Stress wearables: best devices that monitor stress and how they work

How wearables are dealing with stress for the mind and body
Stress monitoring wearables in detail
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Wearables have made big strides in monitoring how stressed we are, and the likes of Garmin, Apple, Fitbit and Google are all on board.

Stress is something we all encounter, whether it's particular situations in our lives or just a hectic day at work. But it can have an impact on our health and lives, which is why stress scores, guided breathing and mindfulness are all becoming key features.

Stress detection and coping techniques are already prevalent on wearables, and it's not just about looking after you mental wellbeing.

Wearables are also using these physiological measurements to offer an insight into the kind of stresses put on the body through exercise. That way, individuals can have a better understanding on the strain and stress you're putting on your body that could impact on future workout sessions.

So whether you care about stress tracking for the mind or the body, we break down how wearables monitor stress, the insights they offer and how the biggest companies are tackling it.

How wearables measure stress

How wearables measure stress

At the heart of how the majority of wearables monitor stress is, well, your heart. Devices such as the Apple Watch, Samsung Galaxy Watch and many of Fitbit's trackers use heart rate monitors, which offer 24/7 feedback on our bpms (beats per minute).

In more recent years, wearable makers have developed other types heart rate activity measurement that can unlock additional health and fitness insights. The one most relevant to this rise in stress monitoring is called heart rate variability.

Heart rate variability (HRV) relates to the measurement of the time interval between heartbeats. Unlike measuring heart rate, which relates to average number of heart beats per minute, these heart rate variability readings are more focused on the small fluctuations of the heart.

The key thing here is what can cause those fluctuations. These include age, body position, time of day and your current health status, but crucially, emotional, physical and mental experiences can impact on heart rate variability.

If you have a high heart rate variability, that's commonly considered a good thing. A low HRV reading I can be a sign of stress on your body. The likes of diabetes, heart disease and cholesterol are medical issues commonly associated with some having a low heart rate variability.

However, that measurement alone isn't enough to tell you whether you're stressed or not.

"It takes a lot of specialized expertise in mathematics, signal processing, pattern recognition, and programming to get to the point where you are providing useful information to people," says Herman Bonner, communication specialist at Firstbeat, who are now owned by Garmin and powers stress tracking features in its watches.

Stress and guided breathing

Stress and guided breathing

There are two main ways that those heart rate variability measurements are being used to measure or track stress. The first is related to offering an insight into people's mental wellbeing. So this is the kind of stress you experience when you've maybe got a lot on your mind.

Many wearables will use this HRV data to produce a 'stress score' from 0-100 that gives you a clear idea if you are experiencing a stressful moment in your day.

We have also seen the use of guided breathing exercises that lean on onboard heart rate monitors and HRV to help indicate when you've returned to a calmer state.

"Mindful breathing lets users take control of how they handle stress," says Han Paik, a senior product manager at Garmin.

"When we breathe in a controlled, thoughtful manner we gradually lower our heart rate and increase the beat to beat variability. When this happens, the brain gets a signal from the heart that is basically like saying 'Relax, things are okay! No need to worry.'"

"When our breathing is rapid and shallow, our heart rate gets fast, and more inflexible. That’s when the brain and the body get the opposite message which makes us stressed."

Stress for the body

Stress for the body

The other big area of stress tracking and wearables relates to fitness and exercise. So this is the concept of using the same heart rate variability measurements, to help indicate the strain and stresses put on the body after a workout and what it can mean from your recovery.

Companies like Whoop, Oura and Fitbit use those heart rate variability measurements to offer insights into how ready your body is ready to perform.

The value lies in using those measurements to understand trends that can help you see when you are at your optimum to tackle a workout.

A high HRV usually indicates that the body is in good shape, while a low HRV during activity could be an indication that you're fatigued, dehydrated, stressed or even unwell, which would impact on your ability to train and exercise.

A lot of the value people get from tracking their stress comes from looking back over their days and weeks," says Bonner. "This is a hugely different perspective from what you get from sitting down and firing up a stress test, seeing the results, and moving on to the next thing.

"At any given moment, you tend to have a pretty good sense of whether you are stressed or not. Catching trends, ups and downs when you aren’t even thinking about it can be truly eye opening."

The accuracy of stress wearables

The accuracy of stress wearables

Stress monitoring can only be great if the technology it relies on to provide those insights is reliable. In most cases, we are talking about optical heart rate monitors, which have rightfully been called into question over how accurate and reliable they really are.

If the heart rate sensor on your wearable is unable to accurately read your heart rate, can it be trusted to tell you how physically or mentally stressed you are?

Firstbeat, who provide the heart rate-based analytics that underpin Garmin's all-day stress tracking features says it's stress measurement analysis has been validated and improved over the course of decade and has been used in "over 200,000 of its Lifestyle Assessments conducted by health, fitness, and lifestyle professionals." It should be said though that those assessments use devices that are worn directly on the chest to measure HRV 24/7.

