For example, I was sitting at my desk writing the article you were reading, but I closed my eyes, put my arms on the arm of the chair, my palm facing up, and my left hand was holding a big bell.

Sleeping can also be part of the work. For example, I was sitting at my desk writing the article you were reading, but I closed my eyes, put my arms on the arm of the chair, my palm facing up, and my left hand was holding a big bell (why will be explained later).

This sleeping position is really indecent, but I am sleeping in the name of science and efficiency. The greatest thinkers in history all believe that naps are good for health. And judging from the latest research, their views seem to be correct.

In recent years, scientists have discovered that just a short nap can improve many functions of the body, including memory, creativity, cardiovascular health and immunity. Naps can also restore people's brain and physical strength. Some people even regard naps as a public health measure that needs to be promoted urgently - especially today when everyone is exhausted.

As we all know, most adults need 7 to 9 hours of sleep a day; we also know that many people do not meet this standard. The habit of using electronic products, work pressure, dependence on caffeine , and night shifts are all reasons for lack of sleep.

According to a report released by an online survey and data analysis company in early 2022, one in eight people sleeps less than 6 hours, and one in four people need to take sleeping pills to fall asleep.

Long-term lack of sleep increases the risk of hypertension and heart disease, and also leads to decreased immune function and obesity. No wonder insomnia has become a hot topic for scientists.

Recently, scientists from the Institute of Brain Science in Paris verified a theory proposed by Edison : fragmented naps can activate brain efficacy, increase alertness, and strongly stimulate creativity - but they must be a very short nap, otherwise you will enter deep sleep and wake up with poor spirits.

Go back to the sleep experiment I did at the beginning of the article. As I held the bell and felt my eyelids start to fight, my thoughts and consciousness gradually blurred. Finally, my eyes went dark and I lost consciousness. At this time, the bell fell from my hand, which scared me to wake up. This feeling is strange, but seems useful. I immediately felt that my brain was clearer than before I fell asleep, and my writing thoughts became smoother.

What changes will happen to the human body when taking a nap?

Napping is roughly the same as sleeping at night. It usually goes through a cycle of falling asleep and waking up, but the time is relatively short. First of all, after sleepiness comes, you will fall into a semi-sleep state, which usually lasts for about 5 minutes. Then, as your consciousness disappears, you will enter the second stage, when your breathing slows down, your muscles relax, and your core body temperature drops. Brain activity is also weakened.

The second stage of sleep is a critical period for improving alertness and thinking ability. The second stage lasts about 10 to 25 minutes, and then, deep sleep begins (the third stage of sleep). The main change during this period is that the brain produces characteristic Delta brain waves (δ waves). Scientists believe that this 40-minute sleep phase is a critical period for the human body to rest: the immune system and various body functions begin to recover themselves, and memory is consolidated during this period.

The third stage is followed by the fourth stage, also known as the rapid eye movement stage. At this time, 60 to 90 minutes have passed since I fell asleep, the dream has become vivid and the muscles in my body are relaxed. But the eyes are the exception, and the eyes move quickly under the eyelids. The rapid eye movement stage can enhance creativity and promote the processing and semantic correlation of sensory information. Deep sleep (the third stage) is a period of learning, encoding and memory of new information, but the integration of information into the semantic network occurs in the rapid eye movement stage.

Can a nap make up for insufficient sleep?

Inspiring creativity is certainly not the reason most people take a nap. Many times, people are just tired. But can naps really make up for the lack of sleep caused by staying up late and insomnia to a certain extent? The advantage of taking a nap is that it also has some functions of sleeping at night and uses it less time. Each complete sleep cycle is about 90 minutes, during which time the human body will go through all four stages, producing corresponding physiological effects.

If you wake up in the second stage of sleep, you will likely feel refreshed, but only deeper sleep than the second stage can restore human functions on a physiological level. Deep sleep has an important impact on the recovery of body functions, blood pressure levels and other aspects of the human body. There is a channel in the brain called the lymphoid system. During deep sleep, the lymphoid system opens to excrete metabolic waste and chemicals accumulated when the brain wakes up.

It should be noted that the nap time should not be too long or too late, otherwise it will affect the sleep at night.

Nap enhances creativity?

If you believe in Edison and Einstein , then naps will really make people more creative. Many scientists and artists rely on naps to keep their minds quick or seek inspiration. Modern science has confirmed many benefits of napping: some papers point out that napping can improve people's cognitive abilities, including creativity, learning ability, etc.

