Archive for May, 2019

Respiratory Sinus Arrhythmia is something that happens when you are relaxed and breathing deeply. At around 5-6 breaths per minute your heart beats will synchronize with the inhalation & exhalation of your breath.

As you inhale the heart rate increases & as you exhale it decreases. The breathing rate of 5-6 per minute is where the difference between peak inhalation & exhalation heart rate is highest – a sweet spot.

This is also the training range for Heart Rate Variability & the terms Respiratory Sinus Arrhythmia and Heart Rate Variability  are some times used interchangeably but they are not the exact same thing.

HRV is the difference in timing between heart beats – RSA is the change in the number of beats on inhalation & exhalation – hence they kind of represent the same thing in terms of the ratio of beats per breath – per minute. So a change in RSA is a change in HRV and vice versa. 

HRV measured at the peak of the heart beat also represents RSA and parasympathetic vagal tone.

Respiratory Sinus Arrhythmia is desirable and trainable as the difference between high & low is much greater in people with great cardio vascular fitness. Hence RSA & HRV training can greatly improve your cardiovascular health and fitness. It also stimulate the vagus nerve and autonomic nervous system.

Respiratory Sinus Arrhythmia is not a disease or symptom of disease rather it is a natural physiological phenomena linked to good cardiovascular & autonomic health.

Vagal tone refers to activity of the vagus nerve, the 10th cranial nerve and a fundamental component of the parasympathetic branch of the autonomic nervous system.

Respiratory Sinus Arrhythmia can give an indication of the level of vagal tone.  Hence it can help you enter a more calm autonomic state. This is the fundamental basis of heart rate variability training.  RSA is frequently used as a noninvasive method for investigating vagal tone, in physiological, behavioral, and several clinical studies.

Vagal tone research has the potential to offer insight into social behavior, social interactions, and human psychology. Much of this work has been focused on newborns and children. Baseline vagal tone can be used either as a potential predictor of behavior or as a signal of mental health (particularly emotion regulation, anxiety, and internalizing and externalizing disorders).

The polyvagal theory by Porges is an influential model of how the vagal pathways respond to novelty and to stressful external stimuli. The theory proposes that there are two vagal systems, one that is shared withreptiles and amphibia and a second, more recent, system that is unique to mammals. The two pathways behave differently and can work against each other. This theory can account for several psychophysiologicalphenomena and psychosomatic Illnesses.

RSA and vagal tone are used as markers to help determine the severity of neurodevelopmental disorders such as Autism Spectrum Disorders.^[Children with more secure attachments with their mothers exhibited greater empathetic responsiveness, less social inhibition, and higher vagal tone.