INTRODUCTION

In the last 30 years the HRV (Heart Rate Variability - the beat-to-beat alterations in heart rate) - have received an increasing attention as a forecast indicator of risk related to a number of chronic diseases, morbidity rates, mortality, and aging. Now the majority of the medical fraternity considers HRV as one of the most reliable indicators of Nonspecific Adaptation Deficit (NAD).

The NAD concept was created and developed by a medical team under the supervision of Prof. Dr. Svetoslav Danev, Doctor of Medical Science. According to this concept, the life-threatening diseases are preceded by certain nonspecific changes. These changes include depletion of the capacity for adaptation to unfavorable changes in the external or internal environment of the organism separate in function but mutually dependent. The increased requirements, which the organism faces, and the decreased capacity for adaptation create a vicious circle from which the only exit is lethal diseases and death. In terms of physiology it is based on decreased work efficiency of the negative back connectors, which plays a major role in the regulatory activities of the centers for coordination and regulation of the basic life processes. The descriptive frame presented very well fits within the general adaptation syndrome of Celier.

Long-term researches and monitoring of large contingents of practically healthy workers and employees revealed several important characteristics of the production processes characterized by unfavorable job conditions and work shifts – higher numerical values of permanent and temporary disablement, high employee turnover and nervous-emotional tension, and generally lower working capacity. The psycho-physiological research and examinations demonstrated that the normal homeostatic balance of the organism is replaced by a new heterostatic balance. This, in turn, reveals overstress and depletion of adaptation reserves. What is typical of this heterostatic balance is that the psycho-physiological “cost” of the adequate adaptation to the work environment is increased. This results in objective changes in a large class of functions and bio-constants. We discovered that in terms of the vegetative system, this condition is reflected by a chronic increase of activity of the sympathetic part of the vegetative nervous system in a new direction toward unjustified “ergotropic” adjustment of the system (even in periods of complete rest). This leads to the conclusion that the chronically increased ergotropic status in rest is a biological indicator of the NAD.

Panin and Bajevski first have proved that Heart Rate Variability (HRV) reflects the stress provoked by cosmic flights. Later, Prof. Dr. Svetoslav Danev, in a series of well-controlled laboratory experiments, discovered a strong positive relation between the changes in HRV and the necessary mental efforts.

Recently, HRV is used for assessment of the negative influence of a wide spectrum of stress types, including environmental pollution, dietary problems, psycho-social discomfort, and different behavioral disorders.

It was also proved that HRV reflects the degree of progress in many clinical diseases (for example, diabetes, hypertension, thyreotoxicosis, leukemia, different types of oncological diseases, etc.). That is why, in the last few decades HRV became one of the best diagnostic instruments in contemporary medicine. The practical application of the method, in ecological and professional aspects, requires software and hardware facilitation. One possible realization is our Danev Test which encompasses theoretical and clinical studies with a proven patient monitoring methodology.

Our procedural methodology for use in North America is for clinical studies and feedback purposes, pending necessary approvals.