Taking the (Often Imprecise) Measure of Stress
Research has long shown that stress is bad for you, but many people are not even aware when they are feeling stressed.
Now, a number of new devices are sold as stress trackers, measuring signs of stress the way fitness tracking devices monitor steps and movement. The gadgets track the biological symptoms of stress — changes in skin perspiration, breathing patterns and heart rate — in hopes of helping people become aware of their stress levels.
One of them is Spire, a stonelike device that clips to a belt or bra and senses the expansion and contraction of the chest cavity during breathing. The device, which retails for $149.95, sends phone notifications when it detects a change in breathing patterns that may indicate stress. “Your breathing suggests you’re stressed,” it says. “Take a deep breath.”
The Pip stress manager ($179 retail) uses electrical changes at the surface of the skin to measure an individual’s stress response. The user holds the teardrop-shaped device between the thumb and forefinger and the device collects data and analyzes it with charts and graphs that monitor stress on a given day or across weeks or months to find patterns, such as what time of day is most stressful for you.
The downside of most devices is that while breathing patterns and skin sweat certainly can signal stress, they can also indicate a range of emotions and activities. Physiologically, there is not much difference between the stress of a work deadline and the excitement of watching your favorite sports team. Even going for a brisk walk stimulates a similar response from the sympathetic nervous system, which runs the body’s fight or flight mechanism. The same thing occurs in certain stages of sleep.
Most apps and devices that claim to track or reduce stress lack scientific rigor, said Dr. Rosalind Picard, a professor at the Massachusetts Institute of Technology’s Media Lab, who straps stress monitors onto the wrists of visitors to her Cambridge office.
大多数自称可以追踪或减少压力的应用程序和设备都缺乏科学严谨性，麻省理工学院(Massachusetts Institute of Technology)媒体实验室(Media Lab)的教授罗莎琳德·皮卡德(Rosalind Picard)博士说道。她喜欢给造访她在坎布里奇(Cambridge，麻省理工学院所在地)的办公室的访客们在手腕上绑上压力监测器。
It is hard to objectively determine someone’s stress in the real world — accounting for individual variation, diets, lifestyles, medication and other environmental factors, Dr. Picard said, adding, “If you want to learn about human variability, measure stress.”
But that has not stopped Dr. Picard from trying. She is chief scientist at Empatica, which will soon release its $199 Embrace watch. It takes stress monitoring a step further than most by tracking skin temperature, movement, sleep, respiration, heart rate, heart rate variability and skin conductance, a measure of electrical charge that reflects changes in arousal. The watch vibrates when it detects a rising stress level. (The device is also designed to alert people with epilepsy of an impending seizure.)
Neumitra, a start-up based in Boston, is scheduled to release a watchlike stress tracker early next year, but has not released pricing details. The device, said the company’s chief executive, Robert Goldberg, will turn people into “citizen scientists,” feeding the tracker’s algorithm to make it smarter about what’s causing their arousal.
If someone consistently shows signs of stress when heading to a particular client’s office or when driving on the highway, the tracker may link them to their favorite tunes or lead them through breathing exercises to help reduce their stress.
Dr. Picard said she has worked with teachers who changed their approach when stress monitors showed their students’ anxiety triggers. One father had a long conversation with his son when a monitor repeatedly showed the boy felt more anxious around him. And Dr. Picard said she changed her own response to Boston traffic after an earlier version of her tracking device showed her how much she was letting other drivers get to her.
“I am a much more relaxed driver now,” she said.
Researchers at Microsoft in Redmond, Wash., are testing how to deliver useful stress reduction tips. In one monthlong study, participants were instructed to do positive activities on their phone, like going to their Facebook timeline and looking for three people, objects or events they are thankful for.
“Maybe what you need to do is teach people a little bit and get out of their way,” said Dr. Mary Czerwinski, who is leading that study and is a research manager at Microsoft. “And maybe after a couple of months, if their stress levels are going up, maybe pop back in and remind them of what it was.”
But sometimes telling a person that he or she is stressed may end up just causing more stress. Dr. Czerwinski once worked with a study volunteer who got upset when tracking devices indicated that he was stressed. “No machine can know when I’m stressed better than I know I’m stressed,” the volunteer said angrily.
Some device makers are working to incorporate stress reduction into the device itself. Thync Inc. of Boston and Los Gatos, Calif., makes a headset that retails for $199 and uses nerve stimulation that claims to “recharge your mood,” provide calm, focus and energy, and promote sleep. The device creates an electrical circuit between the right temple and the back of the neck, modulating nerves on the head, face and neck, which are involved in sensory processing and mood. One level of stimulation is designed to reduce stress; a different level can reportedly stir feelings of bliss.
The only studies showing Thync’s success have come from the company itself, which has tested the device in about 4,000 people, said Dr. Jamie Tyler, a co-founder and the chief science officer.
Dr. Picard and Dr. Czerwinski said they remained skeptical that any currently available device could act on the body to reduce stress. Instead, Dr. Picard said she prefers a low-tech way of responding to her own anxiety: She gets up and goes for a short walk.
“It’s not only less expensive” than any device, she said, “but it’s probably better for my whole body, not just my brain.”