Transcript

Rachid Finge 00:00:02 Welcome back to the Made by Google Podcast. I'm your host, Rachid Finge, and today we're taking a look at one of the most impressive features of Fitbit. Fitbit is, of course, known for tracking your activity, workouts, heart rates, sleep, but Fitbit also has a long history in managing stress. Today we're talking about one of the most impressive stress managing features that Fitbit has to offer. It's called Body Response. We're joined today by a great team of people who can tell us all about the body response feature, what it is, how it works, and how it can help you live a more mindful life. So let me introduce you to our guests group product manager, Elena Perez. Samy Abdel-Ghaffar, who's a senior research scientist, and Isaac Galatzer-Levy, a senior staff research scientist. Elena, Samy, Isaac, welcome to the Made by Google Podcast. Great to have you. Let's get to know you a little bit more. Elena, I'll start with you. Sure.

Elena Perez 00:00:59 Uh, in short, I've been at Fitbit for almost four years, and got here actually through more of a medical device background, but have been working on our wellbeing experiences since coming to Fitbit.

Rachid Finge 00:01:13 Amazing. Great to have you. Samy, what about you?

Samy Abdel-Ghaffar 00:01:16 Hi, Rachid. Thanks for having me today. Uh, so I've had somewhat of a winding career trajectory. I started off as a software engineer. After doing that for a number of years, I looked for something a little more interesting and aligned with my personal interests. And I did a PhD in cognitive neuroscience, studying the brain basis of emotion and using machine learning to apply to brain scans to infer things about the emotional brain. And I've been with Fitbit now for four years. I'm a senior research scientist specializing in stress and mental wellbeing.

Rachid Finge 00:01:47 Thank you, Samy. And last, but certainly not least, Isaac.

Isaac Galatzer-Levy 00:01:50 Hi, Rachid. It's nice to meet you. I'm a senior staff research scientist here at Google, and I've been here a little bit under a year. My background is in clinical psychology and neuroscience, and what I do here at Google is really focused on how we use mobile sensing to measure mental health and, psychological related functioning.

Rachid Finge 00:02:10 Today's guests work on Fitbit's wellbeing features. Elena Perez is a group product manager who joined Fitbit in 2019. Today she works in all sorts of wellbeing features that Fitbit is famous for, from sleep and nutrition to mental health. Samy Abdel-Ghaffar joined Fitbit around the same time as Elena, and combined a bachelor's degree in computer science with a PhD in cognitive neuroscience. And Isaac Galatzer-Levy joined Google about a year ago. Isaac has a PhD in clinical psychology, just like Samy. He's a senior research scientist, and they both explore ways in which Fitbit can aid in mental wellbeing. I hope you'll enjoy our conversation. Okay. So we're here to talk about body response on Fitbit Sense 2, but how would you explain what a body response is? Elena?

Elena Perez 00:03:03 Great question. So the body response feature launched with Sense 2 last year. And the experience really is meant to be a holistic experience where it not only is on throughout the day to prompt you at specific moments where we may detect these body responses. That could be stress, could be excitement, could be something like a stimulant like coffee. And the whole idea is that we wanna allow you to take the moment to reflect on what's going on. And if you are having a stressful event, we give you interventions that you could do to potentially tackle them, whether it's in the moment, or you could at any time go through and look at what are the options Fitbit offers,

Rachid Finge 00:03:47 If my Fitbit Sense to gives me a body response notification, then what did it measure? Like, why did it prompt me?

Samy Abdel-Ghaffar 00:03:55 There are actually many different sources of physiological changes that all look very similar. You may have heard of something called the fight or flight response. Mm-hmm. . So scientists call that sympathetic nervous system arousal, which is a lot of big words to mean: You have a unified system that gets activated under a number of different circumstances. And so when that fight or flight system is activated, you see pretty stereotypical changes. Your heart rate rises, you start to sweat a little bit more on your, your pumps, your hands and back of your wrist. Your skin temperature drops a little bit, your heart rate variability drops. And so all of these things give us a physiological signal that something is happening. So scientists would say it's a very sensitive measure that something is happening, but it's not very specific things like riding a rollercoaster and having a car accident, even though one is positive and one is negative, at least for most people, the rollercoaster is positive, right?

