Neurocardiology is a recently developed area of academic, scientific research initiated by the researcher J. Andrew Armour M.D., Ph.D. (1991) and is the study of how the nervous system and the cardiovascular system interact physiologically.

According to Demorree (2013), those suffering from psychological distress may be helped as more becomes understood about how the brain, nervous system, and heart all interact and affect each other.

THE HEART – BRAIN CONNECTION :

The heart and the brain are connected by nerve fibers, and, of great interest and with important implications (described in the rest of this article):

  • 90 % of these connections go from the heart to the brain

whereas…

  • a mere 10% go from the brain to the heart

(For those who are interested, the nerve fibers that ascend to the brain from the heart are known as AFFERENT PATHWAYS, whereas the nerve fibers that descend from the brain to the heart are known as EFFERENT PATHWAYS).

According to Armour, the heart may consist of up to 40,000 neurons (neurons are mainly found in the brain and are nerve cells that convey information via electrical and chemical signals; the brain itself consists of approximately 100 billion neurons and each one of these can connect up and communicate with thousands of other neurons which means (according to best estimates) the brain may contain between 100 trillion and 1,000 trillion (100,000,000,000 – 1,000,000,000,000) synapses (a synapse is an electrical or chemical connection between neurons).

But to get back to the heart. According to Armour, the heart (with its, admittedly, rather meager number of neurons in comparison to the brain) effectively has its own nervous system that functions independently from the brain (sometimes referred to as the ‘intrinsic cardiac system‘ or, more informally, the ‘heart-brain‘).

Furthermore, according to Armour’s research, the signals that the heart sends up to the brain (i.e. via the ascending, or afferent, pathways) have an effect on the brain’s cognitive processes (i.e. processes related to thinking) and emotional processes (i.e. how we feel).

THE AFFERENT PATHWAY VIA WHICH THESE SIGNALS FROM THE HEART TRAVEL :

The pathway is as follows :

  • START: HEART

  • THEN TO: The brain’s THALAMUS (via VAGAL NERVE)

  • NEXT TO: The brain’s FRONTAL CORTEX

  • AND FINALLY ON TO: The brain’s AMYGDALA

 

HEART COHERENCE :

It has been theorized from within the discipline of cardioneurology that, due to the pathway described above, the level of ‘coherence’ of the heart‘ affects how we think, feel and view the world (particularly in relation to safe and secure we feel within it). ‘Coherence’ refers to the degree to which the heart is harmoniously synchronized with other systems in the body and is a measure of the pattern of the heart’s rhythm.

It has further been theorized (e.g. McCraty et al. 2009) that emotions and feelings can originate from the heart (REMEMBER – THE HEART HAS UP TO 40,000 OF ITS OWN NEURONS CONSTITUTING AN INDEPENDENT NERVOUS SYSTEM) and improve the brain’s activity which in turn can create in the body a sense of equilibrium, order, synchronization, and coherence, thus improving our sense of well-being.

HEART COHERENCE TRAINING :

Many studies have provided evidence that ‘coherence training’ consisting of intentional activation of positive and calming feelings, coupled with HRV (heart rate variability) coherence feedback, can improve the sense of well-being in a variety of populations including those suffering from psychological distress, in part, it is theorized, by helping us learn to generate a calming effect upon the brain’s amygdala (the brain’s amygdala is intimately involved with the body’s fight/flight’ response).

REFERENCES:

J. ANDREW ARMOUR M.D., Ph.D.Intrinsic Cardiac Neurons. Journal of cardiovascular electrophysiology August 1991

Rollin McCraty, Ph.D. et al., 2009. The Coherent Heart Heart–Brain Interactions, Psychophysiological Coherence, and the Emergence of System-Wide Order

Sartor F, Vernillo G, de Morree HM, Bonomi AG, La Torre A, Kubis HP, Veicsteinas A. Estimation of maximal oxygen uptake via submaximal exercise testing in sports, clinical, and home settings. Sports Med. 2013 Sep;43(9):865-73. doi: 10.1007/s40279-013-0068-3. PMID: 23821468.

van der Wall EE, van Gilst WH. Neurocardiology: close interaction between heart and brain. Neth Heart J. 2013;21(2):51-52. doi:10.1007/s12471-012-0369-4

David Hosier BSc Hons; MSc; PGDE(FAHE).