The heart is a unique organ composed of muscle intricately wired by the nervous system. New research suggests the practice of yoga can improve cardiac health by improving control of the nervous system.
For millennia, yoga practitioners have enjoyed benefits of the technique which features breathing exercises, stretching, postures, relaxation, and meditation.
Heart rate variability, a sign of a healthy heart, has been shown to be higher in yoga practitioners than in non-practitioners, according to research to be published in a forthcoming issue of the International Journal of Medical Engineering and Informatics.
The autonomic nervous system regulates the heart rate through two routes — the sympathetic and parasympathetic nervous systems. The autonomic system causes the heart rate to rise, while the parasympathetic slows it.
When working well together, the two ensure that the heart rate is steady but ready to respond to changes caused by eating, the fight or flight response, or arousal.
The ongoing variation of heart rate is known as heart rate variability (HRV), which refers to the beat-to-beat changes in heart rate. In healthy individuals HRV is high whereas cardiac abnormalities lead to a low HRV.
Now, Ramesh Kumar Sunkaria, Vinod Kumar, and Suresh Chandra Saxena of the Electrical Engineering Department, at the Indian Institute of Technology in Roorkee, in Uttrakhand, India, have evaluated two small groups of men in order to see whether yoga practitioners can improve heart health.
The team analyzed the HRV “spectra” of the electrocardiograms (ECG) of 42 healthy male volunteers who are non-yogic practitioners, and 42 who are experienced practitioners. All volunteers were between 18 and 48 years old.
The spectral analysis of HRV is, the team says, an important tool in exploring heart health and the mechanisms of heart rate regulation. The power represented by various spectral bands in short-term HRV are indicative of how well the heart responds to bodily changes controlled by the sympathetic and parasympathetic nervous systems.
The team explains that very low frequency (VLF) variations in the spectra are linked to the body’s internal temperature control. Low frequency peaks are associated with the sympathetic control and high frequency with parasympathetic control.
The team concludes that in their preliminary study of 84 volunteers, there is strengthening of parasympathetic (vagal) control in subjects who regularly practice yoga, which is indicative of better autonomic control over heart rate and a healthier heart.