Although it is a condition common to all humans (and even animals), stress is harder to objectively describe than you might think. It is partly subjective, which is why questionnaires rarely work, and the tests used to determine stress levels are not only slow but also stress-inducing themselves. A convenient and noninvasive way to detect and measure stress levels could go a long way in preventing it or giving immediate treatment and that’s exactly what a new paper-thin sensor promises to deliver.
The basis of this new wireless sensor is the commonly accepted role that the compound called cortisol plays in our body. This is pretty much called the stress hormone and too much or too little of it could be a sign of stress, anxiety, depression, PTSD, and other similar disorders. As it turns out, cortisol can be detected in sweat, which is actually what this sensor is.
Using laser etching, a plastic sheet is engraved with a 3D graphene structure with tiny pores through which sweat can be analyzed. The amount of cortisol present in sweat is then transmitted wirelessly to a device, for example, a smartphone, in just minutes. In contrast, a cortisol blood test could take upwards of one hour to get analyzed and the results may be skewed due to the stress of getting blood drawn in the first place.
It isn’t yet an exact science as cortisol levels in isolation don’t directly mean the presence of stress. The data has to be compared with the wearer’s “base” circadian rhythm, which notes the normal rise and fall of cortisol levels during the day. Only when the results diverge from that standard can stress be inferred.
Such a wireless sweat sensor’s non-invasive and remote properties can be put to use in more than just patient monitoring here on Earth. NASA seems to be pretty interested in the work that Caltech medical engineering professor Wei Gao and his partners are doing in this area. The benefits of such a sensor for life in outer space cannot be understated, especially when direct testing and assistance is nearly impossible in this context.