Introduction: Uncle Lu is 60 years old this year, and his retirement life is very regular, with regular and quantitative meals every day, early to bed and early to get up, and good sleep habits.
In addition, he has a special habit of taking a nap at noon every day, usually an hour or two, which he thinks will replenish his energy and better cope with his afternoon life.
In the evening, he and his wife walked and exercised downstairs in the community, enjoying the fresh air and quiet time in the evening.
However, during this year's check-up, he was surprised and worried to learn that his blood pressure and blood lipid levels were higher than normal.
When he searched for relevant information on the Internet, he found that many articles discussed the effects of napping on blood pressure and blood lipids, and some people even thought that napping might cause blood pressure and blood lipids to rise, and then affect life expectancy, which made him feel very panicked and confused.
Could it be that my abnormal health indicators are caused by taking a nap every day?Uncle Lu began to wonder if his lifestyle was really healthy. 
In June 2023, a striking study was published in the well-known academic journal Sleep Health, which revealed a causal relationship between habitual napping and an increase in total brain volume.
The study was a large-scale survey involving 37More than 80,000 subjects, who were divided into three groups according to their napping frequency, with 38 percent in the sometimes napping group, 5 percent in the frequent napping group, and 57 percent in the never napping group.
The researchers conducted an in-depth analysis of 92 independent genetic variants associated with napping to assess the causal relationship between napping and cognitive function and brain volume, and this study used advanced statistical methods and data analysis techniques to comprehensively assess the subjects' napping habits and brain volume.
The results of the study were shocking: subjects who habitually napped increased their total brain volume by 1580cm, this difference in brain volume, is equivalent to a slowdown in brain volume aging by 26 to 65 years!
This finding suggests that habitual napping can promote brain development and keep the brain healthy, which is especially important for older adults, in addition to revealing 5 benefits of proper napping.
Rejuvenate
After a morning of work or study, the body and brain may feel tired, a proper nap can restore energy and make you more focused and productive in the afternoon work or study.
Boosts immunity
Napping helps to strengthen the immune system and reduce the risk of infection and disease, lack of sleep can lead to a decrease in immune system function, and proper napping can promote the regeneration and activity of immune cells.
Improves cardiovascular health
Napping can improve cardiovascular health by lowering blood pressure, heart rate, and cholesterol levels, and sleep deprivation can increase the risk of cardiovascular disease, which can be prevented by proper napping.
Enhances memory and learning
Napping can improve memory and learning. During sleep, the brain processes and processes new information to consolidate memories. A proper nap can help you improve your memory when learning something new or preparing for exams.
Promotes good health
A proper nap can promote good health. Lack of sleep can lead to a decline in physical functioning, and a proper nap can promote the normal functioning of the body and improve the overall health level of the body.
The impact of napping on longevity and health has been a topic of concern, and past studies have shown that excessive napping can have negative health effects and may even affect longevity.
Researchers from the University of California conducted a 1,065-year follow-up survey of 1,065 middle-aged and older adults for 14 years, and they recorded the nap duration of these people and analyzed the link between nap length and Alzheimer's disease.
The results of the study showed a "potential two-way relationship" between Alzheimer's disease and nap duration, with people who took naps longer than one hour per day had an increased risk of developing Alzheimer's disease by about 40 percent compared to those who took naps for less than one hour per day.
At the same time, the average nap time of people who already have Alzheimer's disease is 3 times higher than that of the general population, and the researchers analyzed that during sleep, the capillaries of brain tissue will be closed under the regulation of the central nervous system of the brain.
The longer you sleep and the longer you turn off, the body's metabolism will also slow down, which may affect the basic functions of the brain, thus laying the foundation for the occurrence of Alzheimer's disease.
In addition, a study presented at the 2020 European Congress of Cardiology found that napping longer than 1 hour was associated with a 30% increased overall risk of death and a 35% increased risk of cardiovascular disease, all of which suggest a link between nap time and physical disease.
Although these findings are worrying, a proper nap is still beneficial to the body, and a proper nap can relax the muscles and brain of the human body, especially for people who engage in a lot of physical and mental activities, it is necessary to restore their physical strength, so napping is still necessary, but the time must be controlled.
