This is simple breathing. Swami Vivekanand always exercised this, before going into his meditation.
- Sit in any Asana that you are comfortable. Sit keeping spine and neck straight.
- Close your eyes and keep both hands on your knees. (called as Dnyan Mudra)
- Deep inhale (Poorak) and then deep exhale (Rechak).
- Keep the pace of Poorak and Rechak same. Do at slow pace not fast. You might like counting, upto 10 counts you inhale and another counts you exhale.
- Your chest portion expands while you inhale, and tummy goes inside as you exhale.
- Concentrate on the process on air coming in and going out. Imagine the air is coming in your left or right side hollow tubes around spine (knows as Nadis, which are two, Ida on right side and Pingala on left side)
- Imagine that as you inhale, you are impacting with air on your sleeping Kundalini, and while you exhale out, you are pulling it up along with air or some energy you are pulling in.
Do this process staring from 10 minutes twice everyday. Once you are comfortable with this the process, increase upto, forty five minutes to one hour in two-three weeks if possible.
The benefits are apparent after few days, if followed regularly. You shall experience calmness and peace within. This helps reduce anger and aids in curing diseases.
This internally cleanses body and aids ascension of Kundalini. This aids achieving good concentration needed for meditation (dhyana).