A new study reveals that intelligent watches are not so good for measuring stress

Some health enthusiasts swear by smart watches as a way to monitor stress levels, but a recent study questions this current use. The study, published in the Journal of Psychopathology and Clinical Science, affirms that these watches display a very limited capacity to communicate really what the psychological state of a person is. Sometimes a watch may think that the user is stressed when he is really enthusiastic about something, say the researchers.

The report examined nearly 800 students who wore a Garmin Vivosmart 4 smartwatch and measured their self -depressed emotional states against the metrics collected by portable devices. According to the study, the self-declarations of the watch carriers and the analyzes provided by the watches looked little. He notes:

We have studied simultaneous overlap between self-assessment and portable sensor data measuring stress, fatigue and sleep. For the majority of individuals in our sample, we have found that self-assessment and physiological measures of stress show very low associations. These results raise several questions about the differences between data sources and potential measurement problems.

Garmin announces a stress monitoring capacity for his smart watches on his website. “Stress levels (0–100) are estimated by the FirstBeat Analytics engine, mainly using a combination of HR and VRC data. These data is saved by the optical cardiac frequency sensor on the back of your device. ”

However, Garmin seems to admit that the quality and character of stress can be difficult to measure: “Talking in public and raising a staircase can both send your heart to the race, but the underlying reasons why are fundamentally different,” notes his website. The company suggests that wearing the watch more frequently can cause better measures. “You can improve the quality of the information acquired by carrying your device as much as possible, especially while you sleep, because it is at this time that your stress levels will generally be the lowest,” said the site. “It helps to create a better understanding of the full range of stress and relaxation you feel.”

In an interview with The Guardian, one of the study authors, Eiko Fried, said that the correlation between self -declared stress scores that were collected as part of the study and the readings provided by smart watches were “fundamentally zero”.

“It is not a surprise for us since the watch measures the heart rate and the heart rate does not have much to do with the emotion that you feel-it also increases for sexual excitement or joyful experiences,” he told The Outlet. “The results raise important questions about what portable data can or cannot tell us about mental states,” he continued. “Be careful and do not live according to your smartwatch – these are consumption devices, not medical devices.”

The subject of the study has a history of diversified research. A meta-analysis in 2023 of studies on portable clothing and stress management revealed that “the effect of portable approaches on attenuation or reduction of stress” had “not been analyzed” and that most of the studies to this point were “concentrated on the presentation of the previews of portable devices”. Another study published by researchers from the Vrije Universiteit Amsterdam in 2023 revealed, a bit like the recent psychology study, which intelligent watches have often failed to distinguish excitement and stress. Gizmodo contacted Garmin to comment on the recent study and update this story if it responds.

Although the study says that Garmin’s Wearable did not do much to measure stress, the researchers found that it seemed to provide decent measures in other arenas. The report indicates that the watches were very good at measuring sleep, although it notes that “associations were lower for fatigue”.