It is known that human sleep consists of repetitive cycles of REM and NREM sleep. The average duration of each cycle is approximately one and a half hours. A good rest is sleep, which includes 5 full cycles. Thus, for maximum efficiency people should sleep at least 8 hours a day. The total duration of sleep about 80% of the slow-wave sleep. REM sleep has a shorter duration, but by the time you Wake-up its share gradually increases. Sleep cycles differ from each other not only in duration but also their functions. The slow-wave sleep helps a person to recover, the brain is in a state of rest. REM sleep, by contrast, activates the brain processes and helps to organize and remember all the important information obtained by a person in the past day. How does the device tracker that analyzes your sleep — this was in today's issue!
The Most common consumer device for determining the phases of sleep is a fitness bracelet. With the help of programmed algorithms and sensors, it determines the phases of slow and fast sleep. Among the used sensors are of particular importance sensitive recording sensor, heart rate monitor and accelerometer. The first of these records and analyzes all the sounds that a person makes during sleep. According to the observations of scientists, the REM sleep more, so if the sensor sees more certain sound than usual, this may indicate the transition to REM sleep.
But for accurate analysis of only one additional noise is not enough. In addition to identifying sounds, sleep trackers also analyze the pulse and the movement of the person. Heart rate monitor analyzes the functioning of the heart by optical plethysmography, which we have already said in one of the previous releases. An optical sensor on the back side of the bracelet radiates light on the skin and analyzes the level of its absorption, thereby determining the heart rate. With its increase, the tracker concludes that the transition from the slow phase in REM sleep. The accelerometer, in turn, keeps track of everything, even the slightest movement of the sleeping person.
Accelerometer and heart rate monitor allow you to calculate the optimal time of awakening that must occur in REM sleep. In this case, the person wakes up rested and cheerful. The tracker chooses the moment when the body is physically ready to Wake up — when increased heartbeat and the first movements after 5 complete sleep cycles. If a person needs to Wake up at a certain time, the smart alarm allows you to specify a time range during which the tracker will choose the optimal moment for awakening.
Separate the sensors for the sleep tracker to record information about the conditions in which a sleeping person, namely the room temperature and the percentage of carbon dioxide. In addition, thanks to record sensor tracker receives information about the presence or absence of snoring and a night of delirium, which also help to determine the quality of sleep.
the First pedometer was invented by the French mathematician Jean Fernely in 1525.
Monitor — a device for monitoring heart rate in real time.