Stress Assessment - Introduction


A large body of evidence leads us to the conclusion that chronic stress can affect mental and physical well being. The exact mechanism by which it imposes these detrimental effects is unknown. In the scientific and medical literature the list of physical diseases contributed to by stress is ever increasing. These include hypertension, coronary disease, sudden cardiac death from cardiac arrhythmia, gastric and duodenal ulceration, cancer due to immune suppression (Marshland et al 1995) and even Alzheimer's disease. These diseases arise not only from a direct effect of persistent stress itself but also from lifestyle habits such as smoking, excessive alcohol and overeating, which are at least in part attempts to find stability and coping mechanisms in our stressful environment.

Accepting that bad lifestyle habits contribute to disease, how does stress per se translate to a physical or mental detrimental effect at the cellular or homeostatic regulatory level?

The use of heart rate variability (HRV) is explained and how its measurement yields not only a measure of current stress but also more importantly the individual's stress reserves or stress vulnerability.

For over 40 years scientific research into how the action and interaction of the body's autonomic nervous system can be detected and analyzed in such a way as to give an insight into the body's total state of physical and mental health. As a result of this research program, an extensive patient study has been conducted, including a further study over the past 17 years of the behavioral patterns, and particularly the physiological responses to stress. This work generated a considerable database of individual patient studies, which has established the "normal" HRV level for any individual, taking gender and age into account. The final outcome of this research is a highly sophisticated clinical system that uses HRV to assess and predict certain disease states. One of the proven applications is to detect and accurately measure stress and perhaps more importantly, stress reserves or stress vulnerability.

The QMedical system has been developed purely to monitor the stress, stress reserves and autonomic balance of individuals. The system and equipment has been "tried and tested" by qualified clinicians operating over the past 10 years. This HRV monitoring equipment indexes the autonomic nervous system (ANS) and more specifically the sympathetic/parasympathetic nervous system balance. The balance between these two systems is an indicator of the body's reaction to external and internal demands.

Whereas homeostasis reflects the regulation of internal organs and the maintenance of internal balance by the parasympathetic nervous system (PNS), stress reflects subjugation of internal needs in response to external demand.

This new concept in understanding how the body reacts physiologically to stress highlights the need to measure PNS activity as an index of stress vulnerability. Historically, scientists have attempted to measure stress by measuring the activity of the sympathetic nervous system (SNS), which represents only one of the two important components of the autonomic response. However, by monitoring the activity of both components of the ANS it is possible to define not only current stress but also the stress reserve of the individual: the latter being a more useful measure, as it identifies an individual's susceptibility to the effect of stress.

The new concept forms the basis of our scientific monitoring capability. Furthermore, this document cites the scientific evidence that individuals who are chronically stressed have less heart rate variability, which is associated with reduced parasympathetic nervous system activity.

In addition to the physiological QMedical indicator, we score stress/anxiety and depression by way of selected questionnaires. We also quantify lifestyle stress by a brief lifestyle inventory, so that the healthcare professional can assess and counsel on any factors likely to be making significant contributions to a person's stress, e.g. smoking, alcohol, caffeine, diet and nutritional state (including nutritional supplements taken), exercise and sleep. The scientific evidence for the impact of these lifestyle factors on stress is also contained in this dossier.

Stress is an inescapable consequence of everyday living and everyday social interaction. At the clinic we aim to quantify stress levels and to identify individuals who are vulnerable to ill health due to compromise of stress reserves. The objective of QMedical is to promote better stress coping strategies for individuals, informing them how to gain control of their ANS and their body's stress response, and also building stress reserves through appropriate lifestyle changes.