Fitness trackers have gained a lot popularity. The trend was started by the Fitbit. It has now become very common to see people wearing these fitness trackers. How do they measure sleep? This is a question that is often asked by many people. This blog post is most likely to clear all your doubts about how a fitness tracker measures sleep.

Working of A Fitness Tracker

Most modern fitness trackers are worn on the wrist instead of a wristwatch. The sensors on the trackers account for all their input, which is then transferred to a smartphone when your fitness tracker and smartphone are synced together.

One particular feature of the tracker software is that it uses complex algorithms to sort through the collected data and then produce useful information for the individual which will make even more sense once they view their history. The individual’s heart rate, as well as his sleep patterns, can easily be tracked.

How Does A Tracker Know When You Are Asleep?

Wearable fitness trackers normally come equipped with a “Sleep Mode” function to ensure that the data they’re collecting can be compiled accurately. If the user doesn’t turn it on, though, then the data collected may not be accurate and will be measured as usual no matter the user is awake or moving around.

The method which is used to measure speed and direction of your motion when you are asleep by using accelerometer is known as actigraphy. Actigraphy has been established by the American Academy of Sleep Medicine in 1995 as a useful research tool, but clinical usefulness was uncertain.  Nowadays more and more therapists use actigraphy to help people suffering from sleep disorders. For those who need help with keeping track of their wakeful and sleep times during a night, actigraphy is an easy way to do this. We also have a detailed guide on how do fitness trackers measure steps.

Actigraphy: Explained

Actigraphy allows the three axis accelerometer on the wearable fitness tracker to record all of your movements Either the movements are big or small. The gyroscope may also provide some extra information if the fitness comes equipped with it. Professionals have established certain conditions for sleep, and specialized algorithms program these movements recorded by the tracker based on these sleep data.

Actigraphy is used to collect data regarding the multiple sleep latency test. It is used in the evaluation of the circadian rhythm sleep disorders and dementia based on its ability to document restlessness by measuring motor activity. You can use it to gain valuable information about sleep during one’s natural environment versus the statistics that are typically reported in controlled studies done in a lab (i.e.: polysomnography). Despite this fact, actigraphy still does not offer adequate amounts of data for your research question due to its chance for error.

Accuracy Of Sleep Tracking

Fitness trackers that utilize actigraphy to record the movements of users cannot accurately determine quality of sleep. Actigraphy is not a completely reliable type of monitoring, since a user’s movements are counted and analyzed in order to estimate if a person is indeed asleep or awake during a night. But, the problem with this method comes from the fact that each individual may move differently when they are resting than when they are active. Because of this, almost any wearable fitness tracker that uses actigraphy has some sort of margin for error in how data is collected, stored and interpreted by each individual product.