Have you ever awakened after a seemingly good night’s sleep yet not felt refreshed? Feeling groggy in the morning might have something to do with the quality of your sleep.
Dr. Jason Lin, director of the Department of Neurology and Stroke Center of Taiwan’s Lin Shin Hospital and attending physician of the Department of Neurology, introduced seven methods to improve sleep quality in a “Health 1+1” program to help you get a full night’s sleep.
Dr. Lin pointed out that poor sleep quality may be due to several factors. One is that the sleep time is too brief, and another is that although sleep might appear long, you may not be getting to the “deep sleep” state. In other words, you’re not attaining a “complete sleep structure.”
What Is a Complete Sleep Structure?
Dr. Lin explained that sleep is divided into two major stages, the non-rapid eye movement (NREM) stage, and the rapid eye movement (REM) stage.Stage 1: NREM
NREM can be sub-divided into three stages:1. Very light sleep. During this period, brain waves gradually slow down, and you will feel that you have entered a different world as if you are waking up and falling asleep alternatively. This stage accounts for about 5 to 10 percent of total sleep time.
2. Light sleep. This period accounts for most of sleep time, in which breathing, and heartbeat continue to slow down, and muscles continue to relax, all in preparation to enter a deep sleep state.
3. Deep sleep. This is a period when the brain waves are extremely slow and the whole body is completely relaxed. After entering this stage, it is difficult to be woken up, and even after being woken up, response is still slow.
Usually, if a person feels that they have not slept enough, it indicates their state of sleep continues to be in the first and second parts and has not reached deep sleep.
Stage 2: REM
The REM sleep stage is the most common period of dreaming. Within this stage, the sleeper’s eyes are in rapid movement and the muscles of the whole body are in a relaxed state.In general, the transition from NREM to REM as one cycle takes about 90–120 minutes. That means if you sleep for seven to eight hours, you will go through four to five such cycles.
An electroencephalogram (EEG) can be used to monitor eye movements, muscle activities, and brain wave frequencies during sleep—this is one way to determine having moved into the deep sleep state. To do the same without resorting to instruments, we can simply judge our quality of sleep based on how energized we feel after waking up, whether we feel the need to sleep in the afternoon, the status of memory and concentration, etc.
The Epworth Sleepiness Scale is often used to evaluate sleepiness. If the score exceeds 11, it means that you are prone to dozing off during the day, and it also indicates that you do not sleep well at night.
4 Main Functions of Sleep
Sleep is important because it has the following four functions:1. Secretion of growth hormone
11 p.m. to 3 a.m. is the most important period for the human body to secrete growth hormone. It can help children grow, adults repair their muscles, bones, and other tissues for growth, as well as improve immune function.2. Remove toxins from the brain
The brain has a lymphatic system like a sewer network, which opens during one’s rest at night to discharge toxins and waste from the brain. Light sleep will affect the opening of the lymphatic system, which is detrimental to the excretion of metabolites or toxins from the body. Over time, it will have an impact on brain nerves, cognitive functions, and the autonomic nervous system.3. Consolidate memory
A healthy brain will experience dreaming during sleep. Dreaming helps the brain to be selective in completing tasks such as reorganizing the memory—sorting the important from the unimportant—and safely reprocessing upsetting memories. Therefore, if you sleep well, your memory will be sharper the next day, your ability to concentrate enhanced, and upsetting memories will be lighter and easier to deal with.4. Regulate body temperature and blood pressure
The relaxation of the body that occurs during sleep can help lower blood pressure, and regulate body temperature.Poor sleep quality can lead to a number of chronic diseases, such as high blood pressure, myocardial infarction, arteriosclerosis, stroke, and increased risk of metabolic diseases such as diabetes and higher cholesterol count.
A study published in Scientific Reports” in September found that a reduction of 1.5 hours a day in sleep time can cause cardiovascular damage. For the 35 healthy women who participated in the experiment, going to bed 1.5 hours later than usual for 6 weeks, resulted in more damaging oxidants found in the endothelium of their blood vessels. In the absence of adequate sleep, the body loses part of its antioxidant resistance and fails to remove these damaging molecules.
In addition to sleep duration, sleep efficiency is also related to potential diseases. A study published in Neurology in 2020 found that when migraine patients woke up more frequently after falling asleep and with their sleep becoming more fragmented, the chance of experiencing migraine the next day was significantly increased.
Reasons for Poor Sleep
According to Dr. Lin’s clinical experience, three common causes of poor sleep are:1. Emotional stress
Our modern-day intensive, high-pressure work environments can result in symptoms of depression and anxiety as well as pave the path for poor-quality, or lack of sleep. Thoughts can be difficult to turn off causing wakefulness or light sleep—a condition of clinical insomnia.2. Feeling unwell
Physical discomforts, ranging from the troublesome reflux of gastroesophageal acid to restless legs syndrome, or even challenges like heart palpitations, asthma, and chronic pulmonary obstruction, can significantly impact the tranquility of your sleep.3. Disrupted circadian rhythm
Dozing off or sleeping during the day, as the elderly are sometimes prone to, can make it difficult to sleep at night. On the flip side, burning the midnight oil or beyond, as do many youth, can also disrupt the sleep cycle.Acute insomnia will upset circadian rhythms. If you suffer from poor-quality sleep for more than three days within a week and the condition lasts for more than a month, it is called acute insomnia. Usually, as long as you can identify the factors causing it, such as gastroesophageal reflux, or being upset, normal sleep can be restored after the physical condition or mood is relieved.
Insomnia lasting for more than three months is considered chronic insomnia. Many cases of chronic insomnia are caused by not promptly solving acute insomnia and then it becomes habitual. Even if the stress that caused acute insomnia is later resolved, insomnia will persist. Dr. Lin suggests that when insomnia starts, it must be dealt with as soon as possible, otherwise once it turns chronic, it will require more effort in its treatment.
7 Tips to Achieve Deep and Restorative Sleep
How can we achieve good quality sleep? Dr. Lin put forward seven suggestions:1. Proper adjustment of circadian rhythm
- Spend more time outdoors in the sunlight as it can help regulate melatonin secreted by the pineal gland.
- Avoid sleeping in and if you take daytime naps—keep them brief—no longer than 20 minutes.
- Hit the hay between 10 p.m. and 11 p.m. Staying up too late will affect quality of sleep.
- Keep a sleep diary. Record the time you go to bed, estimate the time you actually fall asleep, and note any time you wake up for any reason during the night. Through a sleep diary, a doctor can provide better advice to help you sleep.
3. Create a high-quality environment for sleeping
- A quiet, dark, and cool environment can help you sleep. Noise and bright light will affect sleep quality.
- People with tinnitus can find help by listening to white noise such as wind, rain, or ocean waves.
- Room temperature for optimum sleep is between 60–68 F.
4. Avoid using electronic devices before going to bed
Blue light will disrupt one’s circadian rhythm, so it is advised not to use mobile phones and other electronic devices at least one hour before going to bed.Studies have found that compared to reading printed books, reading e-books before going to bed can suppress melatonin secretion, delay your circadian rhythm, and leave you feeling less than freshly energized in the morning.
