Human Guinea Pig

I wore this $279 device over my heart to track stress — here's what I learned

Lief Therapeutics' new device helps you manage your stress

Wearable devices, including the Apple Watch, are now tracking one of the key indicators of stress: Heart rate variability, or more simply put, the variation between heartbeats.

It's not an exact science, but generally speaking, people who have a higher heart rate variability tend to be more resilient to stress, are often in a state of calm and may also be in good health. Those with a low HRV are often in fight-or-flight mode.

Most people will experience a wide variety of HRV figures throughout the day, depending on how stressed they are.

Personally, I've long questioned whether scientifically tracking stress is possible. For many of us, the "Big Brother" effect of having a device nudge us during moments of tension is stressful in and of itself. Plus, there are different types of stress, some good for us and some bad, which might not be evident in a continuous stream of data on an app.

So I decided to put one of these new stress trackers to the test.

I wore a new smart patch about the size of my fist from a company called Lief Therapeutics during times of both high and low stress. The device is designed to be worn right over the heart, and is accompanied by an iPhone app that includes a virtual coach to help users get through a series of calming breathing exercises.

The scenarios I selected to test my stress levels included a run around San Francisco's Ferry Building, a performance review with my editor and a deadline to publish some breaking deal news (this is about the most stressful thing imaginable in many a business reporters' day).

The pros

Anyone who responds well to changes in data will likely be motivated by the Lief device and app.

I've been told that certain types of breathing are positive, but actually visualizing it is a different story. That might be far more compelling for many people than listening to a therapist or doctor espouse the health benefits of taking a few minutes to relax each day.

I also appreciated that the app made it easy for me to tuck my phone away, so I didn't need to look at a screen while breathing. As an alternative to meditation apps, the Lief device vibrates to keep its users on the right track.

The Lief has huge potential to help its users better understand the emotions they're feeling, and their impact on health. The team says they are working with clinicians at UC San Francisco and Stanford to help its users record thoughts, emotions and behaviors to better understand how certain negative thinking patterns affect them. For now, I found it helpful to use the app to jot down notes throughout the day, so I could start to form a picture about the things that stressed me out the most.

The cons

The form-factor will need to improve to appeal to a mainstream market outside of early adopters. The device wasn't small enough at this stage to feel totally invisible under my clothes, and I did worry that it would lose some of its stickiness and slide off — particularly while I was working out.

Also, it didn't provide enough context around what the numbers meant. My run around the Ferry Building lowered my stress levels, but it took a while for the data to load. The performance review and deadline were definitely stressful, but I felt that clearly already, so having the data didn't really add anything.

I could see that the iPhone app's suggested breathing practice brought my heart rate variability higher, lowering my stress, but I needed to do some background reading to realize the value in that. There's also an orientation with a ton of information about mindfulness and understanding thought patterns, but that's an investment in time.

Should you buy it?

The device doesn't come cheap: $279 plus $20 for a pack of the stickers.

I wouldn't buy it at that current price. It wasn't clear enough how all the different activities really impacted my stress levels, although I did learn that deep breathing certainly made a difference. But that's also common sense.

At this point, I'd recommend it for anyone who needs to see the actual data to develop healthier habits. Otherwise, take my word for it. Take a breather once in a while.

Finally, and as a word of warning, don't be too surprised if certain relationships tend to push down that heart rate variability more so than others. And taking deep breaths around them might come off as passive aggressive.