Capturing Awakenings for Better Sleep – Medical Frontiers
[Music] [Music] Do you struggle to fall asleep or wake up repeatedly during the night or feel exhausted even after a full night’s rest? You’re certainly not alone. And in Japan, researchers are taking a fresh approach, shifting their focus to the moments of wakefulness that occur during sleep. These awakenings could be a key to understanding and also treating insomnia. On the program today, we’ll explore the groundbreaking work of Japanese scientists uncovering the hidden role of nighttime awakenings. Why people sleep and wake remains one of the greatest black boxes of modern science. Researchers around the world are working to unravel its mysteries. Analyses of brain waves show that sleep is largely divided into four stages. [Music] After falling asleep, we enter deep sleep known as nonREM sleep. NonREM sleep has three stages. Stage one, stage two and stage three. Each stage brings us into a deeper level of sleep. It is believed that both the brain and the body rest during nonREM sleep. We eventually shift to REM sleep. During REM sleep, the body rests, but the brain is active, carrying out tasks such as processing memories. It’s also the stage when dreams are said to occur. While cycling through REM and nonREM sleep, the brain sometimes transitions into another stage. It’s called wakefulness. [Music] Even healthy people experience brief awakenings dozens of times during sleep. However, because these awakenings are so short, people typically don’t remember them. When periods of wakefulness during sleep become more frequent, people begin to feel they are suffering from insomnia. [Music] One example is midsleep awakenings. Stress, nightmares, or disruptions to the body’s internal clock make it difficult to fall asleep after these awakenings. [Music] Early morning awakenings, when a person wakes up earlier than intended, can also cause a feeling of sleep deprivation. This often occurs in people with depression as stress and other factors can reduce the secretion of hormones that promote sleepiness. A study in the United States found that older women who spent more time awake in bed had a 1.57 times higher risk of developing dementia or mild cognitive impairment within 5 years compared with those who got enough sleep. [Music] [Music] A research team at the University of Tokyo developed an algorithm that helped create a device to prevent insomnia. The leader of the research team, UA Hiroki, has published a series of sleepreated studies in international scientific journals such as Nature. Leda is currently also based at the University of Oxford in the UK where he is conducting sleep research with European researchers. So, Professor Wed, thank you so much for your precious time today. Now, you and your team developed this really interesting device which measures wakefulness during sleep. Yeah. So uh so there are many disease like a depressions or uh or dementia or u schizophrenia or many uh brain related diseases and then individual uh brain related diseases have its own unique u sleep patterns. So therefore we like to identify u such kind of a unique uh sleep patterns for the prevention of these diseases. So that is why we focusing on the uh sleep quality. UA and his team focused on a specific movement that people often make when they have a nighttime awakening. With the cooperation of UEA’s research team, we monitored the sleep of one of our crew members. 1 hour after the experiment began, he entered nonREM sleep, which indicates deep sleep. 3 minutes later, his brain waves showed signs of wakefulness. When his brain waves indicated awakening, his arm moved noticeably. Shortly afterward, his brain waves again showed signs of wakefulness. He moved his arm again, scratching his neck. His arm moved nearly every time. His brain waves indicated wakefulness. Again he moved his arms touching his stomach and face. [Music] [Music] [Music] That night, the brain waves indicated 10 short awakenings with arm movement in nine out of 10. [Music] A wristworn device was developed to capture such movements based on ongoing research by UEA and his team. [Music] Many devices have been developed in the past to monitor arm movement during sleep, but accurately detecting awakenings has remained a challenge. [Music] The research team focused on a key point. When the arm moves during sleep, it does not move at a constant acceleration. Instead, the acceleration varies. [Music] The team aimed to capture these fluctuations. They focused on an indicator known as jerk, the rate of change in acceleration. By calculating jerk, feeding the data into a computer and comparing it with brainwave data, they developed a unique algorithm that distinguishes