And unlike Amazon, Fitbit is actually a trusted name in this space, with the new sensors on the Sense вЂ“ whatever their accuracy and usefulness in the short-term вЂ“ making it the most likely serious rival to Apple's ever-expanding health ecosystem. As with Fitbit Premium, there's a subscription service attached.ДЇitbit's $2.1 billon acquisition by Google is under scrutiny in both the US and the EU for at least the rest of 2020 Google has already pledged not to use Fitbit user health data in advertising. The invite-only Amazon Halo, a health band with no screen, appears to be leveraging years of work by Amazon's Alexa teams to offer emotion tracking via voice detection, even though the voice assistant isn't actually part of the feature set. Smaller scale experiments aside, the Fitbit Sense isn't even the only mainstream emotion detecting device launched this week. Over the next six months, the priority will be feeding in all the new data from these new sensors then over the course of 12 to 36 months, Fitbit will 'start to leverage all that data and produce new things on top of that.' The integration of stress indicators with activity, sleep and nutrition seems further off. The Fitbit app will prompt users with 'try this' triggers related to mindfulness and breathing practices вЂ“ already a feature on the Apple Watch вЂ“ and, as in the early days of slightly gimmicky heart rate monitoring testing, Fitbit will encourage users to 'go watch a scary movie' and spot check their EDA response to try to make the feature more approachable. 'We're not saying if it's a good disturbance or a bad disturbance, it's just a disturbance.' 'What we're trying to show, when people are doing this mindful meditation is what is their level of disturbance and how are they measuring that over time?' he says. We never want you to say that because we think we can get you to a good place, even without you consciously admitting it.'ДЇriedman thinks one of most useful features will be measuring 'disturbances' during guided mindfulness sessions (either short bursts or up to 60 minutes) over time. You might have cortisol, all the things that show stress, but if you don't feel stressed you're going to say this is a bunch of junk. 'So we want to be very careful about how definitively we say 'you're stressed'. 'Part of what you see in the 'may' is also around how people falsify, what do people think about with their 'aware' brain versus their more 'animal' brain and what happens when they disconnect, most people are going to trust this 'aware' brain,' says Friedman. In language familiar to anyone buying health and fitness wearables over the past five years, Fitbit carefully used the word 'may' during its virtual briefing on Sense, as in 'EDA activity may indicate your body's response to stress'.

The team is aiming for a cross-cultural, global scale which will present further challenges such as how ideas like 'health' and 'stress' are internalised around the world.ДЄnother question, that was much discussed with the introduction of Fitbit's detailed sleep tracking features, is how much people actually want to be told what their body is experiencing. Which is best for you?ДЇitbit is, he says, 'on a population level' right now with the scale of its stress tracking datasets, which aim to factor in differences in the levels of sweat people produce. Read more: The best Fitbits to buy in 2021. 'We're then gathering physiological data and merging that together,' says Friedman. In 2017, Fitbit Labs built a mood logging app that was designed to correlate how the amount of sleep changed people's moods: 'that was our first public foray into this.' Fitbit has also been conducting longitudinal studies, looking at healthy and unhealthy populations, sending out, for example, the PHQ-9 Depression Test Questionnaire. 'If GSR is combined with other physiological measurements such as skin temperature or HRV, then it is feasible to distinguish reliably a negative from the positive response,' says Kyriakou, provided Fitbit has built an accurate algorithm, that is.ДЇitbit's first experiments around stress were around four years ago, says Friedman.

That's where its algorithms come in, what Fitbit's stress tracking will in truth live or die on, but the company does have some assistance from the other sensors on board.Д«oth HRV and skin temperature can be sensitive indicators of stress вЂ“ skin temperature decreases in cases of stressful events from an average of 32 to 35в—¦C.

'Unfortunately happy stress responses like 'I just got engaged' and the really negative stress responses like 'I'm watching a really terrifying movie' can actually generate similar physiological reactions,' says Friedman.

Galvanic skin response sensor wearable