HOW WE GOT HERE

It’s fair to say that almost everyone could use better sleep which is what motivated our team to create Sleepman – a well being partner for everyone! We have been working on bringing a good night’s sleep to the world for more than two years and now we are ready to share Sleepman with you.
We have refined and tested the most effective bio-tracking technologies and implemented them into state-of-the-art hardware and software, all in the comfortable design of Sleepman. Working prototypes of Sleepman were introduced at NBC4 News Health & Fitness Expo in May 2016.

Sleepman Science

From blueprints to the New York Fitness Expo!

Sleepman Hardware
Includes a 6 axis Accelerometer / Gyro meter and a Bluetooth module
Finally: working prototype!
Sleepman teardown

More About SleepmanTM – Problem Overview & Stats

This is an overview of a scientific background underneath Sleepman operations presented in a simple and clear way. For those who’d like to dive deeper into a science of sleep, fatigue and tracking techniques, we’ve provided an extensive list of references to specialized scientific papers, reports and other relevant publications; most of them can be accessed online through the provided links. This overview of scientific findings is for information only but neither for commercial nor advertisement purposes.

WHY DO YOU NEED SLEEPMAN?

GOOD SLEEP… It is vital for our very existence. Nothing impacts us as badly as a sleep deficit. Daytime drowsiness ruins our health, worsens work performance, makes us irritated, unhappy and harms our social life.
Insufficient night sleep impacts our mood, productivity and creativity, reduces ability to think and learn and impairs attention, alertness, concentration, reasoning and problem solving. Sleep disorders and chronic sleep loss can put us at a higher risk for cardiovascular deceases, strokes and other health problems; e.g., [1].
Researchers have found that reducing nighttime sleep by as little as one and a half hours for just one night could reduce daytime alertness and performance by as much as 32% [2]. Lack of sleep increases the risk of occupational injury by 61% [3], doubles the risk of heart decease, diabetes and stroke [4] and increases the risk of depression by 10 times [5]. According to a 2004 study [1], people who sleep less than six hours a day were almost 30 percent more likely to become overweight than those who slept seven to nine hours.
Daytime drowsiness is also a big public safety hazard every day on the road. Drowsiness can slow reaction time as much as driving drunk. The National Highway Traffic Safety Administration conservatively estimates that 100,000 police-reported crashes are the direct result of driver fatigue each year which results in an estimated 1,550 deaths, 71,000 injuries, and $12.5 billion in monetary losses. These figures may be the tip of the iceberg, since currently it is difficult to attribute crashes to sleepiness. The 2009 Massachusetts Special Commission on Drowsy Driving, based on a different research methodology, estimated that there could be as many as 1.2 million crashes, 8,000 lives lost, and 500,000 injuries due to drowsy driving each year; [6], [7].
Lack of sleep-induced cardiovascular diseases includes heart arrhythmias. It was found that about 14 million people in the USA, or about 5% of the population, have arrhythmias [8], and about 80% of sudden cardiac death result from ventricular arrhythmias [9]. Arrhythmias may occur at any age but are more common among older people.
Do we always get enough sleep? Unfortunately most of us never sleep long enough: we may be too busy, work odd hours, care for babies or have sleep problems and so feel drowsy and tired quite often.
According to the National Sleep Foundation (NSF), “As a nation, the United States appears to be becoming more and more sleep deprived” [10]. The US Centers for Decease Control and Prevention (CDC) identified insufficient sleep as a public health problem and reported that an estimated 50-70 million US adults have sleep or wakefulness disorder and 37.9% reported unintentionally falling asleep during the day at least once in the preceding month [11]. The results of comprehensive studies of the lack of sleep-related problems and detailed statistics were summarized by the NSF in [12], and it was reported that around 87% of people are suffering from sleeping problems throughout their lives. According to Forbes, at least 40 million Americans experience chronic sleep disorders and report that poor sleep regularly affects their lives [13].
If you don’t get enough sleep, suffer from insomnia or experience daytime drowsiness, Sleepman can help you to fully eliminate or at least significantly mitigate your problems.

