How Do Sleep Tracking Applications And Devices Work?




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How do sleep tracking applications and devices work and how accurate are they? what is pulse OS and what are the best fitness trackers with Oximeter?

Sleeping is an essential part of human life. We almost spend a third of our life sleeping, but good quality sleep is necessary in order to be healthy and energetic.

Lack of sleep causes depression, stress and affects our memory tremendously. So it’s natural to be curious whether your mind and body are getting enough sleep without any disruption or you are facing a sleeping disorder.

How do sleep tracking applications and devices work

In the early days, people used to keep sleeping track through traditional ways, for example, asking your partner about your sleep, keeping a diary to record sleeping hours, or recording your sleep yourself. These methods may work to calculate sleeping hours but they will surely fail in determining the quality of the sleep. Hence, the increasing awareness of the importance of sleep led to a new invention, called Sleep Tracking Applications and Devices. These personal sleep trackers are designed to accurately access sleep and its patterns. There are numerously sleep tracking applications and devices available in the market, and they all claim to track different sleeping cycles and how much time you spend in each cycle. But do these trackers work? Let’s understand them one by one.

How Do Sleep Tracking Applications And Devices Work?

There are multiple kinds of sleep tracking devices. Some of them are wearable, either you strap them around your wrist like a band or watch or you wear them like a necklace around your neck. Whereas others are Non-wearable sleeping trackers. You can keep them on your mattress or the nightstand table beside your bed. These non-wearable devices also include applications that you can download on your phone. These devices measure various factors on which they conclude whether a person is getting sufficient sleep or not. These factors include:

Body Movement

The most element which helps these devices track sleep is our body movement because when we are asleep our body becomes relatively still and we make fewer movements. We do change positions and twitch while dreaming but we are generally very calm during our sleep. These body movements can be tracked either through Actigraphy or through Accelerometer. The wearable devices use Actigraphy, in which the device contains a sensor that we wear around our wrist. While the non-wearable devices use accelerometer where you need to keep the device or your smartphone closer to you so that it can easily sense the movement and indicate whether you are asleep or awake.


Moreover, these tracking devices also use the microphone to catch or record noises. These noises may come from your body in different forms like snoring, gasping, choking, etc. The microphone can also detect the noises coming from the surrounding, for example, the sound of the TV or continuous beeping of the cellphone. The presence of these noises measures the quality of your sleep.

Heart Rate

Another important factor which enables these devices to track our sleep is the heart rate. There are multiple stages which a person goes through during their sleep. In the first stage, the sleep is light and a person can easily wake up, this stage lasts only a few minutes. During the second stage, your brain waves begin to slow down as well as your heart rate decreases. In the third and fourth stage, you begin to move into a deeper sleep that’s harder to wake up from. In this stage, your body grows and repairs itself and boosts immune function. In the final stage which is called Rapid eye movement (REM), your brain becomes more active and dreams occur. Your brain starts to process information. In this stage your heart rate increases. The wearable sleep tracking devices use HRM technology. The heart rate monitor (HRM) is attached to the skin through a sensor. On the other hand, the non-wearable mattress sleep trackers use BCG. The ballistocardiography (BCG) measure the heart rate by observing the body motion. The mattress strip includes a BCG sensor which sends a signal to the device in case of any body movement.

Body Temperature

Some of the sleep trackers also include a thermostat to measure the room temperature. The temperature has a direct effect on the quality of the sleep. The ideal temperature to sleep in is around 16-20 centigrade. If the thermostat identifies the temperature outside of this range the tracking device will automatically suggest us to adjust the temperature. 

oxygen saturation in the blood – Oximeter

Some new watches are able to measure the oxygen saturation in the blood using a special sensor combined with an algorithm(Oximeter).
This data along with the pulse measurement can help a lot with detecting sleep apnea.

A video demonstration of how To use Fitbit’s app to track your sleep

Through all of the above factors, sleep tracking devices analyze the following:

  • Sleep Duration: once you become inactive the device will start tracking the time you fall asleep till the time you wake up in the morning.    
  • Sleep Quality: movements during sleep will be recorded in order to conclude whether your sleep was interrupted or not.
  • How much time spent in each stage of Sleep: some tracking devices tend to track the sleeping phases and the time you spend in each stage. In this way, they schedule the alarm to go off when you are not deeply asleep or in the phase of light sleep.
  • Sleep Environment: the bedroom you sleep in has a huge impact on the quality of your sleep. These devices track the temperature of the environment you are sleeping and the amount of light the room has.
  • Physical or lifestyle factors: these devices also require you to put in some information about your daily life, such as, how much exercise you have done today, when did you have your last meal before sleeping, how much caffeine did you take today, is your stress level high today and many more. By calculating all of these they tend to analyze how your daily life may affect your sleep.
  • Oxygen saturation: some devices are able to measure oxygen saturation in the blood in a very accurate way, this data can help to detect sleep apnea

On the basis of these calculations, the Sleep Tracking Devices and Applications conclude and recommend whether a person is getting good quality sleep or they should improve their sleeping pattern.

