How do sleep trackers work?

Digital fitness and sleep trackers are all the rage and are considered a simple tool to analyze and improve your own sleep behavior. Here we explain exactly how sleep trackers work, what values ​​are measured and whether they can really help to improve sleep.

Table of Contents

1. What are sleep trackers?
2. How do sleep trackers work?
3. What do sleep trackers measure?
4. Can sleep trackers improve sleep?
5. Conclusion

1. What are sleep trackers?

Like small digital laboratories for at home - more and more people are wearing fitness watches and sleep trackers to take a closer look at their own bodily functions and sleep patterns. Sleep trackers are mobile or permanently installed technical devices that measure and record certain bodily functions during sleep in order to evaluate them in combination with software or an app. The results should give a conclusion about the sleep behavior and help to identify irregularities or sleep problems.

2. How do sleep trackers work?

Sleep trackers usually have several sensors to measure movements and vital parameters. The exact functionality also depends on the model type of the tracker. Portable devices, so-called wearables, such as smartwatches or fitness/activity bracelets, are particularly popular. But there are also trackers that are permanently installed and integrated as a sensor pad under the mattress, for example.

Wearables such as the well-known Apple Watch or the Oura Ring are worn directly on the body and usually have a 3-axis acceleration sensor, a gyroscope and an optical sensor. They perceive movements, measure heart rate and respiration and can also determine blood flow or the oxygen saturation in our blood. This data is recorded during sleep and processed and evaluated in software or an app in order to draw conclusions about sleep behavior.

3. What exactly do sleep trackers show?

Based on the measured values,

sleep trackers can provide us with information about how long it took us to fall asleep, sleep duration, sleep cycles, sleep phases or cardiac and respiratory failures. During sleep, we go through different sleep phases in several sleep cycles, in which our body behaves in different ways. You can find out exactly how sleep works in this article. A pre-programmed algorithm should then be able to use the heart rate or the intensity of our movement to determine, for example, how much time we have spent in deep or REM sleep.

4. Can sleep trackers improve sleep?

Whether a sleep tracker can really help you to improve your sleep depends in particular on how you deal with the results of the analysis. From a scientific point of view, the heart rate, breathing and movement at night are not decisive enough to make an accurate statement about the quality and structure of sleep. While our breathing, heartbeat and physical activity change throughout the night, sleep takes place primarily in our brain and is primarily measured by changes in activity patterns in our neural networks. In sleep research, sleep behavior is therefore analyzed using brain activity, eye movement, body temperature and muscle tension in combination with bioparameters that can be measured by sleep trackers.

In addition, the measurement accuracy of the trackers can be easily influenced, for example if sensors are not correctly placed on the skin or if there are other people in bed. And even if our bodily functions and vital parameters deviate from the known "normal values" due to illness, for example, a sleep tracker cannot make a really reliable evaluation of our sleep.

Sleep trackers are practical and well suited to get a rough overview of your own sleep-wake behavior and especially the sleep duration or to point out possible irregularities in breathing. However, it is important not to rely too much on the details such as the course of the sleep phases or deep and REM sleep proportions, because the measured data do not have to correspond exactly to our actual sleep behavior. If we feel fresh and rested the next morning, we should still trust our personal feelings and not be influenced too much by a sleep score or recovery score of our sleep tracker. In combination with good sleep hygiene, the popular trackers can be quite helpful to take a closer look at our own sleeping behavior and to find out how we can improve our sleep.

Our tip: Relaxing evening routines and healthy sleep hygiene are the most important basis for ensuring a good night's sleep in the long term. With a sleep tracker you can then check what your body values ​​look like after a restful night for you and whether there are any abnormalities in your personal feeling and the measured parameters.

5. Conclusion

• Sleep trackers are wearable or fixed devices that use a variety of sensors to measure and record heart rate, movement, respiration, and other vital signs during sleep.

• Sleep trackers can provide information about the duration of falling asleep, sleep duration, sleep cycles, sleep phases or heart and respiratory failures.

• The measurement accuracy and evaluation function of sleep trackers can be easily influenced, which is why the devices are recommended as a guide, but not for reliably evaluating sleep.