SCIENTIFIC BACKGROUND FOR SLEEPMAN OPERATIONS

Sleepman operations are based on accumulated scientific knowledge about sleep, alertness level and drowsiness. Sleep has been studied for decades around the world and literally thousands of scientific papers and reports summarize a vast knowledge accumulated in this field. We don’t intend to review the diverse research: only findings relevant to Sleepman operations and a few basic references are given below.
Scientists found that during a sleep one goes through a sequence of approximately 90-min-long cycles and each cycle may include up to four distinctive sleep stages; [14] – [17]. A typical sleep pattern is illustrated in Figure 1 as a commonly used diagram, also called a hypnogram. Sleep stages are divided into Rapid Eye Movement (REM) stage and 3 non-REM (NREM) stages. For decades scientists have used four NREM stages but not far ago the American Academy of Sleep Medicine combined stages 3 and 4 into one stage 3; [15]. However, 4 NREM stages are still shown in most hypnogram like that in Figure 1a.

Sleepman graphs1

Figure 1: Typical hypnogram of sleep stages (a); and typical electroencephalograms (EEG) for each stage (b). The plots are reproduced from [14].
NREM stage 1 is usually referred to as a light sleep or a drowsy sleep and for adults it occupies around 5% – 10% of a total time of sleep. This stage is the lightest sleep between deeper sleep and wakefulness when muscles are still active and eyes may open and close moderately; [16], [17]. All scientists agree that this is the best and the only sleep stage when a person awakes well rested, fully refreshed and energized while one feels half-asleep and groggy when awaken in any other sleep stage, even after a long sleep; [17], [18].
NREM stage 2 is usually referred to as a moderate or shallow sleep and for adults it occupies around 45% – 55% of total sleep time; [19]. In this stage muscular activity decreases, conscious awareness of the surroundings disappears and it is harder to awake a sleeper in this stage; [20].
NREM stage 3 is usually referred to as a deep sleep and for adults it occupies around 10% – 25% of a total time of sleep. Formerly divided into stages 3 and 4, this stage is called a slow-wave sleep (SWS) or deep sleep when a person does not react to surroundings. SWS stage is the most restful form of sleep, the stage which most relieves subjective feelings of sleepiness and the most effectively restores the brain and body; [21]. However, the fraction of the deep sleep gradually reduces with age from about 20% for 20 to 25 year olds to about 10% for 40 to 50 years old healthy people; [16], [22].
REM stage is often referred to as a dreaming sleep and for adults it occupies around 20% – 25% of a total sleep time; [23]. In this stage a sleeper usually experience vivid dreams and it is harder to arouse during the REM than at any other sleep stage; [20].
As illustrated in Figure 1a, sleep stages alternate continually during the night and their durations vary rather irregularly. At the same time, the only “right stage” for awaking a sleeping person well rested and full of energy is the NREM stage 1 – the light sleep. To catch the “right time”, a “smart” alarming device must track the stages during a sleep.
The tracking may be executed by monitoring person’s movements or/ and physiological parameters such as pulse rate, body temperature or the most informative one – a brain activity. Monitoring movements of hands, eyes or body may be performed by accelerometers, video cameras and alike. However, the movements during a sleep are highly individualized: some people may sleep “like logs”, others move quite often. Moreover, the person movements may change from night to night and during the night depending on how stressful was a day, what and how much food and drinks one had at a dinner and many other factors. Therefore tracking sleep stages through movements may be ambiguous and inaccurate.
On the contrary, the brain activity is directly connected to all physiological processes in our bodies and our mental state. Our brain works as an electro-chemical “reactor”. Neurons in the brain generate electromagnetic signals which go along nerve fibers to all muscles in our body. These electromagnetic bio-signals are related directly to our sleep stages and level of alertness and they change radically when our sleep stages change or we go from the full alert state to relaxation, tiredness and to drowsiness. Typical electroencephalograms (EEG) for different sleep stages and level of alertness are illustrated in Figures 1b and 2a.

