Stress, sleep … your connected watch probably tells you anything

One French in 5 has already worn a connected watch (INSEE figure) in 2025. Similarly, An already impressive figure, but which continues to grow. Furthermore, Far from being a useless gadget, connected watches have become an essential tech object for millions of people.

Many use it to follow their physical activities. Meanwhile, Others like a “health companion”. Meanwhile, Modern connected watches allow you to keep up with the heart rate, but also to calculate sleep scores … Therefore, or stress. For example, It is precisely the latter that interests us today.

According to a recent study. Moreover, conducted by scientists from the Dutch University of Leiden, published in the Journal of Psychopathology and Clinical Science, connected watches are very bad for detecting stress. To achieve such a conclusion. they studied the data of 800 young adults, all using the same connected stress, sleep … your connected watch: a Vivoactive Garmin 4.

They compared the data collected by the watch with the observations made by the patients themselves. According to Professor Eiko Fried, principal author of the study, The correlation between these two data was “essentially zero”.

Incomplete data – Stress, sleep … your connected

Scientists are not really surprised by these results. Connected watches calculate stress scores, fatigue from very incomplete data. They use heart rate as well as user movements as a base. But other information is to be taken into account. Contextual data, known to the user, but not the watch.

Scientists explain that a sudden excitement can raise the heart rate (sex is the stress, sleep … your connected best example). The watch will take these signals for stressbut it is quite the opposite in this specific case.

A good sleep score

By pushing the study a little further. the researchers realized that the Garmin Vivoactive 4 watch was better to calculate the “body battery score”, your energy level in a way. Additionally, The figures were always inaccurate, but they followed a certain logic in all the patients.

Finally, it was on the sleep scores that the watch was the most efficient. She was able to detect the good hours of falling asleep and awakening, almost every time. It can also make the difference between a restorative night. and a bad night, regardless of the duration of the latter.

And the others?

If this study focused on how the Garmin Vivoactive 4. can the results serve as a conclusion for the entire connected watches market? We would tend to stress, sleep … your connected answer: yes … but no. Yes because the Vivoactive 4 Garmin is a good connected watch, capable of providing a mountain of data.

Its conception is based on years of research and development. In addition, Garmin is recognized as one of the best manufacturers of connected watches. But at the same time. it is impossible to draw the slightest conclusion for an Apple Watch or any other connected watch.

They all rest on their own algorithm and process all the data in a different way. The conclusions of this study are only valid for the Garmin Vivoactive 4. This does not mean that others are doing better, or that they are doing less well. Ideally it would be necessary to conduct the same study but with another connected watch to draw conclusions on. other models.

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