Heart Rate Variability

What is heart rate variability and why does it matter?

Heart rate variability (HRV) is a measurement of the variation in time between successive heartbeats. You can track the indicator using an at-home sensor to get an important glimpse into how you respond to stress and how your health and well-being are trending.

HRV is not the same as heart rate

When people first discover HRV, they often confuse it with heart rate. However, the two indicators couldn’t be more different. Heart rate measures how many times your heart beats per minute, while HRV measures the changes in time (or variability) between successive heartbeats. The time between beats is measured in milliseconds (ms) and is called an “R-R interval” or “inter-beat interval (IBI).

Both heart rate and HRV are measurements of the heart. However, the power of HRV rests in its insight into the autonomic nervous system (ANS), the body’s main control system for self-regulation.

HRV and the Autonomic Nervous System

Even when the body is completely at rest, a grand balancing act — called homeostasis — is taking place. Homeostasis means “changing to stay the same,” and is central to understanding how even the simplest single-celled organisms stay alive.

The ANS helps us maintain homeostasis through its two branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS).

The sympathetic nervous system (SNS) controls your body’s “fight or flight” reactions in response to internal and external stressors. It stimulates blood glucose (to fuel your muscles) and pupildilation (to see the threat better), slows digestion (to focus energy on the present danger), and increases heart rate (to ensure adequate blood circulation to run or fight). 

The SNS is ideally activated to overcome short-term stress situations such as running from a tiger or fighting an intruder. However, the response also occurs when you exercise, perform challenging mental tasks, get in an argument, or even sit in traffic.

The parasympathetic nervous system (PSNS) controls your “rest and digest” responses and is associated with recovery. Parasympathetic activation conserves energy, constricts pupils, aids digestion, and slows the heart rate. The PSNS is meant to help build for the long term and is needed to grow faster, stronger, and healthier.

What gives rise to heart rate variability?

Think of the body like a race car: The SNS is like the accelerator, revving you up in stressful situations, and the PSNS is like the braking system, returning the body to a resting state after the stressor has passed.With every heartbeat, your nervous system says “slow down” or “speed up” based on feedback from your senses and emotions. As you navigate the world, your ANS sets the relative balance of the SNS and PSNS based on what’s happening at that moment.

Sometimes, this balance leans toward the SNS (like when something stressful is happening). Other times, it leans toward the PSNS (like when you’re sleeping or chilling out).

The Autonomic Nervous System (ANS) is part of the body’s balance-regulating system. The Heart Rate Variability test can guide inform us if the ANS is in a state of dys-regulation. In Blocked Regulation, the ANS has been stressed by one or multiple stressors that must be addressed to allow for healing to occur. These are immune challenges, food sensitivities, scars, heavy metal toxicity (such as to aluminum, mercury or lead), and chemicals, or other kinds of sensitivities (jewelry, clothing, radio frequencies, etc). These same factors may cause confusion within the ANS, also known as neurogenic switching.

Heart Rate Variability (HRV) or Nerve Express monitoring is a simple non-invasive test that also can reveal deeper levels of Blocking or Switching.