Samy Abdel-Ghaffar 00:04:59 , your body is gonna respond in a very similar way, same with drinking alcohol or caffeine. And there's a lot of different scenarios that can cause this. And so we didn't want to over-index on the fact that it could just be stress. We thought that might mislead users and lead to a poor experience. And so we decided to come with something that is more neutral in what it's claiming. Basically, we're saying something is changing in your body, now you have the opportunity to reflect on it, which really is a golden opportunity because it's not simply just that the environment causes stress. When you feel stressed or you have a stress response, it's because you, your brain, your mind have appraised the situation as stressful. So if you can have the opportunity to really reflect on, you know, what was I thinking? What meaning did I just make of that situation that caused me to have stress? Whether it's a social interaction or, or something more physical like a car accident, it can really allow you to change both long-term in terms of how you learn to appraise things differently when you, when you have that moment of awareness, that opportunity to reflect. But it can also give you a chance, like if you're just feeling really stressed in the moment, maybe you just need to step away and go do a walk or a meditation or a guided breathing session.

Rachid Finge 00:06:22 Yeah. Because when I get that notification, I can sort of log the emotion that I was feeling. What can I learn from that? And, and how would that, I guess, improve my wellbeing if I log those long enough, what, what can I learn from it?

Isaac Galatzer-Levy 00:06:35 If I could put on my clinical psychologist hat here, I would say that most people are not very good at monitoring their own physiology and understanding how it affects you. So a very simple example is if you've ever had a disagreement with a significant other and you say, I'm not angry. You know, we're just not very good at monitoring that, especially in the moment. So the ability to give that feedback to people actually helps them to learn how to modulate it, understand what's physiology versus what they really think and feel and start to separate that and have more productive conversations. So in that scenario, knowing allows me to say, my blood's a little hot. You know, my heart is racing. Let me take a moment to take a deep breath, and then I have a more productive interaction and I learn something about myself. So that's really that idea of just giving people that insight is of enormous value to just understanding yourself and understanding, you know, how your biology affects you in day-to-day life.

Rachid Finge 00:07:35 It also sounds like a pretty complicated thing to build because you sort of need all those sensors on such a small thing, like a Fitbit Sense 2 to measure these things. So I always notice, I see some green and red lights on the bottom of the device. So what are the sensors at work to even get the body response feature working?

Samy Abdel-Ghaffar 00:07:52 Yeah, so the body response algorithm actually uses a number of different sensors. Those little lights that you measured are called photo flexography or P P G. And from that we can infer both your heart rate mm-hmm. and your heart rate variability, which is how much is your heart rate changing from beat to beat over the course of several minutes. And that's been associated with all sorts of things, including sympathetic nervous system, arousal, or fight or flight activity. And so in addition to the P P G sensor, the sensor 2 also has the electrodermal activity sensor, which we mentioned before, which it's really measuring the electrical conductance across your skin. And so you might know that water is really conductive, so when you sweat, even if it's just a little bit, it changes the amount of conductivity across your skin between two electrodes on the back of the device.

Samy Abdel-Ghaffar 00:08:41 And so that's another signal going into it. We also have a skin temperature sensor on the back of the device. And then for some really interesting sort of edge cases, we might say, or times when we don't think we can really trust what the device is telling us, that physiology, and we use several other sensors. So there's, there's an accelerometer and a gyroscope, and both of those things can help us infer what you might be doing, are you exercising? There's also a barometer, which helps us infer pressure. So when water is covering that, it shows a change in signal. And so, uh, as you might imagine, because what we're really measuring is changes in, in water on your wrist, if you put the device underneath water, it's gonna cause it's gonna look like a huge sweat, a signal just changed. But we can infer that fortunately. And so we can just disable the device during those moments. Or when you're exercising, the physiological changes look very similar. Your heart goes up, you start sweating more. And so we don't want to be giving people false positives saying, Hey, you're having a body response when it's really just from exercise or because you wash your hands.

Rachid Finge 00:09:50 So you have all these sensors that are coming together, but then at some point you need to, I guess, teach the system. When is it a body response? When is it not a body response? So how do you create that algorithm and how do you sort of, well teach the system what's what?