Inspired by Edison's concept of " microsleep ", Delfina Udiert of the French Institute of Brain Science conducted a confirmatory study. She showed the volunteers a math problem, and if the other party couldn't solve it, Udiet would let them lean on the chair and rest. After a short break, those volunteers who entered the first stage of sleep—a vague consciousness but did not really fall asleep—have three times more likely to solve math problems than those who did not rest. It looks like the brain may have turned on the creative switch while napping.

Other cognitive abilities seem to be related to other stages of sleep. For example, attention and alertness are related to the second stage.

We also need deep sleep (the third stage) to improve our memory. Effective deep sleep needs to last at least 40 minutes, but sleeping too deep will increase the risk of sleep laziness, making people feel drowsy after waking up.

Naps can also regulate mood (parents with children may be aware of this). Naps can help us digest and control negative emotions. So if you encounter something that annoys you, maybe taking a nap before dealing with it is a good idea.

Napping and natural evolution are related to

All human rhythmic behaviors, including sleep, are the result of evolution because we live on a planet where we can see the sun and the moon. Not just us, other animals, plants and even bacteria have cycles of alternating rest and activity. Many causes humans need to sleep, some of which are related to evolution. Including humans, dozing off seems to be more in line with the laws of nature.

culture also has an impact on naps. Studies have shown that students who do not have lunch break are more likely to have learning problems. In a society with a nap culture, people who like naps also seem to perform better in their daily lives.

Why is napping healthier?

The benefits of sleep for the body and mind are obvious, and its importance cannot be overstated. Poor sleep quality has adverse effects on the human body, and the consequences will continue to accumulate. If you don’t sleep well for a few days, your cognitive ability will be damaged, resulting in a decrease in attention, memory, and thinking ability. If you have poor sleep for a long time, it will not only damage cognitive ability, but also affect your health and cause problems in metabolism, endocrine, immunity, etc.

There are often studies linking poor sleep quality to the risk of heart disease, obesity and other diseases. Deficiency of sleep can also increase the risk of chronic diseases such as hypertension, diabetes and . There are even large-scale analytical studies that show that lack of sleep is associated with premature death.

Scientists believe that napping habits may reduce these risks to some extent. Physiologically, naps have as many benefits as sleeping all night. There is growing evidence that naps can not only improve alertness and cognitive ability, but also reduce the body's stress response and correct immune disorders caused by insufficient sleep to a certain extent.

So, when you feel sleepy, taking a nap is very useful - taking a nap is not only about closing your eyes, but also completely restarting your body.

It's worse after taking a nap?

Some people don’t feel refreshed after waking up after taking a nap, but instead feel weak, unable to concentrate, and unable to perform cognitive functions normally. This state between sleep and wake up is called "sleep laziness". If you take a nap and feel this way when you wake up, there may be two reasons: either the nap time is wrong or it has something to do with genes.

It is very difficult for most people to wake up from the third stage of sleep. This may be related to brain activity in the third stage, or it may be due to slowing blood flow throughout the body. The way to deal with this is to set an alarm clock before bed and let it wake you up in the second phase rather than the third phase - this is about 20 to 30 minutes after you go to bed. Although this reduces sleep time, you will feel energetic when you wake up.

Another reason is that you may not be suitable for naps. Scientists have tried to train people who don’t like naps so that they can get the benefits of naps, but found that during a month of training, naps training did not bring any changes, their cognitive abilities did not improve, and their sleep patterns did not change. Therefore, there may be genetic differences between those who love to take naps and those who do not. But in this regard, scientists need more research.

Naking should not be too long

Although there are many benefits to rest in a planned manner, some studies have shown that naps are not always good for health, especially for the elderly.

In 2020, a study analyzed data from 20 papers and found that compared with those who did not take naps, people who often had more than one hour of death had a 30% higher risk of death and 34% higher risk of cardiovascular disease.

One explanation for this is that taking a nap for too long will cause the body to have an inflammatory reaction and increase the risk of heart disease. However, controlling the nap time to 30-45 minutes will have a protective effect on the body.

At the same time, researchers at UC San Francisco found that excessive naps are related to neurodegenerative changes in the elderly. They found that those elderly people who took a nap for more than one hour a day had a 40% increase in the risk of developing Alzheimer's disease , but the causality is not yet clear.