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Nasal cycle

Nadi Shodhan Pranayam, (anulom- vilom pranayam) and modern medicine
Dr. Avinash Joshi

Nasal cycle

Nasal cycle is the alternating obstruction of the nostrils in humans. It is a physiological congestion of the nasal concha due to selective activation of one half of the autonomic nervous system (ANS) by the hypothalamus. It should not be confused with pathological congestion .Although yogis knew it since ancient times, it was first described by German rhinologist, Kayser in 1895 Nostrils have erectile tissues similar to those found in male and female sex organs. Increased sympathetic tone on one side leads to septal vasoconstricion and decreased resistance to airflow on that side.
Nasal cycle is found in 80% of normal population. Nasal cycle has  a  duration of 40 minuets to 2.5 hours as measured by rhinomanometry. The dependent nostril is blocked while sleeping in lateral position. Some postulate that this alternating positional obstruction has the purpose of causing a person to turn from one side to the other while sleeping.

Autonomic Nervous System(ANS)

ANS is regulated by hypothalamus. Most organs including the cerebral cortex are innervated by fibers from sympathetic nervous system (SNS) and parasympathetic nervous system (PNS), that have opposing effects.SNS prepares us for fight or flight response while PNS activation leads to rest, conservation and restoration of energy, reduction in heart rate and blood pressour, facilitation of digestive processes and elimination of waste products.


ANS has lateralized ultradian rhythms.SNS  dominates one side of the body while PNS dominates on the opposite side( including cerebral hemispheres), and then the two systems switch dominance on the two sides . Each dominance lasting for 40 minuets to2.5 hours. The secretions of catecholamine on both sides of the body is coupled with nasal cycles .Hence minor differences in blood pressour and blood sugar measurements on both sides may be seen at the same time. studies have shown that this lateralized ultradian rhythm is coupled to the ultradian rhythms of neuroendocrine, cardiovascular and insulin systems. Catecholamine secretion on the two sides varies  periodically .It has been proposed that the nasal cycle is a marker for psychophysiological states. Right nostril dominance marks activity phase of BRAC(Basic Rest Activity Cycle) and left nostril dominance marks the rest phase.

Nasal cycle is unique marker of lateralized rhythms of the ultradian rhythm of cerebral rhythmic activity during awake period as well as during sleep.Ultradian rhythms are the circadian rhythms in body whose duration is less than twenty-four hours. Infradian rhythms have rhythms have duration more than twenty four hours, like menstrual cycles.

potential of UFNB(unilateral forced nasal breathing). The ANS is thought of mostly as an efferent fiber system however the vagus is a mixed nerve and 80% of the fibers are afferent sensory fibers, carrying information to the brain from head, neck, thorax and abdomen.

This afferent fibre system makes Vagal Nerve Stimulation(VNS), a useful therapeutic tool. The influences of the left and right vagus nerve are not identical. Left VNS is therapeutic and right VNS can lead to increased cardiac instability .

VNS was approved by US FDA for the treatment epilepsy and in 2005, for treatment of resistant depression in 2009.

Yogis refer to vagus nerve as ‘mind nerve’. The effect of Vagal Nerve Stimulation on depression, OCD and other anxiety disorders can be achieved by left UFNB which is non invasive.


According to ancient Indian wisdom nadis (tubes or pipes )are the channels through which energies of the subtle body are said to flow. They connect at special points called chakras. Nadis are not nerves. but rather channels for the flow of consciousness, just as the negative or positive forces of electricity flow through the complex circuits. As per this wisdom there are 72000 or more such channels through which the stimuli flow like an electric current  from one point to the other.
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