Elena Perez 00:10:06 I'd say that when we looked at the experience, we wanted to be able to test with gold standard and standard methods that are tested in science and in clinical practice that are trusted to be able to build the algorithm. And at the same time as we thought about the experience, we wanted to, as Samy mentioned, pull out those cases where we know there may be a response, whether you're working out or during sleep. We wanted it to really be relevant to the user at the best times and take out those times where it wasn't gonna be relevant. And all of that experience went into it. We also did a lot of user testing as far as perception. Mm-hmm. , both as Tammy mentioned on the name, because we wanted to be able to assess that there wasn't a negative connotation. We don't want this to be feeling judgmental or negative. We want to allow users to know that stress happens and we're not intending to say that we're removing stress. What we're hoping to do is provide increased awareness and allow the user to gain that reflection on what is happening, what are the trends that we're seeing, when is the user feeling that stress, and what are the things that are gonna help them address it.

Rachid Finge 00:11:21 You mentioned the user testing. Could you tell us a little bit more about how you sort of test that feature? So what, what do you tell the users that are testing it and what do they do to make body response work?

Elena Perez 00:11:33 We did a lot of user testing on the experience itself and how users perceived a notification, whether they wanted a notification or not, and also what the right timing would be to deliver. And some of the things that we heard were that not everybody wants the notification in the moment. Some people wanna be able to reflect on their own time. So we made that an option. We gave the user full control of whether they wanted those smart notifications to be on or off. Uh, but Samy can talk a lot in a lot more detail about how we actually built and tested the algorithm itself.

Samy Abdel-Ghaffar 00:12:06 So we started the project by exploring the literature, and there's a procedure called the Tri Social Stress Test, which is considered sort of the gold standard for social evaluative stress. What that means is we all know if we're giving a public talk or we're in a situation where other people that we care about might be judging us, that can be a very stressful thing. And so we decided to use the Trier Social Stress test, or T S S T to induce in a lab environment a stress response. So first you, there's just a baseline period, and then you're told what is gonna happen. You're gonna have a dream job interview, and you have five minutes to prepare an argument for why you deserve your dream job. Then at the end of those five minutes, we very cruelly take the notes that you just created and delete them. So that's the first stressor. Then you're sitting in front of a panel of three people and you're asked to just keep talking, and they have pretty stony faces that betray no emotion. At the end of that, you have a surprise math test where you're told to count down from some huge prime number by 13, and every time you get it wrong, you're asked to start over.

Rachid Finge 00:13:25 I might get a body response notification very shortly just from listening to this story, .

Samy Abdel-Ghaffar 00:13:31 Yeah, exactly. So we use those data, we pre-process them. We did a lot of transformation of those data, and then we used a classical machine learning algorithm to identify the patterns in those during which people were showing an acute stress response. We also collected some, what we call free living data, where people were wearing the device in their lives over the course of a week. And at various times from a physiological change, or sometimes just randomly, we asked people to tell us how they were feeling, how stressed were they on a one to five scale. And so we use that data to validate whether the algorithm that we collected in the lab was actually able to capture these stress events that happened out in the wild.

Rachid Finge 00:14:15 So this is maybe slightly more personal, but I have the experience where I sometimes get that notification. I'm like, but nothing happened. I think, is that a maybe also a prompt and that I maybe should learn more about myself? Could it be a false positive? What should I learn from these kinds of notifications where I have absolutely no clue what, what changed?

Samy Abdel-Ghaffar 00:14:38 Yeah, that's a good question. So with something like heart rate, it's fairly easy to get a nice ground truth of what are we actually looking for with stress? It's a lot harder. And that's for, for a number of reasons. One is that you might feel stressed, but not really have a physiological response happening in the moment. Mm-hmm. , another reason is you might have a physiological response in the moment, but it's either due to something else that isn't really about how you're feeling, or you might not just be aware of it. Emotional awareness, emotional intelligence is something that varies pretty drastically both across people and within a person during a day. You know, emotional awareness is really about attention. How much attention are you paying to your feelings? And so your body might be doing something, but your attention is focused on the game, or, you know, a conversation that you're having or work or, or your child or something else where, you know, you might think nothing's going on, but it actually is.

Samy Abdel-Ghaffar 00:15:44 And so I think that is potentially one of the most exciting things that a body response can give you is like, Hey, why don't you take a second to think back about what just happened? It may be the case that you don't recognize that anything was going on. And certainly there are false positives. I don't think any of us are claiming this is a perfect algorithm. It's a really hard problem to solve, but the fact that you're not immediately aware of some sort of feeling to me isn't necessarily a problem. It's an opportunity.

