The vagus nerve is the most essential part of the parasympathetic nervous system, the part of our nervous system that is responsible for instilling a sense of calm. It also activates our digestive organs to digest our food and allows for the body to rest.
Vagus is latin for wandering, as this cranial nerve travels from the brain stem, branches out into many nerve fibres and innervates the entire upper abdomen, including the throat and vocal cords, the digestive organs, the heart, lungs, and liver.
When our vagus nerve is toned, it allows for us to switch off our stress response much more quickly and be more adaptive and resilient when faced with stress. People with higher vagal tone may also have increased control of their emotions and enhanced cognition.
Opposing the parasympathetic nervous system is the sympathetic nervous system, the part of our nervous system that activates our stress response. It is responsible for diverting energy away from ‘unnecessary’ physical processes- such as digestion- in times of stress so that we are prepared to fight or take flight.
Unfortunately, in today’s fast-paced high-pressure world, the sympathetic nervous system is persistently activated in response to things perceived as life-threatening (but are actually not- like running late for work or feeling pressured to make a deadline).
As these two parts of the nervous system can’t operate at the same time, when we are stressed, we don’t get a chance to digest our food completely and our bodies can’t rest or be restored.
The result is underutilisation of the vagus nerve and a gradual lack of ‘tone’ meaning that it becomes harder and harder to activate the calming parasympathetic nervous system, to control our stress levels and to absorb nutrients from our food.
Diaphragmatic breathing is slow abdominal breathing.
Because the vagus nerve is connected to our lungs, consciously expanding our lungs and breathing deeply into our belly stimulates nerve cells connected to the vagus nerve which activates the parasympathetic nervous system.
When we reduce our breathing from 9-24 breaths per minute (the usual rate for most people most of the time), to 6 breaths per minute, it leads to changes in our heartbeat that maximises oxygenation of our blood in the lungs, activates our parasympathetic nervous system and increases vagal tone.
Here are a few ways to incorporate diaphragmatic breathing into your day-to-day life:
1. Breathe deeply before eating
Take three deep breaths, as deep as you can go, inhaling fully and exhaling fully, before each meal to activate the vagus nerve. When you have time to breath, your body knows it can relax and focus on digesting your food. Deep breaths reduce stress, allowing the vagus nerve to be activated and innervate our digestive organs so that they can secrete the enzymes and digestive juices needed to breakdown our food.
Ensure you are chewing your food as well as you can, it helps to put your cutlery or food down in between bites and pay attention to your chewing to help slow this down. Avoid rushing and stressing about that long list of things you’ve got to do. Take this time to put yourself first by fuelling yourself with nourishing food. If possible, find a nice calm relaxing environment to eat your food in.
The goal is to stay as stress-free as possible while eating your food.
2. A 2-to-1 breathing technique
Practice a 2-to-1 breathing technique, making your exhalations twice as long as your inhalations. This breathing technique will help to tone your vagus nerve, nourish your nervous system and switch off your stress.
Breathe in quickly and deeply into your belly for 4 counts. Slowly exhale, and actively push the air out for a count of 8 while engaging your abdominal muscles. You can change this to 3 counts and 6 counts- or whatever ratio feels comfortable and can happen smoothly for you.
Try to do this for a few minutes per day. A great time to do this is while on public transport or driving to work to create a level head and quell any anticipatory anxiety about the busy day ahead, and even when travelling back home to switch off for the day and allow yourself to relax. Other times could be before your meditation practice or in the shower.
3. Monitor your breath throughout the day
This is a simple one. Make it your goal to be more conscious of your breath throughout the day and take a deep breath and extend the exhalation every time you feel it becomes shallow. Shallow breathing will be triggered by and contribute to an excessive stress response so catching yourself when you start to do this and consciously changing your breath will help prevent your stress from spiralling out of control.
 Gerritsen, Roderik J. S. and Guido P. H. Band. 2018. “Breath of Life: The Respiratory Vagal Stimulation Model of Contemplative Activity.” Frontiers in Human Neuroscience 12.
 Lehrer, Paul M. and Richard Gevirtz. 2014. “Heart Rate Variability Biofeedback: How and Why Does It Work?” Frontiers in Psychology 5.