The Automatic Nervous System (ANS) controls internal body processes such as digestion, blood pressure, heart rate, breathing, body temperature, and so on- all these systems work automatically without conscious effort.
This ANS has two main divisions:
The Sympathetic and Parasympathetic Nervous Systems.
The Sympathetic nervous system is about stimulation and the Parasympathetic nervous system about inhibition. Any time the brain perceives a threat or feels stress, the SNS is switched on triggering the famous, “Fight or Flight” response. The PNS, on the other hand, plays the role of the opposition party, countering the effect leading to the phenomenon of “Rest and Digest” or the “Cool and Chill”, in which blood pressure decrease, breathing, and heart rate slows down. The PNS is activated when you are out of danger or feeling no longer distressed. However, sometimes, the brain remains in distress or panic mode wherein lies the danger of becoming chronic.
Here enters the hero- The Vagus nerve, which acts as a remote control of PNS helps you to calm and tone down. It thus plays a big part in relaxation response- for example, immediately after a stressful situation. By the way, only mammals have this nerve- a gift from mother nature. Say Thank you!
The vagus nerve gets its name from the Latin word for wandering. The words like vagabond and vague are close relatives as they too are derived from the same latin family. True to its name the vagus nerve wanders throughout the body originating from the brain up to the lowest part of the abdomen connecting the heart and touching other major internal organs like lungs, kidneys, liver, pancreas, and spleen along the way. It is the largest and most widely spread cranial nerve branching like a system of roots and cables.
This nerve serves as the body’s super expressway, carrying information and sensory signals between the brain and other internal organs of the body. It picks up information from different parts of the body and sends it back to the brain for further analysis and interpretation. The brain then sends commands back to the organs modulating very essential processes. It plays a major part in how the brain and body function. So, if it is stimulated, we can receive an immediate release from stress.
A German physiologist Otto Loewi in 1921 discovered that when the vagus nerve was stimulated, it triggered the release of a substance which resulted in the reduction of heart rate. He named the substance Vagusstoff- a German word for vagus substance. This substance is now known as acetylcholine a very important neurotransmitter in our nervous system.
One of the most powerful ways to stimulate the vagus nerve is deep and slow breathing. Christopher Bergland, author of the book, “Athlete’s Way; Sweat and the Biology of Bliss” writes that deep breathing with long exhales results in the release of acetylcholine which acts as a natural tranquilizer.
When your exhale is even a few counts longer than your inhale, the vagus nerve sends a signal to your brain to turn up your parasympathetic nervous system. When you’re exhaling heart rate is the lowest and vagal activity highest.
The Heart and neck contain neurons that have receptors called “Baroreceptors” also called as stretch receptors. These receptors are quite sensitive to rapid changes in blood pressure. They specialize in registering both increase and drop in blood pressure and then transmit the information to the brain generating action.
If a person’s blood pressure is high, an impulse is generated which is carried to the heart via the parasympathetic vagus nerve. The end result is a decrease in blood pressure and heart rate. This phenomenon is known as the buffering effect meaning the change in blood pressure is buffered back to normal.
Baroreceptors can be variably sensitive. Some scientists believe that the more sensitive these Baroreceptors are, the more likely they are going to trigger and tell the brain that the blood pressure is too high and it’s time to activate the vagus nerve to lower it. This is called Baroreceptor sensitivity (BRS).
Researchers from UK and Italy carried out a study with 17 participants in which they were subjected to 4 breathing protocols.
Controlled breathing at 15 breaths per minute.
Controlled breathing at 6 breaths per minute with 5 seconds inhale and exhale.
Controlled breathing at 6 breaths per minute with 3 seconds inhale and 7 seconds exhale.
Both 6 breaths per minute protocols, but with ujjayi pranayama.
The results showed that all of the slow breathing techniques improved BRS and lowered blood pressure. Deep breathing triggers and turns on the vagus nerve which applies brake on the stress response.
The vagus nerve is listening to the way you breathe. So slow breathing reduces the oxygen demands of the heart leading to a drop in the heart rate and the blood pressure. Put another way when you breathe slowly the heart slows and relaxation happens.
Another slow abdominal breathing called Diaphragmatic breathing is also observed to stimulate the vagus nerve and hijacks the “flight-or-fight” stress mechanism. One powerful way to measure your vagal tone is to measure heart rate variability (HRV). HRV is a measurement of heart rate variations between two breaths, a breath in and a breath out.
In a research paper published in the journal Frontiers in 2014, researchers Paul M. Lehrer and Richard Gevirtz explored the role of HRV biofeedback in improving the vagal tone. They found out that people with higher HRV (which means healthy vagal tone) displayed lower biomarkers for stress, better cognitive functions, and increased psychological and physical resilience.
It is no surprise that slow and deep breathing has been the cornerstone and foundation of yoga and meditation. For ages, Our Yogis have well understood the importance of breathing.
Now, do you need any more reason to breathe deep and slow? Next time when you’re in any stressful situation anytime and anywhere and just don’t know how to respond- the best way is to slow down you’re breathing just for one to two minutes. Immediately you will put yourself in a calmer state which will allow you to think and feel better. Since, words are nothing but verbal thoughts, you’ll be able to communicate better and if you can think and communicate better you will decide and act right.
Let me know your thoughts and experience on the importance of deep breathing in the comments section below!
Happy Deep Breathing!