Stress has negative effects on the health of the body and the health of economies. When a person is feeling stress, the body releases certain chemicals that lower the immune system, increasing the likelihood that illnesses will form in the body. Stress can also cause negative effects in the workplace, as when workers take time off and seek treatment, the companies they work for lose money as well. The Mental Health Foundation estimates that around 12 million adults living in the United Kingdom visit their General Practitioner every year with concerns of their mental health that have been brought on by stress. Due to these illnesses, an estimated 13.3 million work days are lost every year. The World Health Organization estimates that around 8.4 million GBP (10.5 million USD) are lost by UK businesses due to these health concerns. Moreover, the average wait time to get treatment is 3-6 months. Because of these factors, over the last decade studies performed on stress and mental health have increased in popularity.
Researchers, Mozos, Oscar Martinez, et al. aimed to detect stressful behaviors by having their participants wear noninvasive physiological monitoring systems to find what activities elicited stress. These experiments were performed in a laboratory setting, using the TSST (Tier Social Stress Test) to manage levels of anxiety in each participant in a controlled situation; this popular method was used in over 4,000 settings over the last decade. The total sample size the researchers used was 18, male and female volunteers from the School of Psychology at the University of Lincoln in the UK.
The social task presented was for the subject to prepare a presentation for a mock job interview, and tasked to speak continuously for five minutes. When subjects paused the first time, the experimenter would tell them their remaining time and ask them to continue. The second time the participant paused they would be asked a set of predefined interview questions. For the cognition task, the experimenter asked the participant to count down from 1022 in sets of 13, for five minutes. If the participant made a mistake, they were asked to start from 1022 again.
Using the wearable, dual-signal BioNomadix, researchers wirelessly recorded electrodermal activity (EDA) and pulse plethysmograms (PPG), then analyzed the data to gather the Heart Rate Variability (HRV) between different tasks the subjects were doing, and extrapolate the stress the subjects were feeling in those conditions. The goal of the researchers was to show that using wearable monitoring systems can help detect stress, and with variations, can be applied outside of the lab, and into everyday interactions to get a firmer grip on what is causing anxiety and stress in millions of people.
