Vagal Tone: A Measurable Indicator of Nervous System Health

What is vagal tone?

Vagal tone is the ability of the ventral vagus nerve to regulate the heart beat. It is referred to in medical literature as “cardiac vagal tone.”

The bigger the difference between inhalation heart-rate and exhalation heart-rate, the higher our vagal tone is.

Higher vagal tone means that the body can return to a calm state quickly after a stressful experience ends. Higher vagal tone does not mean a person will be less activated by stressful events, but that they will recover more easily after safety is restored.

So if the vagus is nerve is functioning correctly, why do some people have low vagal tone?

Because a fatty protective layer of insulation around the nerve (called myelination) is weak or almost non-existent. Without insulation, the electrical information in our nerves can’t always travel to its intended destination. Without insulation, the neural information from the vagus gets scattered around the body instead of going straight to the heart.

Low vagal tone is due to low myelination.

Low myelination resulting in low vagal tone is the most common physiological effect of developmental trauma or emotional neglect. Low vagal tone is associated with cardiovascular conditions, strokes, depression, diabetes, chronic fatigue syndrome, and inflammatory conditions.

Generally, industrialized nations do not allow sufficient parent-child bonding time for the development of healthy vagal tone. Low vagal tone is a “silent epidemic” that affects the majority of the population in industrialized countries.

My personal experience with changing vagal tone

6 years ago, when I was diagnosed with complex PTSD, I had low vagal tone. It would take me days to recover from a stressful event. I would often have multiple panic attacks in the same day because I couldn’t calm down after the first one. I could not be left alone for any significant period of time, especially if it was unplanned.

Janae Elisabeth is a researcher-storyteller and neurodiversity advocate from western North Carolina. #actuallyautistic #traumaismyspecialinterest