Figure 2: Typical brain waves, corresponding to different level of alertness (a); and percentage of fatigue-induced crashes versus time of driving (b). The plots are reproduced from [24] and [25], respectively.
Measuring EEG is neither preferred nor necessary technology for monitoring brain signals. Standard EEG applications require from 10 to 20 electrodes placed on the scalp with a conductive gel or paste in the specified locations [26]. Wearing multiple electrodes is inconvenient at night and practically unacceptable at a daytime.
The bio-signals propagate through nerve fibers to control all muscles in our body and can therefore be monitored almost anywhere. After extensive search over tested technologies for sensing bio-signals, we’ve chosen the Electro Dermal Activity (EDA) approach utilizing variations in the electrical characteristics of a skin; [27] – [29]. We’ve selected this approach because it has been used successfully for more than two decades and EDA-sensing techniques and tracking algorithms are the most developed, well-tested, reliable and nonintrusive; [30] – [33]. EDA-based technologies ensure reliable tracking of both sleep stages and daytime level of alertness. As illustrated in Figure 2a, the levels are also well-detectable with bio-signals.
Drowsiness is a hidden enemy which occurs and acts way before one actually feels it. It was found that an average healthy person becomes tired and drowsy after 3 – 4 working hours. In particular, significant increases in driver errors and significant decreases in driver level of alertness began to show as early as the 4th hour of driving time as illustrated in Figure 2b; [34], [25].
Monitoring eye or head movements does not guarantee timely detection of fatigue or drowsiness: when a head nods or eyes are closed for a few seconds, it may be too late, e.g., when you drive at 65 mph or operate heavy machinery. Tracking bio-signals ensures detecting the earliest signs of loss of concentration before a person feels it and alerting the person in advance that it may be unsafe to continue working without a break.
However, just warning a person about fatigue or drowsiness is often not enough. When a driver must continue his trip or an office worker must meet a deadline for the urgent project, he or she cannot just go home and get a good sleep. Fortunately scientists have found a powerful tool to fully recharge a person for several hours of intensive work – the Power Nap.
“Ever since sleep scientist David Dinges helped found the modern science of napping in the early ’80s at the University of Pennsylvania School of Medicine, short periods of sleep have been shown to improve alertness, memory, motor skills, decision-making, and mood”; [35]. Dr. Sara Mednick, a scientist at the Salk Institute for Biological Studies and Assistant Professor of Department of Psychology at the University of California, Riverside, who is at the forefront of napping research, gave simple and clear explanation for a power nap. “So what makes a power nap effective? Think of it as an investment with the greatest return in the least amount of time, a kind of super-efficient sleep that fits nicely in a high-pressure schedule: say, between business meetings or in the minutes before a game. Napping in general benefits heart functioning, hormonal maintenance, and cell repair… A power nap simply maximizes these benefits by getting the sleeper into and out of rejuvenative sleep as fast as possible. Here’s how the power nap works: Sleep comes in five stages that recur cyclically throughout a typical night, and a power nap seeks to include just the first two of them. The initial stage features the sinking into sleep…The second is a light but restful sleep in which the body gets ready for the entry into the deep and dreamless “slow-wave sleep,” that occurs in stages three and four. Stage five, of course, is REM, when the eyes twitch and dreaming becomes intense… Experts believe that the optimal power nap should roughly coincide with the first 20 minutes in order to give you full access to stage two’s restorative benefits… When you wake up, your neurons perform the same function as before, but now faster and with more accuracy”; [36], [17].
The National Sleep Foundation recommends using power nap as the restoration tool. “A short nap of 20-30 minutes can help to improve mood, alertness and performance… without leaving you feeling groggy or interfering with nighttime sleep. Naps can increase alertness in the period directly following the nap and may extend alertness a few hours later in the day. …Taking a short nap before driving can reduce a person’s risk of having a drowsy driving crash”; [10].
It’s not surprising that employers have been more and more recognizing and even encouraging short power naps. As reported in [35], “With Americans averaging fewer than seven hours of sleep per night — and around 20 percent suffering from sleepiness during the day, according to a recent Stanford University study — many companies have turned to the humble nap in an attempt to stave off billions in lost productivity each year. “Tiny naps are much more refreshing than people tend to realize,” said Jim Horne, director of the Sleep Research Centre at Loughborough University in England. “A short nap in the afternoon will get rid of sleepiness without interfering with nighttime sleep.” The “Fortune” wrote: “Americans are logging longer hours at work than ever before, and there’s some evidence that companies are becoming more lenient — even encouraging — toward at-work napping. According to an employee benefits survey of 600 American companies conducted by the Society for Human Resource Management, 6% of workplaces had nap rooms in 2011, a slight increase from 5% the previous year. Even more suggestive, a 2011 poll of 1,508 adults by the National Sleep Foundation found that 34% of respondents say their employers allow them to nap at work, and 16% said their employers also have designated napping areas”; [37].

More questions?

Please let us know if you have questions about scientific background for Sleepman operations that are not answered on our website. We’ll be glad to address them and include the answers in this document.
THANK YOU VERY MUCH FOR YOUR INTEREST IN SLEEPMAN!

References

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