Autonomic Nervous System & Heart Rate Variability
WHAT IS ANS?
The Autonomic Nervous System (ANS) is indeed responsible for innervating internal organs, regulating involuntary bodily functions such as heart rate, digestion, respiratory rate, pupillary response, and more. It consists of two main divisions: the sympathetic nervous system, often associated with the "fight or flight" response, and the parasympathetic nervous system, often associated with the "rest and digest" response.
When the autonomic nervous system is not functioning properly, it can manifest in a variety of symptoms, including headaches or migraines, heartburn, dizziness, pain, anxiety, abnormal heart rhythms, or gastrointestinal problems. These symptoms often indicate an imbalance or dysfunction within the ANS, which may require further evaluation and management to restore proper functioning and alleviate symptoms.
WHAT IS HRV?
Heart Rate Variability (HRV) is a quantitative measure of the variation in the time intervals between heartbeats. It reflects the dynamic interplay between the sympathetic and parasympathetic branches of the autonomic nervous system in regulating heart rate, reflecting the capacity of the ANS to adjust and maintain homeostasis.
Decreased HRV, particularly in the time domain, has been associated with autonomic dysfunction and has been observed in various disease states. Moreover, reduced HRV has been correlated with increased mortality and morbidity across different health conditions.
Therefore, monitoring HRV can provide valuable insights into autonomic function and overall health status, as it serves as a marker for autonomic balance and cardiovascular health. It is considered a sensitive, non-invasive measurement of autonomic input to the heart. It provides measures of autonomic nervous system activity in both sympathetic (SNS) and parasympathetic (PNS) branches.
Since systems involved in autonomic control are strictly connected with those involved in pain perception, HRV can be considered a reliable index of ANS reactivity to nociceptive stimulation, which can be used to effectively manage chronic pain. Patients with chronic pain show a reduction in HRV and baroreflex sensibility due to changes in efferent sympathetic and parasympathetic cardiac activity, which shift the balance to a sympathetic tone prevalence related to catecholamine release.
Numerous factors influence HRV, spanning from pathological conditions to environmental and lifestyle factors, as well as genetic predispositions. Physiological variables such as age, gender, and fitness level, along with psychological factors like stress and anxiety, can significantly impact HRV. Additionally, environmental factors such as temperature, altitude, and pollution, as well as lifestyle factors like diet, exercise, and sleep quality, all play a role in shaping HRV.
By measuring the HRV through a Polar band, Esteban can gain a more comprehensive understanding of an individual's health status and overall wellbeing.