between sleep and wakefulness. The upper graph shows brain waves during sleep and the bottom graph shows jerk. When the brain waves indicated wakefulness, the arm’s jerk value rose significantly. The timing of the brain wave activity and jerk were almost the same. [Music] The device matched arm jerk with brainwave detected awakenings with at least 80% accuracy. [Music] The results were published in an international scientific journal. The device is now beginning to be used in clinical settings. This clinic introduced the device to assess sleep quality as part of its standard health checkups. This man in his 20s had been complaining of insomnia for about two years. He was under stress from working long hours of overtime. He measured his sleep data for a week using the wristworn device. [Music] This is the data from that period. The vertical axis shows the time. The public health nurse providing sleep guidance pointed out that Saturday’s sleep was especially problematic. The blue areas in the graph represent sleep. The red areas indicate wakefulness. It’s clear there were multiple awakenings during the night. What’s more, it took him over 2 hours to fall asleep after going to bed. Lying awake and feeling unsettled is a type of insomnia known as sleep initiation disorder. His bedtime and wake up time were also much later than on other days. Looking more closely at his results, his total sleep time was 5 hours and 26 minutes with 46 minutes spent awake. His sleep efficiency or percentage of time asleep while in bed was 62%. This is very low compared with the healthy benchmark of 85% or higher. The nurse also pointed out his dinner habits. The man stopped eating late at night and began exercising to help himself fall asleep. He also tried to get up at the same time every day. Here is his sleep data from 5 months later. He fell asleep more quickly after going to bed, showing improvement in his sleep initiation disorder. The difference in his wake up times between weekdays and weekends was 2 hours or less. Looking at the numbers, the amount of time he was awake during the night hadn’t changed, but because he was falling asleep more easily, he was able to get more sleep overall. As a result, his sleep efficiency reached the ideal level of 85% or higher on most days. [Music] [Music] [Music] many. Many researchers have searched for a substance that acts as a switch for sleep. In 2016, UEA published a study in an international scientific journal showing that a substance once thought to keep us awake actually triggers sleep. The discovery attracted the attention of scientists around the world. [Music] UIDA did computer simulations to explore how brain neurons behave in mice during wakefulness and deep sleep. [Music] These graphs show the activity of the neurons during the two states. [Music] During wakefulness, the brain neurons remained active and the brain waves fluctuated continuously. But during deep sleep, the neurons followed a regular cycle of activity and rest. [Music] The research team thought that the mechanism controlling sleep might lie within the brain’s neurons during sleep. They closely examined the mice’s sleep and discovered a substance that plays a key role in regulating sleep and wakefulness. [Music] That substance is calcium. [Music] UA’s team conducted experiments using mice in which calcium was blocked from entering the neurons. These images show the mice’s brain neurons. The left side shows a normal mouse brain. The right side shows a mouse brain in which calcium was blocked. Its neurons glow bright green, indicating high activity. This suggests that the mouse’s sleep is significantly suppressed. [Music] So do you think the discovery of of calcium being this major switch was a key discovery? When I started the sleep research uh you know or we tend to focus on the sleep substances. So but but uh when we come up with the completely opposite idea that was a kind of a moment uh for us we start to say discovering the new mechanism how can we treat uh schizophrenia or depressions. So therefore if you understand uh uh like what how our brain activity are moderated or formed we start um kind of a understanding how can we treat uh such a extreme um condition like uh diseases. Okay great. Do you think that this key discovery can lead to the development of you know future sleep medications? Yeah I guess so. Oh, I believe so. Of course, you know, not a single research cannot be to go such kind of a new treatment. Uh so, so therefore we need to have follow-up study to identify the the kind of a good entry point to regulate sleep especially sleep quality. Hopefully near future we’d like to develop the how we can kind of deepen um uh the our sleep. Professor I mean it said that