11/03/2021
Heart Rate Variability Reflects Your Nervous System
HRV is linked to your autonomic nervous system (ANS) and the balance between the parasympathetic (rest-and-digest) and sympathetic (fight-or-flight) branches. By balancing the two forces, the ANS helps you respond to daily stressors and regulate some of your body’s most important systems, including heart rate, respiration, and digestion.
HRV is the most effective way of estimating your ANS balance, as it directly impacts your heart’s activity.
Independently, your heart beats to its own rhythm thanks to a built-in pacemaker called the sinoatrial (SA) node. Your SA keeps your heart firing at around 100 beats per minute.
However, your ANS greatly influences how your heart beats. All the cells within your heart’s pacemaker have direct phone lines from both sides of your ANS. They give input, beat to beat, on a cellular level to your heart:
*Your rest-and-digest tells your heart to slow down, making room for variability between beats (higher HRV)
*Your fight-or-flight system tells your heart to speed up, limiting space for variability (lower HRV)
These two systems can be silent, active, or shouting over each other at any given time. That’s a lot of conversation, and it leads to a lot of variation.