Isaac Galatzer-Levy 00:16:19 Rachid, I was gonna add to what Samy said. You know, I remember when I first got a sense too, and I had my first body response, actually, it was when I came onto Google and I was about to give, be part of some big presentation for the VP of my department. And I remember leading up to that, I wasn't thinking about myself at all. I was very focused on going through my slides, figuring out, making sure I'm communicating, thinking about, oh, all these new people and, you know, what are they looking for? I noticed that I got a body response and I had not realized that I was, you know, that that was so arousing for me actually that that experience. Um, and it really was helpful for me to understand, okay, going into meetings, you know, that are important, my ability to regulate myself actually helps me prepare better, be sort of clearer in my thinking. So it's sort of an opportunity to reflect back, even though I didn't have a subjective feeling, just like Samy was saying, I wasn't in the moment saying, oh, I'm so stressed. I was really just focused on my work.

Rachid Finge 00:17:20 I think that is a great point of emotional awareness and indeed an opportunity to learn something new. So that's definitely one thing I'll keep in mind when it happens again in the future. Now, when it comes to stress, I guess it's fair to say Fitbit has a rich history of, you know, measuring that and making that insightful for its users. Where does body response stand in that evolution of Fitbit's stress management?

Elena Perez 00:17:46 Elena, the first stress management experience that Fitbit launched was this stress management score. And that algorithm is different in that it's a once a day retrospective look at what your data looks like for the last day or the last week. And it's supposed to be something that the user can look at as they wake up, and it still looks at physiological aspects, including sleep and activity from the last night, yesterday and even the previous week. And the goal of that is to try to predict how your body's resilience is likely to react to stressors today. Um, it really is meant to help you plan your day. And we have a number of interventions that we also launched at the same time, mindfulness experiences, other aspects of the Fitbit experience. And again, the, the goal is to try to help users manage and learn what works best for them is, and I think what we wanted to do with the body response was provide more of that in the moment throughout the day support as well, so that it, it's not just looking at how do I plan my day and what happened yesterday, which is really important and, and helpful, but also having the opportunity to do more of that throughout the day and have that opportunity to reflect and understand what's going on with their body and what they may learn about those patterns.

Elena Perez 00:19:15 For example, you may notice that your stress or your body responses might trigger more at a certain time of the week or the month or the day. I know anecdotally for me, I would pride myself at being very productive at night, but I noticed that when I was working late was when I was getting these body responses and it really helped me understand that while I may not think about it, it really was impacting my physiology and potentially impacting my sleep and other aspects of my health as well. And so it's really about creating that awareness and helping the user use that information.

Rachid Finge 00:19:53 I know that everyone who works on a product at Google always craves feedback and we love to listen to stories from people who use our products. I'm just wondering, is there any sort of story that you remember from, from a Fitbit user who uses the body response feature that said something that I guess maybe also appreciates the work that you do and put in that body response feature?

Samy Abdel-Ghaffar 00:20:17 So I have a couple different anecdotes that come to mind. The first one is one of our, our colleagues, Isaac and my colleague on our stress team is Daniel McDuff. He's a wonderful scientist. One of the first days that he got his sense 2, it was in the morning, it was before work. Him and his wife were scrambling to get their child fed and dressed and off to childcare. And he got a body response at that moment. And he looked at it and he looked at his wife and he was able to to say like, Hey, why don't we just take a second? Just having that awareness for him brought down the level of stress, of, of pressure. I really loved hearing that, that that was his first body response. He was able to take action on it.

Samy Abdel-Ghaffar 00:21:07 And the second one feels a little like I'm bragging, but this really is my favorite media review was a review in The Verge. I liked it for two reasons. One, because it was complimentary to us. They thought we had done a great job. The author had said it was the best stress management experience out there for a consumer electronic device. But more to the point, I think she saw what we were trying to do, which is not say that we always know when you're stressed and what to do. 'cause there's no device in the world that can claim that with authority, I don't believe. But what we're really trying to do is give you, as the user the power of awareness, because awareness can both build your capacity to make meaning of the world in a way that causes you to have less stress as you start to recognize the thoughts and the meaning that you're making of the world.