When we spoke Dr. Steven LeBoeuf from biometrics experts Valencell, a company that provides optical heart rate sensors for the likes of Bose, Jabra and Suunto, he gave us his thoughts on measuring heart rate variability, which underpins the current way of measuring stress on wearables:

"It's really difficult to deliver heart rate variability from the wrist when you have so much movement of the wrist. Our technology works best when people are not moving," said Dr. LeBoeuf.

It also told us of the value to moving heart rate tracking to other parts of the body like the ear and areas that are closer to the heart, like the chest should improve accuracy and reliability of the data. So we could well see more of wearables move around the body to improve the reliability of the data and using those insights.

The reliability of wearables' ability to track stress could improve by looking into other data that can be drawn from the body. One of those actively being explored is sweat and ingredients of your perspiration can be tapped into to measure stress hormones and offer an insight into your emotion stress.

Future of stress wearables

stress wearables draft

Sensors that already provide these stress measurements right now will continue to improve in terms of providing more accurate data but also helping users act on it. That challenge that comes from how people make sense of that says – something Bonner believes will improve.

"Your watch can recognise that you are experiencing an elevated state, but it doesn’t necessarily know why that is the case," he tells us. "The individual user still needs to bridge that gap, using their own awareness how potential stressors might affect them."

"The next stage is clearly going to be taking the stress and recovery data that wearables collect and putting it to use," adds Bonner. He points to projects that are popping up in other industries like automobile industry. That's where Mercedes recently announced a project where stress data from a Garmin watch is used to adjust various environmental controls and systems.

"You will also start to see stress tracking insights used to ground and tune personalized lifestyle and training tips," says Bonner. "Obvious opportunities exist for tuning the scheduling and strenuousness of your workouts based on things like daily stress and sleep quality."

Stress and wearables is still in its early days and what it could look like in five or ten years time is an exciting prospect.

Best wearables for stress tracking

As we mentioned, there are a whole host of devices that promise these stress tracking features, be it for general mental wellbeing or something more centred around fitness and keeping you in tip top shape. These devices mainly live on the wrist, but there's the odd one that takes those features elsewhere on the body to bring those stress monitoring to the fore.


Garmin stress tracking wearables

Most of Garmin's latest wearables now offer stress tracking, and it's standard up and down the range.

It's a feature that is powered by Firstbeat, taking heart rate variability measurements throughout the day and night and is able to break down stress into low, medium or high stress.

It also factors in rest too. It then provides a daily score from 1 to 100. A lower score indicates lower stress levels and that you've had enough restful moments in the day to balance out the stressful ones.

garmin stress tracking

As well as seeing daily scores, you can view trends over a week, month and year to see stress scores over a longer period. So you might find a particular month might be more stressful than others.

The feature also puts a big focus on sleep and by wearing your stress tracking wearable at night, can help reveal how well sleep has aided recovery from stress experienced in the day.

The other aspect of stress tracking on Garmin wearables, particularly its pricier devices revolves around physical stress. How this can relate to recovery between exercise and general state of fitness. Measuring your HRV when you’re active helps you to see when you’re in training zones.

This is done by performing an HRV stress test. This test requires an external heart rate monitor chest strap, which is used to measure heart rate variability while standing still for three minutes.

garmin stress measurement

Like all-day stress tracking, Garmin serves up your stress level on a range from 0 to 100. 0 to 25 is a resting state, 26 to 50 is described as low stress, 51 to 75 is medium stress and 76 to 100 is high stress. Although there aren’t insights about what you can do with that score, it does help to be able to see at a quick glance how your body is reacting in real time.

This stress tracking feeds into its Body Battery feature, which uses HRV along with sleep quality and activity tracking to help you keep a closer eye on your energy levels. It's also used to provide data for Performance Condition and Lactate Threshold insights more related to training.

In Garmin's newer watches like the Forerunner 745 and the cheaper Forerunner 55, it now uses those stress measurements to feed into assessing your recovery time and when you should plan to tackle your next hard workout. It uses that insight along with sleep and daily activity data to better suggest when you should consider taking it easy.

Garmin also includes guided breathing exercises, which takes into account HRV and respiration data. It can prompt whether to make use of these exercises to help get you to a calmer state. Paik tells us that the types of breathing exercises it's chosen to include are ones that have proved popular with regular practitioners and offer enough variety in terms of timing and purpose.

Samsung smartwatches

Samsung smartwatches

Samsung also uses the heart rate monitor built into its watches to unlock stress tracking just like many of its rivals.

It uses heart rate variability measurements to generate the stress tracking insights, which can be checked via the dedicated watch face. In that same app, you can see weekly graphs plotting out stress scores.

It's here where you can also access Samsung's breathing exercises, which uses deep and slow breathing to help reduce stress. Then you'll need to follow the on-screen animations on when to inhale and exhale during the exercises.

For the Galaxy Watch Active, Galaxy Watch Active 2 and Galaxy Watch 3, Samsung has also teamed up with up with mindfulness and meditation app Calm to take combatting stress further. The integration lets you pause and play Calm’s meditation sessions from your wrist.

What’s even more useful is that, after meditating, you can see a breakdown of your stress levels on the watch. To start a session, head to the Samsung Health app and go to the Discover tab. Once you've started a session, a notification will appear on your watch telling you that your stress will be monitored during the session.

