Medical science has just discovered the nasal cycle, known to yogis for thousands of years. The first mention in the western hemisphere of a lateralized periodic process was in the work by Dr. R.German rhinologist, in 1895. Dr Kayser found what resembled a periodic rhythm of nostril passage. Dr Kayser suggested that laterality of nostril dominance was part of a larger schema where one lateral side of the body was somehow innervated or de-innervated. Prior to 1895, the Aryan descendants in the Indus valley studied the nasal cycle (Hatha Yoga Pradipika, trans. 1893; Iyengar, 1988). They not only took note of the process, but also had enlarged upon Dr Kayser's theory of lateral innervation.

The doctrine of collateral activation was taken a bit farther by the ancient sages, to include arousal of the brain hemispheres. Yogic sages thought that forced lateralized breathing through one nostril, would effect a selective activation of one brain hemisphere over another. It would appear that nostril dominance originates from the brain itself.


http://www.ncbi.nlm.nih.gov/pubmed/8063547?dopt=AbstractPlus

http://www.ncbi.nlm.nih.gov/pubmed/3449485?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=2&log$=relatedarticles&logdbfrom=pubmed

The nasal cycle is an ultradian rhythm involving alternating breathing of the left and right nostrils,. It is known to have a cycle of two to eight hours (Keuning, 1968; Shannahoff-Khalsa, 1991). The nasal cycle is controlled by sympathetic/parasympathetic innervation of the nasal mucosa. When sympathetic activity to one side dominates, the result is vaso-constriction and thus decongestion on that side, while the enhanced parasympathetic activity on the other side simultaneously results in congestion (Keuning, 1968; Stocksted, 1953). Hence while the nasal cycle is regulated by the autonomic nervous system, it in turn influences the autonomic nervous system mechanism

Researchers at Nepal Medical College in Kathmandu measured the physiological effects of alternate nostril breathing (Nadi Sodhana ). They found significant increases in peak expiratory flow rate (exhale) and pulse pressure and decreases in heart rate, respiratory rate, and diastolic blood pressure.

There is no doubt that alternate nostril breathing can be a powerful way to quickly relax the nervous system, shifting the balance from sympathetic side to the more restorative parasympathetic. By slowing the breath, lengthening the exhalation, and pausing briefly after the exhalation, all tend to shift the balance towards the parasympathetic side.

In other words regular practice of alternate nostril breathing increases parasympathetic activity.
Yoga Journal's medical Editor, Dr Timothy McCall talks about this in Part two of a three part series on "Yoga for chronic Pain"
http://www.yogajournal.com/for_teachers/2561

This is something I have been doing since first being diagnosed with RSD back in 2003. At first when I was diagnosed with full body RSD I wasn't all that thrilled about this exercise, but knew it was absolutely the best thing I could do to stimulate the parasympathetic nervous system into communicating with my brain. See, what happens is one nostril works on the sympathetic nervous system and the other the parasympathetic nervous system. There is a cycle of about 3 hours or so where they switch sides so that the side that was sympathetic became parasympathetic and so on. This style of breathing is very helpful for those of us who have a disturbance of the sympathetic nervous. WHY? Because this style of breathing helps to bring about balance. In so doing, it's calming and calming reduces stress which lessens the perception of pain.

So I persevered and I continue to use this method today. I also recommend it to my Coaching Clients so they can get the benefits of how it calms and reduces pain as early as possible, but it's never too late!

If you are in need of my Coaching services or just curious about me, click link to discover why I am a Coach: "A Winning Life With RSD"