Inside, it’s not hard to tell if you’re stressed. You may feel agitated, notice your tense shoulders or jaw, have headaches or even stay awake at night.
But outside it is a little more difficult to measure stress objectively and, in turn, to know how to treat it. But that could change soon.
Scientists have just published an article reporting the creation of a wearable electronic chip that can analyze how stressed you are by detecting a specific hormone in your sweat.
“Having a reliable and wearable system can help doctors objectively quantify whether a patient is suffering from depression or exhaustion, for example, and whether their treatment is effective,” said senior author and nanotechnology researcher at Ecole Polytechnique Fédérale de Lausanne Adrian Ionescu.
“What’s more, doctors would have this information in real time. That would be a big step in understanding these diseases.”
The chip tracks the hormone cortisol – a steroid hormone we’ve known for a long time – it is released by the adrenal glands in response to physiological stress, including physical stress or low blood glucose.
When your body releases cortisol, triggering those stressful feelings that we are all familiar with, it can be detected in saliva, sweat and pee.
“Cortisol can be secreted on impulse – you feel good and suddenly something happens that puts you under stress and your body starts producing more of the hormone,” says Ionescu.
The patch works using an extended gate field effect transistor (EG-FET) made of graphene to analyze small amounts of cortisol in our sweat. The transistor uses small fragments of DNA that bind to cortisol, dragging the hormone closer to the sensor.
This may sound like an exaggeration for the lucky enough to avoid persistent stress – after all, we all get stressed from time to time. But when stress levels remain high – also known as chronic stress – it can lead to a variety of problems.
“Disorders such as obesity, metabolic syndrome, type 2 diabetes, heart disease, allergy, anxiety, depression, fatigue syndrome and exhaustion are often associated with dysfunctions of stress axes,” wrote the team in their article.
The team expects the patch to be able to record cortisol levels over the course of an entire day, which will show whether the patient has a normal cortisol curve or if something is wrong.
“The cortisol level has a circadian rhythm in the serum throughout the day, with the highest level in the morning (~ 30 min after waking, 0.14–0.69 µM) and the lowest level at night (0.083–0 , 36 µM). Stress can interrupt this rhythm and result in an abnormal increase in the level of cortisol, “wrote the team.
“Although short-term activation of the hypothalamic-pituitary-adrenal axis is adaptive and necessary for everyday life, both high and low levels of cortisol, as well as disturbed circadian rhythms, are implicated in physical and psychological disorders.”
You can’t go out and get one of those stress patches yet, but the team hopes to test the sensor at a hospital soon. Watch this space.
The article was published in Communication Materials.