A growing wealth of studies in the field of Contemplative Neuroscience are reporting a variety of positive mental and physical effects from meditation, yoga, and breathing. It is widely reported in these studies that slow, controlled breathing—<10 breaths per minute—affects the brain-body physiology, but the mechanisms behind this are still being sought. Breathing is intimately linked with mental functions. In the eastern tradition, the act of breathing is an essential aspect of most meditative practices and is a critical pathway for reaching an altered state of consciousness. In the Indian tradition, Pranayama breathing techniques are integral to yoga training, but is also part of other styles of meditation (Jerath et al., 2006).
A model proposed by Gard et al. (2013) hypothesizes that yoga may involve a system of brain areas which engage in top-down processing including attention, working memory, and executive monitoring. Brain networks associated with these functions make up the central executive network. This network is composed of the dorsolateral prefrontal and the posterior parietal cortices, the frontal-parietal lobe network including the dorsolateral prefrontal and the anterior cingulate cortices, the inferior frontal junction, the pre-supplementary motor area, and the intraparietal sulcus (Goulden et al., 2014; Harding et al., 2015; Seeley et al., 2007; Vincent et al., 2008).
Taylor et al. (2010) in a review about mind-body therapies (i.e., techniques focusing on functional links between mind and body) such as slow breathing techniques, suggested the existence of an executive homeostatic network as a fundamental substrate of these practices. This network includes the anterior cingulate, the prefrontal and the insular cortices, areas involved in physiological self-awareness and cognitive modulation.
A recent systematic review of the research aimed at finding these psychophysiological mechanisms and their effects on healthy subjects. A wide search of past studies focusing on cardiovascular and central nervous system was conducted. It found that slow breathing stimulates increases heart rate and respiratory sinus activity. EEG studies found that slow breathing increases the brain’s alpha wave output—the frequency associated with relaxation while decreasing beta waves which are related to active consciousness. One fMRI study showed that slowed breathing increased activity in the prefrontal, motor, and parietal areas and in subcortical such as the pons, thalamus, sub-parabrachial nucleus, periaqueductal gray, and hypothalamus. Psychological reports conducted along with these studies indicate that test subjects experienced more comfort, relaxation, vigor and alertness during and after controlled breathing (Zaccaro et al., 2018).
In general, slow breathing techniques enhance interactions between autonomic, cerebral and psychological flexibility. It helps to link the parasympathetic nervous system (PNS) and central nervous system (CNS) activities related to emotional stability and personal well-being. Slow breathing techniques apparently increase PNS activity while being mediated by the vagus nerve. The vagus nerve, in turn, relays bodily information from digestive, heart, and respiratory areas to the CNS via the Nucleus of the Tractus Solitarius. This neural tract sends its own projection to the thalamus and limbic system via the parabrachial nucleus (Zaccaro et al., 2018).
Closing Thoughts
This is great article confirming after an extensive database search of breathing studies that slow breathing has positive effects on the cardiovascular and nervous systems. The weakness of the article is that most of the studies from a pool of 2,461 most were of poor quality and excluded from the study. The findings were based on 15 solid studies. That’s not a lot, but it’s a pretty good start. More research, as they always say, is needed.
Paul Shane, Ph.D., LMT
Director, Academic Content
References
Gard, T., Noggle, J., Park, C., Vago, D., and Wilson, A. (2014). Potential self-regulatory mechanisms of yoga for psychological health. Frontiers in Human Neuroscience 8, Article 770, doi: 10.3389/fnhum.2014.00770.
Goulden, N., Khusnulina, A., Davis, N., Bracewell, R., Bokde, A., McNulty, J., & Mullins, P. (2014). The salience network is responsible for switching between the default mode network and the central executive network: replication from DCM. Neuroimage 99, p. 180–190.
Jerath, R., Edry, J., Barnes, V., and Jerath, V. (2006). Physiology of long pranayamic breathing: Neural respiratory elements may provide a mechanism that explains how slow deep breathing shifts the autonomic nervous system. Medical Hypotheses 67, p. 566–571.
Taylor, A., Goehler, L., Galper, D., Innes, K., and Bourguignon, C. (2010). Top-down and bottom-up mechanisms in mind-body medicine: Development of an integrative framework for psychophysiological research. Explore 6, p. 29–41.
Zaccaro, A., Piarulli, A., Laurino, M., Garbella, E., Menicucci, D., Neri, B., & Gemignani, A. (2018). How breath-control can change your life: A systematic review on psycho-physiological correlates of slow breathing. Frontiers n Human Neuroscience 12, Article 353, doi: 10.3389/fnhum.2018.00353.