Quelques infos supplémentaires, qui détaillent l'intéret des études de variabilités cardiaque (HRV) pour étudier cette relation cerveau/coeur via le système nerveux autonome
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ADDING THE INTELLIGENCE OF THE HEART IN PERFORMANCE ENHANCEMENT TRAINING
R. Adam Crane BCIA Senior Fellow, BCIAEEG, NRNP Diplomate
Science of The Heart: The Role of the Heart in Human Performance
Introduction
For centuries the heart has been considered the source of emotion, courage and wisdom. Neurocardiology is the relatively new science of exploring the physiological mechanisms by which the heart communicates with the brain; thereby influencing information processing, perceptions, emotions and health. Neurocardiology asks questions such as: Why do people experience the feeling or sensation of love and other positive emotional states in the area of the heart, and what are the physiological ramifications of these emotions? How do stress and different emotional states affect the autonomic nervous system, the hormonal and immune systems, the heart and brain? Over the years scientists have experimented with different psychological and physiological measures, but consistently heart rate variability, or heart rhythms, stands out as one of the most dynamic and reflective measures of inner emotional states and stress.
It is clear that negative emotions lead to increased disorder in the heart's rhythms and in the autonomic nervous system, thereby adversely affecting the rest of the body. In contrast, positive emotions create increased harmony and coherence in heart rhythms, and improve balance in the nervous system. The health implications are easy to understand. Disharmony in the nervous system leads to inefficiency and increased stress on the heart and other organs, while harmonious rhythms are more efficient and less stressful to the body's systems.
More intriguing are the dramatic positive changes that occur when techniques are applied that increase coherence in rhythmic patterns of heart rate variability. These include shifts in perception and the ability to reduce stress, and deal more effectively with difficult situations. Apparently, the heart is acting as though it has a mind of its own, and is profoundly influencing the way we perceive and respond to the world. In essence, the heart is affecting intelligence and awareness.
There is now a scientific basis to explain how and why the heart affects mental clarity, creativity, emotional balance and personal effectiveness. Research indicates that the heart is far more than a simple pump. The heart is, in fact, a highly complex, self-organized information processing center with its own functional "brain" that communicates with and influences the cranial brain via the nervous system, hormonal system and other pathways. These influences profoundly affect brain function and most of the body's major organs, and ultimately determine the quality of life.
Biofeedback researchers and practitioners are enthusiastic about the emergence of this new Biofeedback tool. Like Neurofeedback, Heart Rate Variability's (HRV) simple technical name belies its power and importance in the rapidly evolving field of life, performance enhancement and longevity. However, its effectiveness is amplified even more when combined with Neurofeedback training. Heart rate variability is a measure of the naturally occurring beat-to-beat changes in heart rate, a powerful, noninvasive measure of autonomic nervous system function and an indicator of neurocardiac fitness. The heart and brain maintain a continuous two-way dialogue, with each influencing the other's functioning. It is now known that the signals the heart sends the brain can influence perception, emotional processing, and higher cognitive functions. Let's start with a simplified discussion before we dig deeper into the hard science and technical jargon.
Throughout history philosophers have asserted that "when the heart enters the brain wisdom emerges". Now, neurocardiology has demonstrated that there are physiological correlation's for this ancient concept. Furthermore, these discoveries have been translated into a fascinating and enjoyable form of Biofeedback with enormous potential. Part of the reason for this potential is that people are attracted to the simple, common sense notion that there is something that can be done to assure that their thinking will be positively influenced by their hearts. Of course, heart represents one's humanity, compassion, wisdom etc., but most people are keenly aware that feelings in the heart profoundly affects health.
With HRV hard science is being applied in order to achieve the physical and psychological objectives of improved health and enhancement of intelligence. And skillful HRV training is doing so by increasing EQ (Emotional Intelligence - Daniel Goleman) and integrating all of that with attention and improved brain coherence. Using non technical language we can describe the process as follows: unhealthy stress causes thinking to become relatively incoherent and that correlates with incoherent brain wave activity. Incoherent (dysfunctional) brain wave activity leads to a decrease in general health and increases mistakes, lowering performance and enjoyment of life. This kind of dysfunctional thinking also influences the variability and coherence of EKG (heart rate) activity. The two dynamics then potentate each other leading to a downward spiral of quality of health and thinking.
One of the tenets of modern psychology and learning theory is that what we think determines our reality. "As you think so you are". Since the heart mediates the emotional system, and since thoughts with an "emotional charge" are those thoughts that most influence our life and our reality, it can be suggested that the heart truly is massively influencing the brain and our reality - if not dominating it.
