07 Dec How is stress measured?

The physiological response of mental and physical stress can be measured at the heart. The StressCoach App measures the heartbeat for this purpose. To understand the relationship between heart rate and stress, you need to know more about the control of the heart rate by the autonomic nervous system.

Autonomous nervous system
The autonomic nervous system takes care of all unconscious processes. These include breathing frequency, blood pressure and heart rate. The autonomic nervous system consists of the parasympathetic and the sympathetic neural system. These neural systems both start in the brainstem and have an important function in regulating the functioning of many organs in the body, including the heart (Porges, 1992). The parasympathetic system is responsible for processes related to rest, growth and recovery, and the sympathetic system for physical activity and mental stress. Normally the parasympathetic system has the upper hand and you are in relative peace. As soon as you take action, the influence of the parasympathetic system decreases, the influence of the sympathetic system increases (Porges, 1992). The situation in which sympathetic activity prevails for a long time (chronic stress) is associated with various pathological conditions, negative emotions and depression (Thayer & Sternberg, 2006). It is, of course, important to prevent this.

“HRV describes the variation in time between successive heartbeats”

Vagus nerve
The vagus nerve, the tenth cranial nerve, is the large nerve of the parasympathetic system. You can monitor stress by examining the activity of the vagus nerve. The organ that is easiest to measure non-invasively and under control of the parasympathetic system is the heart. This is why measuring the activity of the heart is a great way to centrally monitor autonomous processes in the body, parasympathetic activity and therefore stress levels (Porges, 1992).

HRV
However, the measurement goes beyond the heart rate, which we measure in beats per minute as an average. If you measure the time of each individual heartbeat, you can measure information about stress. The measure used for this is heart rate variability (HRV). HRV describes the variation in time between successive heartbeats (Niskanen et al., 2004; Porges, 1992). The parasympathetic system increases the variation. When the sympathetic system prevails, heart rate variability decreases (Hamilton & Alloy, 2016; Thayer & Sternberg, 2006). By measuring your stress level every morning after waking up with the StressCoach App you gain insight into the degree of chronic stress.

Are you curious and do you want to measure your stress? Sign up for free via StressCoach App.

Literature
Hamilton, J. L., & Alloy, L. B. (2016). Atypical Reactivity of Heart Rate Variability to Stress and Depression: Systematic Review of the Literature and Directions for Future Research. Clinical Psychology Review, 50, 67–79.
Niskanen, J. P., Tarvainen, M. P., Ranta-Aho, P. O., & Karjalainen, P. A. (2004). Software for advanced HRV analysis. Computer Methods and Programs in Biomedicine, 76(1), 73–81.
Porges, S. W. (1992). Vagal Tone : A Physiologic Marker of Stress Vulnerability. Pediatrics, 90, 498–504.
Thayer, J. F., & Sternberg, E. (2006). Beyond heart rate variability: Vagal regulation of allostatic systems. Annals of the New York Academy of Sciences, 1088, 361–372.