The Nasal Cycle and Brain-Body Function (part 1)

Subtly, rarely noticed, throughout every day of your life and since your first breath this life cycle helps regulate your mood, mental focus and even ability to produce memories, helps coordinate the functions of your glands and organs, hormones, digestion, absorption, detoxification, and cell energy. This cycle controls your sleep and your wakefulness and how your body repairs and regenerates itself; it plays a role in determining how you respond to the world around you – with fear and anger or with calm focus.

First described in western literature in the late 19th century, the nasal cycle was first described and discussed in ancient yoga literature as early as 400BC.

How the nasal cycle works

The nasal cycle is an alternating shift in the volume of air rushing through a nostril, turbinates and sinuses. As the volume of air increases through one nostril, air volume decreases through the other. This continuous nasal cycle takes somewhere around 2 and a half hours and research indicates the effects of this cycle regulate brain functions and, ultimately, function of every cell in your body.

How this nasal cycle occurs opens us to a world of seeming magic and mysteries about how we are made and how we work.

Most of the mucus membranes and tissues within the nasal cavity cover the turbinate bones and divide incoming air into groove-like passages that dramatically increase the surface area contact between incoming air and mucus membranes. Air rushing across the turbinates triggers reflexes in the breathing center of the brain to regulate lung tissues, ribcage muscles, diaphragm and, ultimately, breathing. The turbinates are also responsible for filtering, immune protection from viruses, bacteria and mold, maintaining optimal sense of smell and warming and humidifying incoming air.

Sympathetic nerves of the autonomic nervous system from the cervical/neck area connect to these tissues, including mucus membranes, within the nasal cavity and regulate thickness of the tissues surrounding the turbinates, thereby controlling airflow through the nasal cavity.

How the sympathetic nerves send signals to the nasal cavity – mostly to one side and then the other side in a cycle – is controlled by the hypothalamus, a part of the limbic system in the brain.

As these nerves stimulate more strongly the tissues of the nasal cavity on one side the blood vessels dilate, the tissues swell, the turbinates “close down” and the volume of air moving through the nasal cavity on that side decreases.

In the nasal cavity on the opposite side everything that’s happening is the opposite with the turbinates “opening up” and air flow and volume increasing.

Your brain and the nasal cycle

Now, it starts to get really interesting. When the right turbinates are more “open” there is more airflow through them and more stimulation of the left side of the brain. At that same moment, there is less airflow through the more “closed “ left turbinates and less stimulation of the right side of your brain.

So, due to the nasal cycle there is a cyclical alternating pattern of increased and decreased activity in the the left and right sides of your brain.

Why? Research indicates that this alternating brain activity pattern is essential for keeping your brain and, thereby, the rest of your body in good working order.

And, we will delve into that mystery next time…in part two.