Stress is a ubiquitous phenomenon in our lives, affecting not only our emotional well-being but also our physical health. In fact, when it becomes chronic, it can cause a variety of disorders, from anxiety and depression to cardiovascular disease and changes in the immune system.
And despite its relevance, accurate assessment of stress is an ongoing challenge in clinical and research settings.
Although observing people’s behavior has been the predominant method of measuring behavior for decades, progress in the development of biomarkers—a broad category of clinical signs, physiological changes, or objective signs of pathological conditions—has opened up new possibilities in recent years.
This evolution marks a new era in which we strive to integrate the subjective and objective to improve the identification and treatment of stress.
Self-report: a window into subjective experience
Traditionally, stress has been assessed through questionnaires and self-report scales, where people describe their own experiences and perceptions. Instruments such as the Perceived Stress Scale (PSS), the Stress Questionnaire (SRRS), and, for the work environment, the Job Stress Questionnaire (JSS) are widely used in clinical psychology.
The main disadvantage of self-report is precisely its subjective nature: it can lead to a discrepancy between what a person reports and his physiological reality. A person’s response can be influenced by cognitive biases, such as the tendency to minimize or exaggerate symptoms, and even their mood at the time.
In addition, cultural factors and individual differences in identifying and reporting stress may influence the results. All these circumstances limit the accuracy of the assessment.
However, despite its limitations, self-report remains a valuable tool because it provides information about the psychological dimension of stress. Ultimately, it is the subjective experience that causes some of the emotional and behavioral reactions associated with this state of tension. Ignoring this will result in partial or incomplete assessment.
Biomarkers: let’s ask your own body
Great technological advances in recent years have made the development of biomarkers possible. Unlike symptoms, which represent a patient’s perception of their health or illness, biomarkers can be measured accurately and reproducibly. Moreover, they can be detected regardless of a person’s experience.
Chronic stress is a pathological condition that alters the systems that maintain the balance of our body (homeostasis). Consequently, this gives rise to chemical or physiological signals that act as biomarkers.
Cortisol has probably been most widely used in research and clinical practice. The problem is that levels of this hormone vary widely due to contextual or individual factors. It may also fluctuate depending on the time of day at which it is measured.
Currently, new, more objective and effective biomarkers are coming onto the scene. An example is heart rate variability (HRV), the change in time between each heartbeat, measured in milliseconds and reflecting the balance of the autonomic nervous system.
When we suffer from chronic stress, the function of the autonomic nervous system changes, causing not only the typical symptoms of stress, but also a decrease in HRV. This reduction works as a powerful biomarker of both stress and physical and mental health and well-being.
The electrical activity of neurons can also be recorded using quantitative electroencephalography. This method creates detailed maps of the brain that reveal specific patterns of activity. The important thing is that in situations of chronic stress, the maps revealed by this technique appear to be altered.
Constantly monitored
The use of these biomarkers allows early, objective and independent detection of clinical symptoms. This facilitates treatment or intervention in the initial stages, which prevents assessment by answering validated questionnaires after the stressful events have already passed.
On the other hand, the development of wearable devices that can measure both HRV (watches or apps) and brain activity (electroencephalographic patches) has made a significant contribution to improving the timely detection of stress. These devices wearable devices (wearable) provide continuous monitoring without requiring people to visit a laboratory with specialized clinical equipment.
Continuous monitoring combined with early intervention will improve the population’s quality of life and reduce the costs associated with stress-related illnesses. A notable example is the Finnish Institute of Occupational Health’s program, which promotes HRV measurement to reduce stress in the workplace.
A revolution with promising consequences
In short, the combined use of self-reports and biomarkers allows us to overcome the limitations inherent in each method when used alone.
We can firmly argue that new portable technologies for recording cardiac and brain activity, and the ability to continuously monitor these signals, represent a revolution in the assessment of stress, with promising implications for public health and personal well-being.