We may be on the verge of devices that warn when you really, really need to take a holiday, producing a readout you can show your boss or doctor. The idea relies on continuous monitoring of hormones in sweat that reveal the level of stress being experienced. This, all going well, would serve as an early warning sign before burnout kicks in.
Cortisol is a hormone with a well-established connection to psychological and emotional stress. It serves numerous vital functions in the body, besides now being used to measure mental health. "Cortisol can be secreted on impulse - you feel fine and suddenly something happens that puts you under stress, and your body starts producing more of the hormone," said Professor Adrian Ionescu of Ecole Polytechnique Federale de Lausanne in a statement.
The fact that cortisol serves functions other than stress-response means it fluctuates for reasons unassociated with mental pressure, so the occasional test is not a very reliable indication of someone's state. To tell what is really going on, it is necessary to take cortisol readings throughout the day.
Cortisol is usually measured from blood samples – and having blood taken frequently could be a stressor in itself – but Ionescu noted the hormone can also be measured in more easily collected saliva, urine, and even sweat.
In Communications Materials, Ionescu and co-authors describe an electrochemical smart-patch to measure cortisol concentrations in the blood – an idea raised previously but at that point was some way off practically. The detector uses a platinum/graphene extended gate field effect transistor, but the quantity of platinum required is small enough that the famously expensive metal shouldn’t prevent mass production. Binding to cortisol causes small strands called aptamers to fold in such a way that they carry charge to the device's electrode, while other components of sweat do not, allowing detection at exceptionally low concentrations.
“Because it can be worn, scientists can collect quantitative, objective data on certain stress-related diseases. And they can do so in a non-invasive, precise and instantaneous manner over the full range of cortisol concentrations in human sweat," Ionescu said.
Not everyone can limit their stress, no matter how aware of the problem they are. For someone facing a life crisis, they can’t avoid it, and having a tracker telling them how stressed they are may just be a ticket to more stress.
Others, however, could use the sensor as a way to tell them when they need a holiday or some other form of circuit breaker. Moreover, Ionescu hopes the device could become a way to assess the effectiveness of treatments. “Having a reliable, wearable system can help doctors objectively quantify whether a patient is suffering from depression or burnout, for example, and whether their treatment is effective. What's more, doctors would have that information in real time.” he concluded.