To understand how the vagus nerve works, you broadly need to know how the autonomic nervous system functions.
The autonomic nervous system is divided into two parts that are both involved in our stress regulation: the sympathetic and the parasympathetic nervous systems. The sympathetic nervous system is activated when the body needs more power, while the parasympathetic is most active when we are resting.
When we are faced with dangerous situations, the sympathetic nervous system kicks in. Various substances and stress hormones are released and sent into the bloodstream. The body is now prepared for battle, whether the threat is a life‑threatening situation or we are worried about having missed an important meeting. The parasympathetic system, in turn, builds up our body and counteracts the effects of the sympathetic nervous system. It is needed when we need to wind down and recover.
What is the vagus nerve and what does it do? The vagus nerve is the body’s largest nerve and a signaling pathway between the brain and the internal organs. The vagus nerve activates the parasympathetic nervous system and basically works like a button you can press to reduce stress. It originates in the brain and travels down to the internal organs through the neck, chest, diaphragm, heart and lungs. Like a muscle, you can train the vagus nerve so that it becomes stronger. Increasing your vagal tone (the activity of the vagus nerve) is one of the most useful ways to quickly improve your overall well‑being. As a general rule, the higher your vagal tone, the better the body can regulate the internal systems that keep you healthy, such as the cardiovascular system, blood sugar levels and the immune system. You can stimulate the vagus nerve yourself, and thereby influence your parasympathetic activation, with breathing exercises, massage, intermittent fasting, taking omega‑3 supplements, cold/heat thermogenesis, physical exercise and more. Activities such as laughter, sex and singing also stimulate the vagus nerve and thus activate the parasympathetic nervous system.
Breathing with the diaphragm (conscious deep breathing) Consciously regulating internal bodily states (for example, actively lowering heart rate during the day with conscious breathing) increases emotional control and psychological well‑being. The principle for calming the system is to limit the number of sensory inputs (i.e. sounds, light and potentially certain smells) and use conscious breathing or body scanning (noticing body parts and bodily sensations in a gradual sequence from feet to head) as a mechanism to focus attention away from the mind. As little as 1 minute of conscious deep breathing a few times a day has been shown to have a beneficial effect on the heart‑lung system and improve parasympathetic activation.