Are these Sleep tracking devices really accurate?

These sleep tracking devices may benefit you in terms of identifying your sleeping patterns. Suppose a person feels inactive during a day or becomes stressful, and the person identifies that it is caused by the lack of sleep.

The device in such conditions can point out factors through which he was not able to sleep last night, for example having too much caffeine after lunchtime, or sleeping at 9 p.m. and waking up at 5 a.m. instead of sleeping at 11 p.m. and waking up at 7 a.m.

Also, through these devices, a person can calculate the amount of sleep he is getting on a daily basis.

Above all else, a person who has been to a sleeping lab may know that sleeping in a bed that’s not actually your own or in an uncomfortable environment gives you an unpleasant feeling, as compared to wearing a device and sleeping privately into your own room.

Hence, we can say that these devices may work for a healthy person who just has to identify his sleeping patterns and get some insight into his sleeping routine.

If the sleep tracker helps a person to stick to his sleep schedule and get more sleep then it the best device to invest your money in.

Can fitness trackers detect sleep apnea?

Smart watches can be used to identify almost accurate hypertension and sleep apnea, according to a collaborative study in 2017 between the Cardiogram health start-up and the University of California, San Francisco (UCSF).

The results of the study indicate that Apple’s watch and other watches, such as Fitbit’s, can accurately identify common but serious health problems. The Apple Watch used for the experiments was able to detect an abnormal heart rate of up to 97% and sleep apnea with 90% accuracy. Similarly, hypertension was detected by the Smartwatch at 82% accuracy, according to TechCrunch.

The study involved 6,115 people who used the Cardiogram application in their Apple smartwatches for a period of time.

Sleep apnea was diagnosed with 1,016 participants and hypertension in 2,230 patients.

The data collected from Apple’s watches was interpreted by DeepHeart’s deep neural network, which identified hypertension and apnea.

The results suggest a new way to diagnose serious health problems in people who may not be aware that they have these symptoms.

Even though this study’s results look promising, in cases that a person is going through a sleeping disorder like insomnia or sleep apnea, lots of these devices may not come handy.

Many studies suggest that the quality of the sleep these devices measure cannot be accurate because these devices tend to use only basic information like your sleeping hours or how many times you wake up in the night.

For example, a person with sleeping apnea may stop breathing 200 times at night but this will not be detected by the tracking devices and applications because the person might be staying still for a relatively long time.

For these cases, a pulse Oximetry sensor(Oximeter) might be helpful, since it can detect the level of the oxygen saturation in the blood while sleeping.

Best Fitness Tracker With Oximeter

The big names in the fitness trackers industry are already incorporating built-in Oximeter sensors that can measure the oxygen levels in the blood.

Popular watches like Garmin’s Vivosmart 4, Fitbit Ionic and maybe the most tested one in the field – the Apple watch 4 are able to accurately measure the blood’s oxygen levels.

Here is a short list of some of the best fitness trackers with Oximeter available on the market today.
I have added links to the relevant Amazon page where you can check them out.

The studies usually suggest a person with a sleeping disorder prefer sleep labs instead of relying on these gadgets.

In a sleep lab, sleep technicians will look at your brainwaves, along with other vital functions, such as your heart rate, oxygen levels, body, and eye movement and breathing, to monitor your sleep and diagnose a sleep disorder.

As time is passing by, the tracking devices and applications are introducing more features to improve their accuracy.

For example the movement of your eye and how often you stop breathing and for how long. If the devices are able to introduce these feature, then the trackers will be able to be more helpful for people with sleeping disorders.


Lots of activity and fitness trackers in the market offer a sleep tracking feature.
This feature can help a lot by giving you very important insights and information regarding your sleep and sleeping patterns.

However, if you are suffering from a real sleeping disorder like insomnia or sleep apnea, some devices are able to detect it in a very accurate way but you shouldn’t count on them and it is recommended to check it with professionals in a sleep lab.

Like I have mentioned, there are lots of good activity trackers that offer a pretty accurate sleep tracker, check them out here on my article on the top 10 fitness trackers for sleep monitoring.

If you want to know more about the best fitness trackers for blood pressure monitoring than here is an article that you got to read.

I hope that I helped you with the question of how do sleep tracking applications and devices work!

If you have any comments or something to add, please feel free to share it with us in the comments below.

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