Normalize Heart Rate Processes with Yoga Practice
By John M. de Castro, Ph.D.
“Heart Rate Variability is the ability of the heart rate to change from beat to beat., which is based off the activity of the nervous system. HRV is a more accurate measure of a person’s health than examining only the heart rate.” – Zelinda Yañez
In our lives we are confronted with a variety of situations and environments. In order to successfully navigate these differing situations, we must be able to adapt and self-regulate. The Autonomic Nervous System (ANS) is designed to adapt physiologically to the varying demands on us. It is composed of 2 divisions; the sympathetic division underlies activation, including increases in heart rate and blood pressure, while the parasympathetic division underlies relaxation, including decreases in heart rate and blood pressure. A measure of the balance between these systems is provided by the variability of the heart rate.
Heart Rate Variability (HRV) refers to the change in the time intervals between consecutive heart beats. Higher levels of HRV are indicative of flexibility in the Autonomic Nervous System and are associated with adaptability to varying environments. Mindfulness has been associated with psychological flexibility and a greater ability to adapt appropriately to differing situations. Indeed, mindfulness practice improves Heart Rate Variability (HRV). It makes sense to determine if yoga practice can also improve heart rate variability.
In today’s Research News article “Changes in Heart Rate Variability after Yoga are Dependent on Heart Rate Variability at Baseline and during Yoga: A Study Showing Autonomic Normalization Effect in Yoga-Naïve and Experienced Subjects.” (See summary below or view the full text of the study at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336948/) Shinba and colleagues recruited adults who were either experienced yoga practitioners or yoga naïve. The engaged in 20 minutes of seated breath awareness and yogic breathing exercises. Their electrocardiogram heart rates were recorded before, during, and after the practice.
They found that the low frequency component of heart rate variability and the ratio of the low frequency to the high frequency component were normalized after yoga practice such that when the baseline levels were low the components increased as a result of yoga practice and when the baseline levels were high the components decreased. No significant changes in the high frequency component was observed.
The results do not replicate previous findings that yoga practice increases the high frequency component of heart rate variability reflecting an increase in parasympathetic activity which is associated with physiological relaxation. This lack of replication may be due to the brevity of the practice or to the nature of the practice where only breath awareness and breathing exercises were included. It is possible that more active components such as postures are needed to produce increases in parasympathetic activity.
The low frequency component of heart rate variability reflects the regulation of the heart rate based upon blood pressure. This reflects the maintenance of an adequate blood flow at all times. Hence, the present brief breath-oriented yoga practice appears to regularize blood flows. This, in turn, may reflect an increased ability of the physiology to deal with stresses.
So, normalize heart rate processes with yoga practice.
“HRV is an interesting and noninvasive way to identify these ANS imbalances. If a person’s system is in more of a fight-or-flight mode, the variation between subsequent heartbeats is low. If one is in a more relaxed state, the variation between beats is high. In other words, the healthier the ANS the faster you are able to switch gears, showing more resilience and flexibility.” – Marcelo Campos
CMCS – Center for Mindfulness and Contemplative Studies
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Study Summary
Shinba, T., Inoue, T., Matsui, T., Kimura, K. K., Itokawa, M., & Arai, M. (2020). Changes in Heart Rate Variability after Yoga are Dependent on Heart Rate Variability at Baseline and during Yoga: A Study Showing Autonomic Normalization Effect in Yoga-Naïve and Experienced Subjects. International journal of yoga, 13(2), 160–167. https://doi.org/10.4103/ijoy.IJOY_39_19
Abstract
Background:
Yoga therapy is widely applied to the maintenance of health and to treatment of various illnesses. Previous researches indicate the involvement of autonomic control in its effects, although the general agreement has not been reached regarding the acute modulation of autonomic function.
Aim:
The present study aimed at revealing the acute effect of yoga on the autonomic activity using heart rate variability (HRV) measurement.
Methods:
Twenty-seven healthy controls participated in the present study. Fifteen of them (39.5 ± 8.5 years old) were naïve and 12 (45.1 ± 7.0 years old) were experienced in yoga. Yoga skills included breath awareness, two types of asana, and two types of pranayama. HRV was measured at the baseline, during yoga, and at the resting state after yoga.
Results:
In both yoga-naïve and experienced participants, the changes in low-frequency (LF) component of HRV and its ratio to high-frequency (HF) component (LF/HF) after yoga were found to be correlated negatively with the baseline data. The changes in LF after yoga were also correlated with LF during yoga. The changes in HF as well as the raw HRV data after yoga were not related to the baseline HRV or the HRV during yoga.
Conclusion:
The results indicate that yoga leads to an increase in LF when LF is low and leads to a decrease in LF when it is high at the baseline. This normalization of LF is dependent on the autonomic modulation during yoga and may underlie the clinical effectiveness of yoga therapy both in yoga-naïve and experienced subjects.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336948/