Sleep Monitor: Detects sleep and helps you sleep soundly

Sleep is the longest part of a person's life, accounting for about one-third of his life. A good night's sleep every day is essential for improving the quality of life and work and maintaining health. Therefore, the number of applications of technology that measures and digitizes sleep status has begun to increase.

Daily sleep is essential to relieve physical and mental fatigue and restore energy. The most suitable sleep time varies from person to person, generally between 6 and 8 hours.

然而，大家都有过明明晚上睡得很好但白天还要犯睏的经历吧。也有即使保证了睡眠时间，但一直处于浅睡状态而消除不了疲劳的情况。因此，睡眠的“质”比“量”更为重要。

If daily sleep conditions can be detected and digitized like a scale or thermometer, it will help improve sleep quality. In this regard, a technology called "sleep monitor" has attracted attention. This technology can grasp the depth and state of sleep based on biological sign data measured during sleep.

TANITA of Japan has launched a mat-shaped sleep monitor called "Sleep Scan" that is placed under a mattress or quilt. The biological data measured are breathing, pulse, and body movements during sleep. The mat is constructed with multiple tubes tightly attached, and the tubes are filled with water. The working principle is that the water in the tubes captures the weak vibrations caused by breathing and pulse during sleep, as well as body movements, and transmits them to the pressure sensor.

The mixed information of breathing, pulse and body movement transmitted by the sensor is decomposed by the signal processing circuit and the information is divided into three data outputs: breathing, pulse and body movement. The output data is saved in the SD card and analyzed using computer-specific software.

Sleep states are generally divided into rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. REM sleep refers to a state in which the body is resting but the brain is active. Non-rapid eye movement (NREM) sleep is a state in which the brain is also resting. NREM sleep can be further divided into multiple stages according to the depth of sleep.

After falling asleep, non-rapid eye movement sleep appears first, and then transitions to rapid eye movement sleep within 1 to 2 hours. After that, non-rapid eye movement sleep and rapid eye movement sleep alternate, and rapid eye movement sleep lasts for 10 to 20 minutes every 90 minutes. In a night's sleep, this cycle usually repeats 4 to 5 times. Dreaming mostly occurs during the rapid eye movement sleep when the brain is active.

The Sleep Scan software analyzes the sleep state you experience during sleep based on the measured breathing, pulse and body movement data. For example, if your body movement is low and your breathing and pulse are stable, you can be judged to be in deep sleep.

The sleep state is plotted in chronological order as a curve graph, showing the length and depth of non-rapid eye movement sleep, the number of awakenings, etc. at a glance. In addition, the "sleep score" as a measure of sleep quality can be calculated. That is, the score is calculated by comprehensively judging the time to fall asleep, the length of deep sleep, the number of awakenings and body movements, and the proportion of actual sleep in the time lying in bed (sleep efficiency).

The higher the sleep score, the faster you fall asleep. However, just as normal body temperature varies from person to person, there are also individual differences in sleep scores. Toshiaki Sasaki of the Bailida Development Department said, "It is best to observe the changes in the score every day and use it as a standard to determine whether you sleep better than usual."

For example, if your score is usually around 70, but this time it is 30, then there must be something that caused the score to drop. At this time, you can check the curve graph, and if you find that you wake up many times at night, you can take measures such as paying attention to the room temperature or reducing drinking before going to bed. In this way, you can easily grasp the quality of sleep, just like a "sleep meter".

Adjust the room temperature to a level that is easy to fall asleep at

Daikin Industries has used sleep monitoring technology to develop a solution that can automatically adjust the air-conditioning temperature to the optimal state according to sleep rhythm.

Last year, Daikin Industries launched a remote control called "soine" that can be used to control its air conditioners. The hollow tube attached to the remote control is placed under the mattress and quilt, and the breathing, heart rate (pulse) and body movement during sleep can be measured based on the changes in air pressure in the tube.

As we all know, after falling asleep, the body temperature usually drops slowly (up to 2 degrees), and rises before waking up. Therefore, while detecting the sleeping state, soine will instruct the air conditioner to appropriately lower the room temperature after falling asleep. And it will start to raise the room temperature about 1 hour before the pre-set wake-up time. In other words, it helps adjust the room temperature under the natural changes in body temperature to improve comfort.

In addition, based on this temperature regulation, soine will also carefully adjust the room temperature during sleep.

It is known that the thermoregulatory function works differently during REM sleep and non-REM sleep. The thermoregulatory function works during non-REM sleep, but it is difficult to work during REM sleep. Night sweats often occur during non-REM sleep.

During sleep, when you switch from NREM to REM sleep, Soine will instruct the air conditioner to temporarily raise the room temperature. This is because it is necessary to prevent the body temperature from dropping too much when the body temperature regulation function is difficult to function. After 10 to 20 minutes, REM sleep ends and you switch to NREM sleep, at which time Soine will appropriately lower the set temperature.

Takehiko Ei of Daikin Industries, which participated in the development of Soine, explained, "The results of the study showed that if the room temperature is adjusted according to the sleep rhythm, the deep sleep of non-rapid eye movement sleep and rapid eye movement sleep will increase by 20% compared to when the temperature is fixed, and the number of awakenings in the middle of the night will decrease." In recent years, due to the increase in hot nights in summer, the number of people sleeping with air conditioning on has increased. Sleep monitoring technology is also an effective means to create a comfortable sleeping environment.

It can also be used for "care" of the elderly

There is also a move to develop products for use in the nursing field, using monitoring technology to monitor the sleep status of elderly people who need care, in order to reduce the burden on caregivers.

Bam Labs (California), an American venture company, has developed a sleep monitor that uses a single-size sensor mat placed under the mattress and futon. The sensor collects information about breathing, pulse, body movement, and getting in and out of bed based on changes in air pressure inside the mat.

The data is sent to a dedicated server via the Internet. Caregivers can access the server through a computer or mobile terminal to confirm the sleep status of the person being cared for at any time.

Currently, Bam Labs' general agent Healthcare-Tech (Fuchu City, Tokyo) is conducting a demonstration experiment at its group nursing facilities.

For example, if a person's pulse rate drops from 60 beats per minute to 40 beats per minute during sleep, it can be determined that something is wrong with the body, and the caregiver will rush to check. It can also confirm whether an elderly person with dementia gets out of bed at night, and if he or she does not return for a long time, it is necessary to pay attention to his or her wandering behavior and take countermeasures. There is also a function that notifies the caregiver through an alarm when the elderly person is about to get in or out of bed.

In care facilities where multiple elderly people need to be cared for at the same time, the monitor can reduce the burden on caregivers to conduct regular inspections and check biological data. In addition, if someone does not sleep well at night, measures can be taken during the next day's care, which will help improve care services.

Healthcare-Tech President Kenichi Watanabe said: "The biggest advantage of this monitor is that it can monitor sleep status in real time. In the future, we will find effective on-site usage and marketability through empirical experiments and start business operations."

One third of our life is spent on sleep. There is still a lot of room for the application of this monitoring technology to be expanded. In the future, it is expected to be applied to improving the living environment, medical treatment and work efficiency, etc.