Chanting energises the vagus nerve for healthy autonomic functions. It promotes mental clarity, creativity and sharp cognitive functions.
Breath is life. Meditating upon its presence is meditating upon our lives. It is the now, the present as it is. We can apply the skill in almost all the things we do daily. As soon as we bring our attention to the breath, the great power of observation comes to us naturally.
Meditation is an advanced and delicate practice. When the mental fluctuations cease abruptly, the subconscious could emerge. The sudden shift could result in the withdrawal the physical energy. This shall trigger the nervous system to increase heat, causing high electrical loads in the nerves and skin. The heart and the lungs could stop due to this. The effects on consciousness can be detrimental if one is not careful.
The bhastrika pranayama directly affects the nervous and circulatory systems. The intracranial pressure abruptly increases through each inhalation which, in turn, magnetises the cerebrospinal fluid.
The subtle body is inherently closed for a significant reason. Once it is made open, the subconscious awakens which in turn emerges our karmas. Hatha Yoga is the most powerful in awakening the kundalini. It is also the most dangerous.
Once the nada is heard, slowly pierce through it until a softer sound appears. Focus on this new sound. Then go past the new sound and another one shall emerge. The nada is inside the mind only and the sound is to be heard in the mind only. We cannot create these sounds, they are already there. We have to attune our minds for the nada to manifest.