2024-04-27 00:15:36
Joo Eun-yeon, professor of neurology at Samsung Seoul Hospital
“You need to develop sleeping habits to get a good night’s sleep.”
“When I sleep through the weekend to make up for lack of sleep.
Even if you wake up later, you still have to stick to your bedtime.”
There is a saying that sleep is the best medicine. It’s not wrong. If you do not get a good night’s sleep, your chances of developing various chronic diseases increase. There are also research results showing that life expectancy is shortened.
However, there are many modern people who want to sleep well but cannot. Even if it is not a sleep disorder, if this condition is left untreated for a long time, it can have a long-term negative impact on health. Joo Eun-yeon, a sleep expert and professor of neurology at Samsung Seoul Hospital, said, “Creating healthy sleep habits is more important than anything else.”
●“Understand your biological clock”
Professor Joo goes to bed at 9 PM every day. Sleep time is about 7 and a half hours. I wake up at 4:30 am and start my day. Professor Joo said he was a ‘morning person’. In fact, I’m so exhausted at night that I can’t do anything. For this reason, I finish all my work before evening. If you want to sleep well at night, the first thing you need to consider is your ‘biological clock’. Based on bedtime, people are roughly divided into morning type, evening type, and intermediate type. Medium type if your bedtime is from 11:30 PM to 12:30 PM. If you go to bed before that, you are a morning type, and if you go to bed well past midnight, you are an evening type. Professor Joo said, “This is a concept first proposed by a German biologist, and it is also being used in the field of sleep medicine.”
In general, the intermediate type is the most common. Recently, the proportion of evening meals has been increasing due to the use of smartphones and computer devices. Professor Joo estimated that the proportion of evening types has recently increased to about 40%.
If you are an evening type, going to bed at 9 or 10 PM is impossible. I have no choice but to go to bed after midnight. Additionally, evening types have a strong tendency to postpone bedtime. At first, I went to bed around midnight, but later I put it off until 1 or 2 a.m., and my wake-up time was delayed accordingly. In this case, as the biological rhythm becomes unstable, sleep disorders such as insomnia are likely to occur. Therefore, if you are an evening type, you should try to stick to your waking up time more than anything else.
If you’re a morning person, it’s not easy to last until midnight. For this reason, it is best to complete all work during the week if possible. If you reduce your sleep while doing other things, you are more likely to develop daytime drowsiness or nighttime insomnia. Fatigue becomes worse, and work and study abilities are greatly reduced. There are also red flags for mental health.
●“Go to bed at the same time every day.”
According to Professor Joo, healthy sleep can be achieved when △sufficient sleep time △good sleep quality △and the cycle of sleeping and waking up is even. To obtain these three things, you must create a regular bed habit.
First, you must set a time to stay in bed and a time to go back to bed, and stick to it. For example, if you decide to go to bed at 11 PM every day and wake up at 7 AM the next day, you must adhere to this principle at all costs. You should not stay in bed any longer just because you toss and turn before falling asleep and have only slept for 6 hours. Even if you are tired, you should get out of bed at 7 o’clock, which is the wake-up time.
It is also not a good idea to go to bed early just because you feel more tired. Professor Joo said, “Even if you endure a little, you can maintain regular sleep by sleeping at your usual sleeping time. Also, you should wake up on time in the morning as usual,” he added.
What should I do if I have trouble falling asleep? If you keep lying down, your brain may become more alert. At this time, you should reduce the time you go to bed. First, get out of bed and go into the living room. Rest for a while and when you feel sleepy, go back to bed. This behavior helps the brain recognize that the bed is only for sleeping. However, even in this case, the wake-up time must be the same as usual.
Professor Joo emphasized that this type of sleep training should be continued for at least a month. If you train consistently, you will start to feel sleepy when it is time to go to bed. Of course, you should set the time you stay in bed according to your biological clock. Professor Joo generally recommended setting it within 7 to 8 hours.
It’s not a bad idea for people who lack sleep during the week to sleep more on the weekend to make up for it. However, you should stick to your usual bedtime and keep the ‘median’ difference in sleep time within 2 hours. Only then can we reduce ‘social time lag’ and prevent side effects.
For example, if you are an office worker who usually sleeps from midnight to 6 a.m., the median sleep time is 3 a.m. If this office worker goes to bed at 2 a.m. on the weekend and wakes up at 10 a.m., the median sleep time is 6 a.m. The social time difference between the two sleeps is 3 hours. Even though I only slept 2 hours more than usual, there is a high chance of getting Monday sickness. On the other hand, if this office worker goes to bed at midnight and wakes up at 10 a.m. on the weekend, the median sleep time is 5 a.m. Even though I slept 4 hours more than usual, my social jet lag is reduced to 2 hours. Professor Joo said, “If we reduce the social time difference to less than two hours, we can make up for lost sleep and lower the incidence of Monday sickness, depression, heart disease, etc.”
●Light control, essential for a good night’s sleep
Controlling the intensity of light is also absolutely necessary for a good night’s sleep. Above all, when receiving light, you must receive it clearly. Especially when you wake up in the morning, you need to expose your face to light. It is best to receive sunlight for at least 30 minutes. However, if the weather is cloudy, you cannot receive strong light. At this time, we need to find a way to replace sunlight. You can get help by using light therapy devices that are easily available on the market.
