The Science
Vagal Nerve Stimulation:
https://pmc.ncbi.nlm.nih.gov/articles/PMC7563188/
Heart rate variability:
Polyvagal Theory:
https://www.polyvagalinstitute.org/
https://pubmed.ncbi.nlm.nih.gov/35645742/
https://pubmed.ncbi.nlm.nih.gov/35757052/
https://pubmed.ncbi.nlm.nih.gov/38108034/
https://pubmed.ncbi.nlm.nih.gov/35941799/
Genes - our molecular biology:
https://pmc.ncbi.nlm.nih.gov/articles/PMC6779418/