Understanding Vagal Tone
Vagal tone is a clinical measurement that is calculated by tracking breathing rate alongside heart rate. The greater the difference between inhalation heart rate and exhalation heart rate the higher the vagal tone.
When vagal tone is high, this means the body can regulate quickly after experiencing a stressful incident. This means that blood glucose levels are more regulated which reduces the likelihood of stroke, cardiovascular disease and diabetes.
Low vagal tone has been connected to increased, chronic inflammation and serious disease.
Developed by Dr Stephen Porges, polyvagal theory explains the vital importance of the vagus nerve in our understanding of trauma, and how to effectively treat it.
Prior to his discovery we used to think that the nervous system had two main responses – activation and relaxation.
Porges discovered that we actually have three well defined neural circuits that follow our evolutionary history. These circuits support:
- Social engagement ‘feeling safe and happy to connect’ (ventral vagal responses)
- Mobilisation (fight/flight/excitement – taking action)
- Immobilisation (dorsal vagal freeze & disconnection)
Mammals use the new ventral circuits contained in the face/heart connection convey to others we are safe to approach. This separates our circuits from those of reptiles.
When we are challenged (frightened/upset) we mobilise or shut down and it turns off this ventral vagal connection.