Generally, during the summer, when the sun’s rays shine brightly during the day, the intensity is more than 30,000 lux. Light therapy devices have a power of about 10,000 lux, equivalent to a clear day. On a cloudy day, it is around 100 lux. The office is usually around 300 lux, and the restroom is around 50 to 80 lux.
When using this device, keep it about 30cm away from your head. You shouldn’t look at the light source, but you shouldn’t close your eyes either. This is because light indirectly affects the eyes. Get some light while reading a book or newspaper for about 30 minutes. Professor Joo recommended a device that contains blue light, which blocks sleep. Blue light is light that disturbs sleep. However, it definitely plays a role in waking you up in the morning. This helps change the sleep cycle.
Many people wear sunglasses on their way to work or while exercising in the morning to block ultraviolet rays. Professor Joo also said, “It is a bad habit that disturbs a good night’s sleep.” Professor Joo added, “Receiving a lot of light in the morning, of any kind, is helpful for a good night’s sleep.”
Conversely, light should be limited after the sun sets. Professor Joo recommended setting the living room kitchen to less than 150 lux after sunset. You should limit exposure to light 3 hours before going to bed. This is because melatonin, the sleep hormone, is secreted. Of course, blue light must also be blocked at this time. From this point on, he recommended only allowing dim lighting of 50 lux or less. Professor Joo said, “To sleep well at night, you need to limit the lighting to a level where you can’t see the writing on the paper.” Cell phones also interfere with sleep. This is because light from mobile phones is transmitted to the brain through the eyes and suppresses the production of melatonin hormone.
●Night snacks disturb your sleep at night
It is best to remove factors that interfere with a good night’s sleep. First of all, after dinner, you should not eat late-night snacks or drink water as much as possible. Professor Joo said, “If you eat late at night, even though it is time to sleep, your brain is active the same way as during the day, such as secreting digestive juices. “Because of this, I can’t get a good night’s sleep.” If this happens repeatedly, sleep time gets pushed back further and further. In that case, you may become nocturnal and not be able to sleep at night.
Some people complain that they cannot sleep unless they eat because they feel very hungry. In relation to this, Professor Joo said, “Situations where physical activity is active or a lot of energy is needed at night when one should be sleeping rarely occur. However, feeling hungry despite this is called ‘false hunger.’” As eating habits become disrupted, the brain mistakenly recognizes that one is hungry. Rather, if you eat a late-night snack at this time, it can put a strain on organs such as the heart and liver.
There are teas that are known to help you sleep. Chamomile is a representative example. However, it is best not to drink these teas 3 to 4 hours before bedtime. Professor Joo said, “Drinking tea before bed causes enuresis during sleep, which actually disturbs a good night’s sleep.” Moreover, there is little medical evidence or clinical trials showing that these teas help sleep.
There is a time when deep sleep occurs. Between 11pm and 2am. The time zone may vary depending on the type of biological clock, but most people in their 40s and older get a good night’s sleep during this time zone. If you miss this time period, you may not feel refreshed in the morning and may feel more tired.
If done well, exercise can help you sleep, but if done poorly, it can interfere with a good night’s sleep. Professor Cho said, “Exercising regularly will help you adjust your sleep cycle,” but added, “However, you should avoid it right before going to sleep.” If you exercise vigorously around this time, your sympathetic nerves will increase abnormally, making it difficult to fall asleep. Even if you sleep, it prevents you from sleeping well because it causes you to wake up frequently. Exercising in bright lighting also helps wake up your body.
There is a different best way to exercise. First, turn down the lights. Lighting similar to dim streetlights is good. Exercise intensity should range from mild to moderate. Aerobic exercise, rather than strength training, can trigger sleep.
●If your sleep pattern is disrupted, you may become seriously ill.
If you cannot sleep properly for a long time, you may suffer from chronic diseases. However, surprisingly many people do not know that the cause of the disease is a disruption in sleep patterns. This was the case for Mr. A, a 58-year-old man who recently visited Professor Joo.
Mr. A has suffered from severe snoring since he was young. However, he fell asleep very easily and rarely woke up during the night, so there was no doubt that he had a sleep disorder. Then he woke up to the feeling of his chest pounding. I couldn’t breathe well. In the middle of the night he went to the emergency room and was diagnosed with cardiac arrhythmia. Later, Mr. A was found to have coronary artery stenosis and was also diagnosed with severe sleep apnea. This is a case of severe sleep apnea worsening into heart disease. In fact, in this case, the risk of heart disease is about twice as high.
Mr. B, a 69-year-old man, came to the hospital due to forgetfulness. He never drank or smoked, but from a young age he had snoring and apnea. As a result of a test at the memory clinic, Mr. B was diagnosed with ‘mild cognitive impairment.’ Mr. B also suffered from severe sleep apnea. Because he was neglected for too long, his brain aged significantly and his brain blood vessels were also damaged, leading to cognitive impairment.
Both Mr. A and Mr. B learned this fact through polysomnography. Professor Joo said, “If you haven’t had a good night’s sleep for a long time, sleep apnea may be the cause. “If you do not know this and rely only on drugs such as sleeping pills, you can develop the disease,” he said. Professor Joo continued, “If insomnia symptoms persist, the cause must be discovered through polysomnography.”
| ＜Creating lifestyle habits for a good night’s sleep＞
Go to bed and wake up regularly. Source: Joo Eun-yeon, Professor of Neurology, Samsung Seoul Hospital |
Reporter Kim Sang-hoon corekim@donga.com
2024-04-27 00:15:36