Isaac Galatzer-Levy 00:22:10 Rachid, I had an interesting experience actually. Um, that's not about one individual story, but actually a really large set of individuals stories. Samy and Daniel, who Samy mentioned, and I have been analyzing data across large groups of Fitbit users, so a quarter of a million Fitbit users. And we've been looking at events like Thanksgiving or Christmas or tax day that are really stressful for all of us. And what we see in the E D A sensors is really noticeable, statistically distinct spikes in stress or in arousal and, and body responses those days. And for me, actually, that was very heartening because I think I find traveling for Thanksgiving and Christmas very stressful, and we can often feel that our stress is unique or, or it's particularly impactful, but it's nice to know that we have common experiences and that's really normal. It's sort of part of it, it doesn't even necessarily mean anything bad. Getting back to Elena's point about resilience, human beings encounter a lot of stress in their day-to-day life across their life course. And, um, just understanding it and, and learning how to manage it is really, and understanding it's not unique to us. It's just part of life is really helpful. So that was really interesting. We also saw, for instance, on New Year's Eve, people really spike and, you know, speaking of excitement, yeah.

Elena Perez 00:23:31 Just to add to that, Isaac, my favorite analysis that I've seen from the team is Super Bowl. Yeah. The fact that you can see the spike Oh, wow. In the first half, the dip during halftime and second half. It's just such a cool data set to look at, um, at a demographic level. And I'd say anecdotally, one of the ones that's really memorable for me, that isn't about a negative type of stress or what a typical stress situation might be considered as, but there was someone on the team that mentioned that one of the ones that they really remember was getting, seeing someone that they hadn't seen for years and just meeting them for lunch. And when they saw them, they had this body response and it was a really positive excitement that actually drove that one. And so again, it wasn't necessarily the type of negative stress that people typically associated with it, but it was still an accurate response that that person was having at the time. And the reflection they had was, wow, this, this really was a positive moment and it showed up physically and I wouldn't have expected that, and maybe I should do this more often. You know, what are, what are the people in my life, the things in my life that bring me this type of joy and excitement that I need to do more of? And so, again, it's a flip side of thinking about how this feature could also be used.

Rachid Finge 00:24:57 Those are amazing stories. I definitely got a whole new appreciation for, for the body response system in Fitbit. Now, before we go, we always ask our guests about their top tips for the things they're working on. Of course, it'll be very easy to say, well enable and use body response notifications, but maybe there is something that's top of mind to share maybe when it comes to Fitbit and stress management in general. What would you tell our listeners of the Made by Google Podcast, your top tip?

Isaac Galatzer-Levy 00:25:28 I would say that, you know, echoing what Samy and Elena have already said, understanding the meaning of, of those physiological response responses, understanding the context is really powerful for people. And so the direction I would love to see us headed in is to help people to better understand those relationships.

Rachid Finge 00:25:47 Elena, anything to add there?

Elena Perez 00:25:48 Yeah, the thing that I would add maybe is more on not only the detection and reflecting on what's going on, but how do you as a user understand what helps you best? And I think just as an example, we have a variety of pieces of content, whether it's mindfulness, well yoga, mindful walking. We have a variety of different content pieces that, to Samy's point, are in the mobile app and really can help the user understand if, if I am stressed or if I do need that moment to build up my resilience or take a moment to step away and reset is yoga, the thing that helps me the most is a mindful breathing exercise. What really makes me feel the best? Is it actually moving my body and going out for a walk or a run? And so I would just encourage users to try things out. And don't put pressure to do it perfectly the first time or any time. And don't put pressure on the amount of time it should be. Even two minutes could be really helpful.

Rachid Finge 00:26:56 Those are great tips. Thank you so much for joining the Made by Google podcast, Elena, Isaac, Samy, and hope to see you again in the next season.

Elena Perez 00:27:03 Thank you. Thank you very much.

Samy Abdel-Ghaffar 00:27:04 Thank you very so much.

Rachid Finge 00:27:07 I thought that was an enlightening conversation. Great to know the background behind Body Response, what it can do and what it has done for people. So if you're excited to try it out, it's available right now on Fitbit Sense 2 next time out. It's the final episode of this season of the Made by Google Podcast, and it's a special one for two reasons. First, we're talking Pixel Fold, so that's special in and of itself. But second, it's an episode with only questions from our Superfans. It's a Q&A with one of our product leads. So I definitely subscribe to the Made by Google podcast for that. Take care and talk to you soon.