Why do we need to track stress levels on our wrists?


Much more than just tracking how many steps you’ve taken or how many calories you’ve burned, the best fitness trackers have adapted to give us insight into our overall health. However, a relatively new metric for trackers and watches to monitor is stress.

Between the pandemic, the rising cost of food and gas, and even existential threats to the planet, it’s no wonder people are feeling the effects of stress more than ever. A survey conducted by the American Psychological Association (APA) in 2020 concluded that Americans face a national mental health crisis, following the impact of the Covid-19 pandemic. The report also highlighted the long-term consequences of high stress, especially on younger generations.

Continuous exposure to stress has been proven to have negative effects on your physical and mental health. Stress has been linked to mental health issues, including depression, anxiety, and sleep problems, but also to serious physical effects, such as an increased risk of heart attack, stroke, stroke, high blood pressure and weight gain. But how can wearing a fitness tracker help?

To learn more about how the best Fitbits measure stress, and why it even matters on a daily basis, we sat down to chat with Fitbit co-founder and CTO Eric Friedman.

Why should Fitbit users monitor stress?

People think stress is bad, but there’s actually a lot of good stress out there.

Eric Friedman, Fitbit

“I think stress is really interesting, also misunderstood. People think stress is bad, but there’s actually a lot of good stress. For example, if you’re running really hard in a race, it puts a lot of pressure on your body. Or, for example, if we look at the physiological reactions your body tends to undergo when someone sings you a happy birthday song or when you ride a roller coaster, both actually present events really stressful, but don’t have the same long-term physiological effect of other types of things, whether it’s a war zone or constant frustration at work.

“One of the things I learned from Fitbit was part of the anatomy of the body. Obviously the nervous system is an electrical system. You have a chemical system, all the chemical balances. You have various electromechanical systems of muscles. And so your biggest nerve in the human body is your vagus nerve and it’s on your heart. That means we can actually look for electrical interference in that nervous system to understand your body. And that’s in does what we do through heart rate variability (HRV) and some of these other metrics, so I think stress is really important.

a photo of eric friedman

(Image credit: Getty/Kimberly White/Stringer)

Why did you decide to add the stress management score to Fitbit devices?

“Our journey through stress and into stress score really happened when we started working on heart rate. People might not know this, but when we start working on heart rate at wrist, most people including investors, Fitbit people and others told us that was the dumbest idea. Either you want a fingertip heart rate that’s super accurate, when you’re in a coma motionless, or you want a chest wrap that’s super precise when running. But who cares about heart rate all day?

“We started with heart rate, exercise heart rate, sleep heart rate, and then we measured HRV about five to seven years ago with Charge 2, and found the scores were a very useful way to get people into data. We started with the sleep score, now the stress score and some of the other scores we have, and we found that some people really liked looking at all these graphs, seeing the correlation, figuring things out themselves, but d others just preferred to see a simple number — I think the scores make it motivating.

“As we start to bring together more and more sensors, we are also looking at how they relate and interact with each other”

Eric Friedman, Fitbit

“A lot of our scoring systems come from our behavior change groups on the research team. People go to the doctor and the doctor says, ‘You need to lose weight or quit smoking’. You go at the dentist, “Hey, you need to floss more or brush your teeth differently. And people are just good at ignoring that kind of information. People often don’t like bad news, so how getting them the right message? We believe it’s by helping them dive into data. As an engineer and researcher, data is great and it’s data that will drive behavior change. Ultimately , as a product company, we try to help people live healthier lives, and if we don’t change someone’s life, there’s no point in doing so.

You talk about users learning from data over time, what have you learned from Fitbit data and in particular stress scores during the coronavirus pandemic?

“One of the things I found most interesting was that when people started going through lockdown, their resting heart rate went down, not up. So they were very stressed and they were doing less of exercise, but their resting heart rate was dropping.When we started trying to really unbox it, we found that people actually slept more consistently.

“One of the things I found most interesting was that when people started going through lockdown, their resting heart rate went down, not up.”

Eric Friedman, Fitbit

“Often people have one set of bedtimes Monday through Friday and a different set Saturday and Sunday. It’s called social jet lag. It’s like flying from New York to the California – you often don’t feel very well after getting off that flight for a few days. And so we actually found that people’s resting heart rates go down because they sleep better. And that ties into this whole idea that there’s stress, both emotional and physical, there’s exercise, there’s sleep, there’s the way you eat, and it’s all connected. or ignore everything else, you’ll often find that you’re not actually driving the right health outcome.

In 2020, you added EDA scanners to Fitbit wearables for the first time – why?

“I think EDA, just like heart rate, is a new sensor and I think there’s a lot of interesting value in there. The value comes from two things – one is the improvement of the algorithms in addition to the data and the second is that users use it for longer periods of time we can give people better context of what’s going on, especially with something like EDA stress, where there’s all kinds of confounding factors that can get in the way It’s on Fitbit to help users unlock value by showing seasonality, cycles, all sorts of other fitness types, that confuse and alter these signals.

What do you think Fitbit is doing that your competitors aren’t in this space, both in terms of tracking, stress and development?

“I think we’re in a unique position right now, with both a stress and heart rate monitor, but I don’t think we can rest on our laurels. Imitation is the sincerest form of flattery and we’ve been highly flattered for the past eight years or so. The next step is how we continue to add value, both for the people who buy the next-gen device, but also for the people who stick to their current device.

“We have just conducted one of the largest clinical trials in the world for atrial fibrillation and it is using HRV for an analysis of disease status. It’s been cleared by the FDA and it can be rolled out to many new and existing devices, so I think that’s also very exciting.

Where do you see things going next? What do you think is the next thing we are going to put on our wrists?

“I’m still excited about our next sensor, but what excites me even more is the sensor fusion aspect. As we start to bring together more and more sensors, we’re also looking at how they relate and interact with each other. I think that’s a really powerful thing. You see temperature, your heart rate, and your movements combine to fuel sleep. You see HRV, various movements, other things that fuel the activity and how you behave in your stress work. Things like that are really the future, like how do you merge those things together.


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