deep sleep.

  Sleep is divided into non-rapid eye movement sleep (NREM sleep) and rapid eye movement sleep (REM sleep). NREM sleep is further divided into N1, N2, and N3 sleep.

When the human body enters the sleep state, it usually transitions to N1 and N2 sleep, then enters N3 sleep, and finally enters REM sleep.

This cycle, 4-6 times a night, is a complete sleep cycle.

  N1 and N2 sleep are light sleep, while N3 is deep sleep.

Although the deep sleep period only accounts for 15%-25% of the entire sleep time, the recovery efficiency of the human body at this time is very high.

Therefore, if the proportion of deep sleep is long, it means that the quality of sleep is good.

  Watch detect deep sleep?


  Deep sleep is called "golden sleep", so it is longed by many people.

In order to pursue deep sleep, many people also try to use tools such as smart watches for sleep detection.

However, Xie Liang reminded that the watches on the market that claim to be able to judge whether the human body is in light sleep or deep sleep are inaccurate.

  Light sleep and deep sleep are divided based on brain waves.

If your brainwave frequency is fast, you may be in light sleep; if your brainwave frequency is slow and deep, you may be in deep sleep.

However, the watch is worn on the wrist and does not come into contact with the scalp, so brain waves cannot be measured, and the sleep state can only be judged based on the wearer's movement range, which is at best a means of assisting judgment.

If you want to get an accurate judgment, you must go to a professional medical institution for brain wave monitoring.

  Too many nightmares?

may affect health

  Dreaming, all occurs during rapid eye movement (REM).

During this period, not only will the eyeballs rumble, but the brain will also dream.

If a person wakes up during REM, the person is in all likelihood dreaming and can clearly recall the content of the dream.

But if a person wakes up from the NREM period, they often don't remember what dream they just had.

  If you have too many dreams at night, it means that the rapid eye movement period accounts for an excessive proportion of the entire sleep cycle.

No matter which sleep period, there is a reasonable proportion range, too long or too short is an unhealthy sleep state.

  In Xie Liang's view, dreams are only divided into ordinary dreams and nightmares.

If there are too many nightmares, people will wake up frequently from dreams, which will affect the quality of sleep, and then affect their work and study during the day.

But from another perspective, dreaming is also a learning process.

Dreams are often the repetition of work and study activities during the day, and foreign studies have shown that this is helpful for people's memory.

  Lose weight by sleeping?


  Sleeping can really help you lose weight, but not because you don't have time to eat, but because sleep affects the endocrine system.

  Xie Liang explained that 11:00 pm to 2:00 am is the most critical period for human body repair, and the endocrine system will enter a good working state at this time.

If you do not sleep at this time, over time, the endocrine system will be disturbed, which may cause excessive hormone secretion, increase appetite during the day, and eventually lead to weight gain; at the same time, the metabolic rate may also be slowed down, which will also lead to weight gain.

  Therefore, sleeping more and sleeping well will help you lose weight, but sleeping less will make you fatter. This is the truth of "overworked fat".

  Reporter: Yang Yang