Self regulation training of breathing and relaxation has always been one of the most important aspects of Biofeedback, reduction of maladaptive stress responses and performance enhancement. However, those who are expert at this kind of work have long complained that just mechanically teaching people how to relax the muscles and breath diaphramatically, and stop breathing dysfunctionally, is useful but not enough. Somehow, the teacher has to train the client to generate extremely subtle, so called "positive" feelings in the heart area (plexus). The problem is that such feelings are incredibly difficult to communicate verbally. Of course, they can be communicated non verbally, but it is a high art to do so. Skillful use of HRV Biofeedback training simplifies and accelerates the learning of these special feelings.
Think about the biological implications for consciousness. For example, the heart has many "brain cells" of its own, and secretes many "brain chemicals" including two of the most important in life and performance enhancement - serotonin (critical in managing stress) and oxytocin (critical in enhancing relationships or "bonding"). Furthermore it has been demonstrated that as the heart rhythms become more coherent so do the brain rhythms, and as brain rhythms become more coherent, so does thinking. Coherent thinking in turn leads to enhanced creativity or more theta brain waves which are associated with bursts of insight - the "eureka" experience.
Science of the Heart
The following offers a more technical description of neurocardiology and its implications for Biofeedback. The autonomic nervous system (ANS) profoundly influences the major organs. Sympathetic fibers pass through the cranium and sacrum; parasympathetic fibers are associated with thoracic and lumbar vertebrae. A number of health problems can arise in part due to improper function or balance in the ANS. The activity in the ANS and the balance between the two branches is greatly affected by emotions. For example, anger causes increased sympathetic activity and reduced parasympathetic activity. Constriction of the arteries resulting from excessive sympathetic stimulation can contribute to hypertension and heart attacks.
Biomedical research has revealed that the heart is not just a simple pump, but a highly complex, self-organized information processing center with its own functional "brain." With each beat, the heart continuously communicates with the brain and body via the nervous system, hormonal system, bioelectromagnetic interactions, and other pathways. Scientists are demonstrating that the messages the heart sends the brain not only affect physiological regulation, but can also profoundly influence perception, emotions, behaviors, performance and health.
The heart produces by far the most powerful rhythmic electromagnetic field in the body. The brain and all the cells in the body are continuously bathed in the heart's electromagnetic field, which can also be detected several feet away from the body by sensitive instruments. The implications are that the heart is an energetic system, and the heart's field is a carrier of emotional information and a mediator of bioelectromagnetic communication both within and outside the body. Many scientists believe that the heart's field changes distinctly as we experience different emotions, and is registered by the brains of people around us. The heart's field also appears to be capable of affecting cells, water and DNA studied in vitro. The implications of these findings are that people may be capable of affecting their environment in ways not previously understood; and that such "energetic" interactions may be prominently influenced by our emotions. Growing evidence also suggests that energetic interactions involving the heart may underlie intuition and important aspects of human consciousness.
The term physiological coherence is often used to describe a physiological mode that encompasses entrainment, resonance and synchronization, which are all distinct but related physiological phenomena that are frequently associated with more ordered and harmonious interactions among the body's systems. The coherence mode is associated with a sine wave-like pattern in the heart rhythms (reflecting increased synchronization between the two branches of the autonomic nervous system), a shift in autonomic balance toward increased parasympathetic activity, increased heart-brain synchronization, increased vascular resonance and entrainment between diverse physiological oscillatory systems.
In physics "coherence" is used in two different ways, both of which apply to the psychophysiological use of the term. It is used to describe the ordered or constructive distribution of power within a single waveform. The more stable the frequency and shape of the waveform, the higher the coherence. The term autocoherence is used to denote this kind of coherence. An example of a coherent wave is the sine wave. In physiological systems, this type of coherence describes the degree of order and stability in the rhythmic activity generated by a single oscillatory system. For example, in the physiological coherence mode, the heart rhythms become more coherent, shifting toward a sine wave-like pattern.
Coherence is also used to describe two or more waves (or systems) that are either phase - or frequency-locked. This is also called entrainment. In the coherent mode, respiration, heart rhythms, and blood pressure rhythms become entrained and oscillate at the same frequency. The term cross-coherence is used to specify this type of coherence.
In terms of physiological functioning, coherence confers a number of benefits to the system. For example, there is increased cardiac output in conjunction with increased efficiency in fluid exchange, filtration, and absorption between the capillaries and tissues; increased ability of the cardiovascular system to adapt to circulatory requirements; and increased temporal synchronization of cells throughout the body. This results in increased system-wide energy efficiency and metabolic energy savings.
An HRV training system has been reported to bring about increases in productivity, goal clarity, job satisfaction, communication effectiveness, improvements in employee health and well-being, and reductions in employee turnover. Achieving this kind of training and its extraordinary results can be accomplished with relatively low cost equipment and the appropriate software.
Source:
http://biofeedbackinternational.com/adam_hrv.htm
