You have mentioned the importance of Bandhas in Pranayama in relation to pressure changes, especially blood pressure. Can you comment further? Also can you comment on the 1:4:2 ratios.
Thank you. A.
The Uddiyana (stomach) and Jalandhara (neck) bandhas in particular activate neurological reflexes called barroreceptor also called pressure regulator reflex. In both the stomach (aorta) and sides of the neck (carotid) are arteries that branch into two trunks. At the junction of both sites these pressure regulators monitor blood pressure and tensions applied to the site. When they message pressure they send a message to the hypothalamus to trigger lowering of heart rate and blood pressure. Through their manipulation, yogis like Krishnamacharya and Swami Rama have been able to alter and stop heartbeats. Proper use of them is beneficial for making positive internal pressure changes.
1:4:2 is the ratio aim of many hatha yogis during pranayama. Inhale for 1, pause (kumbhaka) for 4 and exhale for 2. In general lengthening exhalation tends to move one into meditation, which is beneficial. However I do not support this particular practice, as it tends to lead to too much self-control. Better for me is the encourage to surrender to a higher power than one?s ability to manipulate their breath. Pranayama is for the purpose of uncovering the veil that hides the true nature of the Self (see Patanjali Yoga Sutras II, 52. I find many of the medieval yoga texts like the Hathapradipika have lost the humility training Patanjali sought to preserve in yoga tradition.