Today a growing number of wearable devices promise insight into stress, wellbeing and your body's ability to recover from hard workouts.
At the center of this movement is Firstbeat, a physiological analytics firm based in Finland. A host of wearable brands use Firstbeat's analytics engine to decode the data from heart rate monitors, to unlock data related to stress, recovery, VO2 Max fitness levels and more.
Firstbeat's stress tracking debuted last year across Garmin's Fenix, Forerunner and Vivo devices, and more recently, aboard the Suunto 3 Fitness. It's designed to offer insights into what your body is doing on a daily and nightly basis, and untangle the mysteries of stress on your body.
Introducing heart rate variability (HRV)
The secret ingredient, the physiological phenomenon that makes these types of insights available, reliable, and scientifically valid is heart rate variability (HRV).
Your heart rate is constantly changing from one beat to the next, responding to the challenges of life and environment. HRV is the tiny changes, measured in milliseconds, which contain a wealth of information about what's happening inside your body.
Firstbeat can decode and interpret these patterns to reveal activation of the sympathetic (fight-or-flight) and parasympathetic (rest-and-digest) systems. This ability provides the scientific foundation for today's stress tracking tools.
Taking the Firstbeat Lifestyle Assessment
Long before smartwatches and fitness trackers became sophisticated enough to analyse HRV, Firstbeat was developing the necessary analytic tools and applying them in the Firstbeat Lifestyle Assessment. A staple of health and wellness programs, the Lifestyle Assessment has been performed over 250,000 times in northern Europe and in the UK.
The Firstbeat Lifestyle Assessment measures HRV for 72 hours using a high-resolution ECG recorder capable of pinpointing each heartbeat to the millisecond, looking for three key metrics.
The first is physiological stress reactions, which relate to an elevated activation level in the body – in other words, not how stressed you feel, but how stressed you are physically.
The second part of the test looks at how your body replenishes its resources, by monitoring your heart while you're asleep and during peaceful moments during the day.
Third is physical activity, which simply looks at how active you are during the day and how your body copes.
We took the test – which involved wearing the company's heart rate monitor for 72 hours. Why 72 hours? According to Tiina Hoffman, a professional exercise physiologist and wellness specialist at Firstbeat, this amount of time provides enough information to paint a clear picture of how you spend your days and nights.
At the end of the 72-hour recording period we sent the system back to Firstbeat, where its health professionals crunch the numbers. What we receive a few days later by email is a 7-page PDF document that in isolation looks like a lot of graphs, numbers, and colors. That's why Firstbeat provides one of its experts to talk you through the data, explaining what it all means, and helping you pinpoint areas for you to work on.
Our assessment results
In the assessment summary, our overall lifestyle assessment score is a 'good' 82 out of 100, which is a score based on the combined stress and recovery, sleep and physical activity results over the recording period. The average score of all lifestyle assessment participants is 55, so our data is pretty good compared to average, which is good news.
But there are some things to address. On my first day (screenshot above), the graph of the day shows a lot of red and green. Normally seeing red is a reason to be alarmed but in this case, this is to illustrate the stress reaction data. While there are a few spikes in the morning prior to work and around 10pm where we would have been returning home after grabbing a 47-minute swim after work, it's pretty consistent. The swim where we weren't able to wear the device explains the lack of blue in the graph to indicate our physical activity.
What is more interesting here though is our sleep data. We don't get enough sleep and while on two days of the assessment (which includes a Saturday) where we maxed out on sleep scores, the first day of the assessment sees us clock less than six hours.
The Firstbeat system measures heart rate variability to record the amount of recovery during sleep as well as the quality of recovery during that period. While we record less than the recommended eight hours of sleep, the restorative quality of sleep was actually good. This is indicated by a stream of green during this period. It if was bad quality, there'd be a whole lot of red in there instead. This may relate the exercise earlier in the evening, but had we slept for longer, we'd have been better off. It's something to bear in mind.
Stress measurement via the wrist
As well as completing the Firstbeat Lifestyle Assessment experience, we were also wearing the Firstbeat-powered Garmin Forerunner 935 to see how it compared. How can an optical wrist monitor compare to a full 72-hour test with specialist equipment?
Garmin's own proprietary Elevate optical heart rate monitor feeds uses Firstbeat's algorithms to measure HRV throughout the day and night, to record stress on the body.
You can perform a quick stress level on the watch. Once you've installed the stress test widget to the watch through Garmin Connect, you'll be able to scroll to the dedicated screen on your watch. You'll need to remain still to take a reading and if that score is high, you'll be prompted to take a moment to relax using Garmin's relax timer feature.
All-day stress tracking on the same day with Garmin Forerunner 935
This also feeds into an all-day stress tracking support, which happens in the background as long as continuous heart rate monitoring is activated on the watch. To view that all day stress tracking data, you'll need to head to the Garmin Connect app and look for the Health Stats section.
Here you can see stress data over a day, week, month and longer with a score allocated just like you get with the assessment tool. The scores work as following; o to 25 is a state of rest, 26 to 50 is low stress level and 51 to 75 is medium stress and 76 to 100 is high stress.
Comparing the same day's data from the Garmin Forerunner 935 and the Firstbeat Lifestyle Assessment, you can see similar spikes for stress and resting periods. A score of 20 on the Forerunner 935 indicates that I had enough relaxing moments on this day to balance out any of the stressful reactions.
While the assessment offers much more insight and detail, it was pleasing that results were consistent between the wearable-based Firstbeat results on the Garmin Forerunner 935 and the Firstbeat Lifestyle Assessment. It shows how much can be done with an always-on optical sensor, when using the right software.
The importance of HRV
What it all goes to show is how much valuable data heart rate variability can unlock about our bodies and lives. It goes way beyond the usual heart rate data metrics of knowing how hard you're working out or knowing when you're your heart rate is abnormally elevated. HRV brings another layer of biometric data capable of revealing more about our health and wellbeing.
Yes, it can give athletes a better sense of how to optimize training and help their bodies adequately recover in between sessions, but it's also goes further than that by offering greater insights into the need to balance all aspects of your life.
It's also about recognising how HRV-based insights can help you make smaller changes that can in turn create bigger more impactful changes that in the long run will hopefully help you live healthier and fitter for longer.
Firstbeat is championing this with its technology and continues to do so by appearing in more wearables that have the heart rate monitoring powers to unlock its impressive analytic tools. This is the next level of wellness tracking.