What's the point of HRV biofeedback?
Heart rate variability (HRV) or the study of heart rhythms, is just one apparently simple measure of physiological state and yet it gives us a powerful indicator of our inner emotional states and level of stress. With any of the NeXus systems and a BVP or EXG sensor you can explore HRV and tackle its many applications including stress related mental and physical health issues and sport peak performance.
It has been known for many years that negative emotions and high stress lead to increasing disorder in the heart’s rhythms whereas positive emotions lead to what we can refer to as increased coherence.
Scientific research now tells us plainly that anger, anxiety and worry significantly increase the risk of heart disease, including sudden cardiac death. A 20-year study conducted by Eysenck and colleagues at the University of London concluded long ago that unmanaged reactions to stress were a more dangerous risk factor for cancer and heart disease than either cigarette smoking or high cholesterol foods.
HRV measurement gives us a window into the status of the autonomic nervous system (ANS) and as we will see some leverage to deal with stress. We can use biofeedback approaches to encourage an individual to naturally learn greater control over their state of ANS balance using the HRV as the feedback signal.
The ANS is commonly described in terms of the so called Sympathetic and Parasympathetic branches. Although this is a simplification, it nevertheless gives us a starting point to explain how our physiology responds to the pressures imposed by life.
When you really think about it, for centuries the heart has been considered the seat of our emotions - the source of our courage and passion. Yet at the same time ancient physicians saw the heart basically a simple pump - no sign of the soul or anything else in there.
It has only recently been realised that the heart is far more than a simple pump; in fact the heart possesses it’s own “little brain” that influences and is influenced by the status of our nervous system. This fact has massive implications for our understanding of the impact of the nervous system on the heart’s function and vice versa
In the 1960’s and 70’s John and Beatrice Lacey pointed out that the prevailing view of how the ANS worked was not completely matching their experimental observations. It was clear that we had a body wired for “fight or flight” - the Sympathetic branch of the ANS energises “us” for fight or flight and the Parasympathetic branch acted like the brakes to damp down the state of arousal once the threat has gone.
When we are at rest we are in a state of ANS balance. Human evolution in effect provided us with a physiology designed for survival, but in an era when life was much simpler than today. If the real world threat we face is something we can fight or run away from, then the ANS works well. Unfortunately, in todays world the threats we face can be as subtle as a piece of paper (the bill we cannot pay) or stationary traffic on the motorway; neither of these events can be dealt with easily via fight or flight. The result can be we get “stuck” in a state of arousal and the result is damaging stress due to the impact this has on our major body organs including the heart. The effect is both short terms and long term with the release of hormones that lead to premature ageing. Stress impacts upon our cognition - our ability to concentrate and remember so performance on both a physical and a mental level is compromised.
To return to the Lacey’s story, they noticed that in some situations the heart appeared to be sending messages to the brain that it not only understood but obeyed. In effect these messages could change a person’s behaviour.
Neurophysiologists have since discovered a neural pathway and mechanism whereby input from the heart to the brain could “inhibit” or “facilitate” the brain’s electrical activity. In fact the vagus nerve carries many of the signals from the heart to the brain. Research in neuroscience is confirming that emotion and cognition can best be thought of as separate but interacting functions or systems, each with its own unique type of intelligence.
The leverage we have to deal with stress exists “naturally” within each of us. Once we understand that even changing our breath pattern can rebalance our ANS we are on the brink of finding greater control. Manhandling our emotions to conjure up more positive “stress busting” ones can seem challenging but part of the battle is won through changing our awareness of our state and this is where biofeedback comes in. By employing biofeedback techniques you have available a non-invasive tool to get your ANS back on track. This is as helpful to the athlete seeking to manage the stress of peak performance as it is to the man in the street dealing with anxiety and depression.
Lacey, J. I. and B. C. Lacey (1978). “Two-way communicationbetwe en the heart and the brain: Significance of time within thec ardiac cycle.”
American Psychologist (February): 99-113.
Grossarth-Maticek, R., H. J. Eysenck, et al. (1988). "Personality t ype, smoking habit and their interaction as predictors of cancerand coronary heart disease."
Personality and Individual Differences9(2): 479-495.