Like counting steps and tallying calories burned, tackling stress isn’t new territory for a smartwatch. Apple’s Watch can remind you to take a mindful moment and breathe during the day, and some of Samsung’s Galaxy Watches will try to guess your current stress level by looking at the characteristics of your heartbeat.
But more than most, Fitbit — which Google acquired in early 2021 to help flesh out its health and hardware initiatives — is trying to position high-end wearables like the $299 Sense 2 as tools to help us reflect on the stress we face everyday.
What might be most interesting about the Sense 2′s approach is the reactiveness of it all — it won’t prompt you to reflect on the nature your stress unless it thinks you’ve just experienced some. And to do that, it needs to take a pretty broad look at the ways your body acts in real-time, even if you’re not fully aware of them.
The key to spotting that stress in the moment, Fitbit says, is the “Body Response” sensor built into the Sense 2. In addition to looking at your heartbeat and tracking your skin temperature, the watch has a tool for continuously measuring your electrodermal activity — basically, a scientific measure of the shifting sweat levels in your skin.
Even if you’re not someone who experiences full-blown flop sweat when things go awry, those micro-shifts in sweat content of your skin can indicate different kinds of emotional arousal, including the onset of stress. And when the algorithm determines that the blend of sweatiness, heart rate, heart rate variability and body temperature look appropriately out of whack, the Sense 2 will flash a notification on its screen to check in with you — a few minutes later, anyway.
“A few hours later, you probably forgot what was going on,” said Elena Perez, group product manager at Fitbit. “In the moment, you may not be in the mind-set to really reflect if you’re going through a stressful situation.”
As part of that check-in, the Sense 2 asks its owner what they just felt — an important question considering that, physiologically, signals like a surging heart rate and heightened temperature can mean a lot of things. If you feel like sharing, you can tell the watch that you’re frustrated, worried, sad or excited and view some suggestions for managing those feelings in the moment. (Think guided breathing exercises or going for a short walk.)
Because the Sense 2 won’t go on sale until the fall, though, it’s not yet clear how well it can actually suss out our stress levels.
“It is definitely possible to infer stress using electrodermal activity and heart rate,” according to Rose Faghih, an associate professor of biomedical engineering at New York University’s Tandon school of engineering. Faghih’s research aims to measure mental activity through a similar set of sensors, though she couldn’t completely vouch for Fitbit’s approach.
“It really depends on the quality of the sensor,” she said.
And while certain people may benefit from a wearable that suggests ways to deal with difficult moments, some experts say those who feel routinely beset by stress should look beyond gadgets.
“It’s not equally accessible to everybody, but seeing a qualified therapist can, I think, do a better job of helping people design an individualized way to approach what they feel isn’t an optimal moment in their lives,” said Mark Seery, a stress researcher at the University at Buffalo. “Relying on a Fitbit to sort of be a proxy for something like that — I wouldn’t be super-excited to recommend that.”