For middle-aged and elderly people who take frequent lunch breaks, doctors recommend following the three "don't" principles, which will allow you to take a nap more healthily.
In the busy rhythm of life, napping is undoubtedly a good way to restore energy and improve work efficiency, however, like a double-edged sword, the impact of napping time on health cannot be ignored.
Researchers from the University of California in the United States, in a 14-year follow-up study of 1,065 older adults, who detected sleep through a wristwatch, found that subjects who took at least one nap a day for more than 1 hour increased the risk of dementia by 40% compared to those who took a nap of less than one hour a day, a finding that undoubtedly reminds us that napping longer is not always better. 
So, what is the best nap time?Researchers from the University of Huelva in Spain have published new research in the European Society of Cardiology. The study included more than 20,000 participants and was followed for up to 14 years.
The results showed that prolonged naps were associated with an increased risk of atrial fibrillation. Specifically, people who nap too long have a 90% increased risk of atrial fibrillation;In contrast, those who took naps for less than 15 minutes had a 42% lower risk of atrial fibrillation, while those who took naps for 15 to 30 minutes had a 56% lower risk of atrial fibrillation.
Through these studies, we can clearly see that the optimal nap time should be controlled at 15 to 30 minutes, which is effective in relieving fatigue and avoiding the negative effects of sleeping too long.
Don't sleep on your stomach
Sleeping on your stomach is a poor sleeping posture because it will put your neck in a forward bending state, and maintaining this position for a long time can easily lead to stiff and painful neck, and even cause cervical spine disease.
Especially for teenagers, they are in a critical period of physical development, and if they often sleep on their stomachs, it may lead to problems such as scoliosis, deformity, and then affect the normal development of the body.
In addition to the effects on the neck and spine, sleeping on your stomach can also have adverse effects on the eyes and stomach, and people tend to feel swollen eyes, blurred vision, and even dizziness after waking up due to the compression of the eyeballs.
Don't take a nap too late
Napping is a short form of rest that can help us regain energy and improve productivity, however, if the nap is too long or too late, it can affect the quality of sleep at night.
This is because the human body has a natural sleep rhythm, and if you nap too long or too late, it will interfere with this rhythm, making it difficult to fall asleep at night or sleep poorly.
In order to maintain a good quality of sleep, it is recommended to take a nap in the early afternoon, preferably before 3 pm, so as to avoid disturbing the sleep rhythm at night and ensure the quality of sleep at night.
Don't take a nap immediately after lunch
Taking a nap immediately after lunch is an unhealthy lifestyle habit as it can lead to stomach upset and other health problems, and when you have just finished lunch, the stomach needs a lot of blood to help digest food.
If you lie down and take a nap right away, blood will concentrate in your stomach and other parts of your body won't get enough blood**, which can cause you to feel dizzy, fatigued, and even faint.
Secondly, because the stomach needs a lot of blood to help digest food, if you lie down and take a nap immediately, the stomach will be compressed, causing food to flow backwards into the esophagus, causing gastroesophageal reflux disease, which can cause you to experience chest pain, coughing, and even difficulty breathing.
Patients with sleep disorders
People with sleep disorders often sleep poorly at night and get tired easily during the day. If they take a nap during the day, it can affect the quality of sleep at night, leading to a vicious cycle.
People with dyslipidemia or high blood viscosity
After lunch, the body needs to digest the food, and blood circulation will speed up, which may cause symptoms in people with dyslipidemia or high blood viscosity. Therefore, these people should try to avoid napping to reduce physical discomfort.
People with low blood pressure
During napping, blood pressure decreases, which is beneficial for people with normal blood pressure, however, for people with low blood pressure, napping may aggravate their symptoms such as dizziness, fatigue, etc.
Drink a glass of warm water
After a nap, the body needs to replenish water, drinking a glass of warm water can boost the body's metabolism, help the body eliminate toxins, and at the same time can relieve fatigue and refresh the mind.
Do simple exercises
After a nap, the body needs activities to promote blood circulation, you can do some simple exercises, such as walking, jogging, yoga, etc., these exercises can soothe the body, relax the mind, and at the same time can strengthen the body's immunity.