“Healthy vagal tone is indicated by a slight increase of heart rate when you inhale, and a decrease of heart rate when you exhale. Deep diaphragmatic breathing—with a long, slow exhale—is key to stimulating the vagus nerve and slowing heart rate and blood pressure, especially in times of performance anxiety. A higher vagal tone index is linked to physical and psychological well-being. A low vagal tone index is linked to inflammation, negative moods, loneliness, and heart attacks.
“Heart disease is the number one killer in America. One way to improve your heart health is to focus on the vagus-friendly lifestyle habits I explore below. Well-conditioned athletes have higher vagal tone because aerobic breathing creates healthy vagal tone, which results in a lower resting heart rate. Healthy cardiac function is directly linked to stimulating the vagus nerve.
“In 1921, a German physiologist named Otto Loewi discovered that stimulating the vagus nerve caused a reduction in heart rate by triggering the release of a substance he coined Vagusstoff (German: “Vagus Substance”). The “vagus substance” was later identified as acetylcholine and became the first neurotransmitter identified by scientists.
“Vagusstuff is literally a tranquilizer that you can self-administer simply by taking a few deep breaths with long exhales. You can consciously tap the power of your vagus nerve to create inner-calm on demand. This knowledge alone should be enough to reduce the fear-of-fear-itself and give you grace under pressure next time you need it.”
Read further about the 8 habits for a healthier vagus in Christopher Bergland’s full article at Psychology Today: The Neurobiology of Grace Under Pressure.