Contemplative science is an emerging field of knowledge focusing on how contemplative practices such as meditation, yoga, and tai chi ch’uan affect the mind, brain, and body. One technique studied by contemplative science is controlled breathing. Studies show that slow, controlled breathing—less than 10 breaths per minute—affect the body’s physiology and brain functioning, but how this occurs remains unknown. Conscious breathing in the eastern tradition is an integral part of meditation and the gateway to achieving an altered state of consciousness (Jerath et al., 2006).
Gard et al. (2013) envisions a model in which yoga activates brain areas involved in top-down processing including attention, working memory, and thinking. Brain networks associated with these functions make up the central executive network (CEN). This network is made up by 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). The CEN is also known as the “external mind.” Taylor et al. (2010) suggests the existence of an executive homeostatic network as a fundamental substrate supporting mind-body practices including controlled breathing. 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 examined all past research on these neuropsychological mechanisms and their effects on healthy subjects. Part of the search yielded past studies on cardiovascular and central nervous system activity. It was 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. There were many reports from test subjects that controlled breathing made them feel more comfortable, relaxed, vigorous, and alert (Zaccaro et al., 2018).
In general, slow breathing techniques enhance the performance of the autonomic and cerebral systems. It bridges the parasympathetic nervous system (PNS) and central nervous system (CNS) especially in the connections related to emotional stability and personal well-being. Slow breathing techniques apparently increase PNS activity while being modulated 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
The Zaccaro meta-analytic study is a 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.
But, based on the above information, it is clear that contemplative science is a fertile enterprise that is carrying us closer to understanding the mechanisms by which controlled breathing effects its changes on the bodymind.
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.