Samsung Health has had some Calm integrations in the past, but this latest collaboration could help to remove the friction to meditate – rather than having to get out your phone, it’s now on your wrist. It’s a small difference but could be key for people hoping to turn meditation into a daily habit.

Apple Watch Series 7 and Watch SE

Stress wearables: best devices that monitor stress and how they work

The Apple Watch Series 7 and the Watch SE don't have a stress monitor feature built in, although there are third party Apple Watch apps that will do the trick.

However, there's a Mindfulness app which is designed to tackle stressful feelings, which was overhauled in watchOS 8 in 2021.

All of Apple's smartwatches (apart from Series 0) include a heart rate monitor and have the ability to take HRV measurements to fuel features centred around stress. This can be found in Apple Health.

Read this: How to use Apple Watch Breathe app

When Apple launched watchOS 3, it introduced its Breathe app with the goal of helping you to relax by focusing on your breathing. HRV measurements underpin how that feature works. The app offers daily reminders every five hours to take time out to work out on your breathing is tied to an age old meditation technique.

The Breathe features can now be find in the Mindfulness app in watchOS 8 – but does the same thing.

Using the Watch's taptic engine, you can pick from one or five minute sessions. A series of small vibrating buzzes will replicate a more calming breathing rhythm as you follow the instructions and animations on the Watch display to indicate when to inhale and exhale. It also monitors heart rate to add to your breathing session data when the Watch pings to indicate the end of a session.

You will also find new Reflect prompts, displaying short messages that are designed to promote positive thoughts.

Apple also takes heart rate variability measurements when using its Workout app for exercise, which can be tricky to locate inside of its Health app, but it is present for you to dig into post workouts to help identify trends related to stress on your body.

There are also third party apps, like EliteHRV that takes that heart rate data to help track recovery and stress levels related to exercise.


Stress wearables: best devices that monitor stress and how they work

Fitbit is making a bigger noise about how it wants to help you monitor stress and also how to help address it. Particularly with newer devices like the Fitbit Luxe and its Versa and Sense smartwatches. You can read our full explainer of Fitbit stress tracking.

Like Apple, it does similarly offer guided breathing exercises you can follow on devices with built-in heart rate monitors to help you de-stress. That includes the likes of the Fitbit Versa 3 smartwatch and its Charge 4 fitness tracker.

These are simple guided breathing visualisations that are personalised to you and heart rate variability measurements to determine a comfortable breathing rate. These features are based on research that shows that taking a few minutes in your day to relax can help to reduce blood pressure and lower your your risk of cardiovascular disease.

When set up and accessed from its Relax app, you'll have the choice of two minute or five minute sessions with both offering guidance when to inhale and exhale. The idea is to sync your breathing up with the circle, which provides haptic feedback when you get it right. If you spot the sparkles, that indicates that your breathing is in sync with the exercises.

On top of those guided breathing features it's also offering more stress-centric features in its companion smartphone app. You can track stress through Reflections, which involve logging your mood on a scale. There's also stress scores, which are generated from a collection of metrics including heart rate, activity and sleep patterns to offer a score much like its sleep score.

You'll also find a host of mindfulness features, which has to be fully unlocked through a Fitbit Premium subscription. These include listening to its full range of meditation sessions that are available through the app.

Google Wear OS smartwatches

Google Wear OS smartwatches

Google has been making big improvements to its Google Fit health and fitness platform and will be making some sizeable ones with the Wear OS 3.0 software update it's working with Samsung to launch this year.

Until that lands, the current version of Wear across its many watches offer the ability to access new guided breathing features that are very similar to what Apple, Samsung and Fitbit offer from the wrist.

Available on all Wear OS smartwatches with heart rate monitors, it can be found inside the Google Fit app. Breathing exercises take two minutes and you'll need remain still to complete the exercises.

The screen will prompt you when to inhale and exhale with an animated ring, helping to slow down your breathing to a more relaxed pace. When you're done, you'll get a summary of your breathing time and how many deep breaths you managed during that time.

Google has recently added a dedicated Tile (widget) to keep closer tabs on your stressful moments and you can also hunt out third party apps in the Google Play store to enhance the way you can monitor those stressful moments in your life.

While Google isn't necessarily bringing anything groundbreaking in this space just yet, it might just have bigger plans when it's big new software update finally lands.

Muse 2

Muse 2

Now for something slightly different. Muse is a wearable that's all about sensing what's going on in your brain and allowing you to change your state yourself, rather than zapping you with electric signals.

Using seven EEG (Electroencephalogram) sensors along your scalp, the Muse measures your brain activity in real-time and alerts you to calm and stressed moments through audio cues. It then guides you through a series of exercises in order to train yourself and identify distractions.

The idea is you'll then be able to go it alone and apply these calming techniques to your daily routine. So it's essentially just meditation for those who need a tool to help them out.

With the Muse 2, the company added a pulse oximeter to track heart rate rhythms along with the ability to monitor body movements and breathing to make it a more useful meditation device and tailor sessions driven by mind activity, breathing and heart rate. There's now also the Muse S, which adds sleep tracking into the mix if you want a dedicated device for that too.