for example traditionally that we were you know encouraged to drink a cup of hot milk before bed. Is it true that then consuming calcium can lead to deeper sleep? I would like to say yes but we still don’t know yet. One drink of uh hot milk might not be enough might not be enough or might not be contributing to your brain calcium uh because calcium concentration is usually tightly uh how to say uh regulated and professor Wo and finally are you getting enough sleep these days? Yes. Uh so usually uh I have a sufficient amount of sleep and more than seven hours and sometimes eight hours. Uh so that’s good but sometimes you know uh excitement is coming from the sleep research which make us make me how to say uh wake. So sometimes I have a insomnia. Yeah. And thank you so much. Thank you for having me. Uh, [Music] many people with insomnia take sleeping pills. The Japanese Society of Sleep Research says that one in every 20 Japanese adults uses sleep medication. Of those, 80% are prescribed sleeping pills that are strong and fast acting. [Music] We spoke with Uchimura Naisa, president of the Japanese Society of Sleep Research about the proper use of sleeping pills and how to deal with insomnia without relying on medication. The health world at the moment. So I think many people professor who are struggling with insomnia are a little bit hesitant or reluctant to take sleep medication. Should they still consider it as an option to get some sleep? Foreign speech. Foreign speech. Foreign speech. Drugs called Orexen receptor antagonists are currently attracting attention. They were developed through a different approach from conventional sleeping pills. Orexen, the substance that forms the basis of the drugs, was discovered in 1998 by a team led by University of Scuba Professor Yanagi Sawa Masashi. Orexin is a chemical secreted from a part of the brain called the hypothalamus. [Music] It’s involved in exciting or suppressing nerve activity and is continuously released while we are awake. When erection is released and binds to neurons, the brain wakes up. But ifin is not secreted and does not bind to neurons, the brain enters a sleep state. Anxiety and stress can activate causing wakefulness to continue even after bedtime. Rexin receptor antagonists work by blocking erection, preventing it from stimulating neurons and thereby inducing sleep. [Music] Because these drugs support the body’s natural sleepwake mechanism, they are considered to promote more natural sleep. [Music] Do they have any side effects at all? Oh, Ichimura places importance on cognitive behavioral therapy or CBT as a method for treating insomnia. [Music] In CBT, patients work with a specialist to reassess their daily habits and identify the severity and causes of their sleep problems. Its goal is to ease anxiety and restore healthy sleep. A research team that included the University of Tokyo analyzed various data to learn about the effects of CBT and published their findings in 2024. The study found that 28% of people who only took medication, including sleeping pills, experienced long-term improvement. The figure was 40% for those who used both medication and CBT and 41% for those who only had CBT. Uchimura recommends keeping a sleep diary as a simple way to practice CBT. He suggests the following steps. Step one, let go of your stress. Before bedtime, write down anything that caused stress or discomfort that day. Don’t spend too long on this as dwelling on it might bring the stress back. Around 15 minutes is enough. [Music] Step two, forget what upset you. If you still feel unsettled after writing, you can black out what you’ve written or tear out the page and throw it away. [Music] Step three, leave the day behind. Once you’re done, close the diary and tell yourself the day is over. Let go of your worries and go to sleep. In the morning, write down how many hours you slept. Try to track every day if possible. How long should they keep a sleep diary to see the results? [Music] Thank you so much, Professor. As we’ve learned, sleep is far more than just a nightly routine. It’s a cornerstone of our health and well-being. So, the message is clear. Prioritizing sleep is essential and I encourage you to take a moment to reflect on how you can optimize and improve your sleep. [Music] Oh, [Music]
[Skip Intro] 00:07
Watch full episodes of Medical Frontiers on NHK WORLD-JAPAN!
https://www3.nhk.or.jp/nhkworld/en/ondemand/program/video/medicalfrontiers/?cid=wohk-yt-2508-mf173-hp
Watch more quality programs on NHK WORLD-JAPAN!
https://www3.nhk.or.jp/nhkworld/en/ondemand/video/?cid=wohk-yt-2508-mf173-hp
Japanese researchers investigate treatments for reducing stress and improving sleep quality in patients suffering from insomnia.