ScienceDaily (Nov. 9, 2009) — 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 former 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. Anecdotal evidence
would suggest that yoga practice may improve health through breathing exercises,
stretching, postures, relaxation, and meditation.
The team analyzed the HRV "spectra" of the electrocardiograms (ECG) of forty two
healthy male volunteers who are non-yogic practitioners, and forty two who are
experienced practitioners, all volunteers were aged between 18 and 48 years.
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 changes in the body controlled by the sympathetic and the
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 so a healthier heart.
Source : ScienceDaily LLC
